Major interaction on record — check this product against your medications before combining. Based on 11 of 19 ingredients. Check your meds →
Dietary supplement

Shredded-AF Ingredients & Drug Interactions

by Steel

Shredded-AF label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Shredded-AF against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Shredded-AF is a dietary supplement by Steel with 19 active ingredients. Its ingredients are commonly taken for morning sickness in pregnancy, premenstrual syndrome (pms), preventing or treating b6 deficiency.Based on those ingredients, 1,596 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Black Pepper Fruit Extract, Alpha Yohimbine, Theobromine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Shredded-AF by Steel

Ask about any prescription or over-the-counter medication and we check it for interactions with Shredded-AF by Steel — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Shredded-AF by Steel

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Sep 10, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 19 of its 19 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

Shredded-AF contains 19 ingredients, of which most are active compounds. The lineup includes vitamin B6 and vitamin B12 (for energy and metabolism), caffeine anhydrous and theobromine (stimulants from caffeine and cocoa), theacrine and isopropylnorsynephrine (stimulant-type compounds), and alpha yohimbine (an extract related to yohimbine).

You'll also find huperzine A (an acetylcholinesterase inhibitor used in some cognitive formulas), phenylethylamine HCl (a stimulant precursor), and black pepper fruit extract (often added to boost absorption of other ingredients). Several other actives—N-acetyl-L-tyrosine, LeanGBB, grains of paradise, and 3,5 diiodo-L-thyronine—round out the formula, along with Dynamine and Senactiv (proprietary compounds).

The inactive ingredients are gelatin, magnesium stearate, and silicon dioxide.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: fat loss, appetite control, and energy.
  • We looked for evidence on: Athletic performance, Attention, Cognitive function, Fatigue, weight management, metabolic support — and 1 related terms.
  • The strongest evidence on file: Caffeine is rated "Likely Effective" for Athletic performance (Natural Medicines).
  • Also on file: Caffeine is rated "Likely Effective" for Mental alertness.
  • Also on file: Caffeine is rated "Possibly Ineffective" for Attention deficit-hyperactivity disorder (ADHD).

The evidence varies widely across these ingredients. Vitamin B6 is effective for sideroblastic anemia and vitamin B6 deficiency, and likely effective for high homocysteine.

Caffeine is effective for neonatal apnea and postoperative headache, and likely effective for mental alertness and athletic performance. Vitamin B12 is effective for B12 deficiency and cyanide poisoning.

Black pepper is generally rated as having insufficient evidence for most uses listed in our data. Theobromine (cocoa) is possibly effective for cardiovascular health but possibly ineffective for stretch marks.

Huperzine A is possibly effective for Alzheimer disease. Theacrine, alpha yohimbine, isopropylnorsynephrine, and phenylethylamine are all rated as having insufficient evidence for their claimed uses—athletic performance, cognitive function, and related outcomes—so we cannot confirm they work for these purposes based on the data we hold.

The evidence, ingredient by ingredient Vitamin B6 Caffeine Cocoa Theacrine Vitamin B12 Rauwolscine Isopropylnorsynephrine Black Pepper

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 9 of the 11 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 10 of 11.
  • General safety write-ups exist for 11 of 11.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin B6 is generally well tolerated at normal doses, but high doses over time can harm nerves (sensory neuropathy). Caffeine is well tolerated in moderate amounts in healthy adults but can cause anxiety, insomnia, jitteriness, and restlessness; high doses may pose cardiovascular risks.

Vitamin B12 is very safe with no established upper limit. Theobromine and cocoa are generally well tolerated in food amounts.

Theacrine short-term use appears generally well tolerated, but long-term safety is not established. Alpha yohimbine is a potent stimulant with limited human data and can affect heart rate and blood pressure.

Isopropylnorsynephrine is poorly studied and regarded as unsafe; serious effects include hypertension, palpitations, respiratory distress, and—when combined with other stimulants or intense exercise—stroke and cardiac arrest. Huperzine A can cause dose-dependent cholinergic side effects (blurred vision, diarrhea, nausea, sweating).

Black pepper is generally safe as a food spice; concentrated supplements warrant caution. Phenylethylamine has limited human safety data and may affect heart rate and blood pressure.

Side effects, ingredient by ingredient Vitamin B6 Caffeine Cocoa Theacrine Vitamin B12 Rauwolscine Isopropylnorsynephrine Black Pepper

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 10 of the 11 matched ingredients can interact with medications — Huperzine A, Black Pepper, Cocoa, Vitamin B12, Vitamin B6, among others.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; seizure medications; immunosuppressants / transplant drugs; diabetes medications; lithium; Parkinson's medications.
  • For scale: 1,597 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you take Shredded-AF, double-check with your doctor or pharmacist if you're on ephedrine (Major-severity risk of serious cardiovascular events). Check if you take blood-pressure medications, as several ingredients may lower blood pressure further.

If you're on seizure medications, theophylline, heart rhythm drugs, beta-blockers, antiretrovirals, blood thinners, antidepressants, MAOIs, anticholinergic or cholinergic drugs, or barbiturates, confirm it's safe—the interactions are documented and range from moderate to major severity. No interactions are documented for the ingredients we could not check (dynamine, vitamin B9, N-acetyl-L-tyrosine, theophylline anhydrous, LeanGBB, N,N-dimethylphenethylamine, Senactiv, and 3,5 diiodo-L-thyronine).

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

This is a multi-ingredient stimulant and nootropic formula with potent active compounds—especially caffeine, theacrine, and isopropylnorsynephrine—plus several ingredients (alpha yohimbine, phenylethylamine) with limited safety data. If you're on any blood-pressure medications, seizure drugs, heart rhythm drugs, blood thinners, or antidepressants, check your exact medications with your doctor or pharmacist before starting it.

The same goes if you take ephedrine, barbiturates, or any MAOI. Because many ingredients here are poorly studied in long-term use and some are potent stimulants, this product is not suitable for pregnancy, breastfeeding, or anyone with cardiovascular concerns without professional guidance.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 11 of 19 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Aug 23, 2023.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Shredded-AF, straight from the product label.

Brand Steel
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Aug 23, 2023
DSLD ID 300089
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Shredded-AF by Steel, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
30
IngredientAmount% DV
Vitamin B65 mg294%
Caffeine Anhydrous300 mg--
Theobromine50 mg--
Theacrine50 mg--
Dynamine75 mg--
Vitamin B12500 mcg20833%
Vitamin B9400 mcg100%
N-Acetyl-L-Tyrosine150 mg--
Alpha Yohimbine2 mg--
Theophylline Anhydrous40 mg--
N-Isopropylnorsynephrine25 mg--
Black Pepper Fruit Extract5 mg--
Phenylethylamine Hydrochloride250 mg--
Huperzine A10 mg--
LeanGBB15 mg--
Grains of Paradise50 mg--
N, N-Dimethylphenethylamine150 mg--
Senactiv50 mg--
3,5 Diiodo-L-Thyronine150 mcg--

Other ingredients: Gelatin, Magnesium Stearate, Silicon Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formulation

Forged in the U.S.A.

Fat loss Appetite control Energy

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

Dynamine Dynamine is a registered trademark and protected by patents pending, serial no. 61/903,362; under exclusive global distribution by Compound Solutions, Inc. Senactive Senactive is a registered trademark of Nuliv Science USA, Inc.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Shredded-AF by Steel label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Shredded-AF label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Shredded-AF by Steel

These are the 19 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Vitamin B6

Interacts with
210 drugs
5 mg per serving Form: Pyridoxine Hydrochloride

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is b...

Vitamin B6 monograph & interactions

Caffeine Anhydrous

Interacts with
655 drugs
300 mg per serving

Caffeine is a natural stimulant found in coffee, tea, and many other plants and products. In moderate amounts it can boost alertness and reduce tiredn...

Caffeine Anhydrous monograph & interactions

Theobromine

Interacts with
661 drugs
50 mg per serving

Cocoa is rich in plant compounds called flavanols that may modestly support blood vessel function and blood pressure, but most chocolate products are...

Theobromine monograph & interactions

Theacrine

Interacts with
248 drugs
50 mg per serving

Theacrine is a caffeine-like compound found naturally in certain tea plants and is sold in supplements for energy, focus, and mood. Early human studie...

Theacrine monograph & interactions

Dynamine

75 mg per serving Form: Methylliberine

Vitamin B12

Interacts with
20 drugs
500 mcg per serving Form: Methylcobalamin

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very h...

Vitamin B12 monograph & interactions

Vitamin B9

400 mcg per serving Form: Folic Acid

N-Acetyl-L-Tyrosine

150 mg per serving

Alpha Yohimbine

Interacts with
677 drugs
2 mg per serving

Rauwolscine (alpha-yohimbine) is a stimulant alkaloid closely related to yohimbine that is marketed mainly in fat-burning and pre-workout supplements....

Alpha Yohimbine monograph & interactions

Theophylline Anhydrous

40 mg per serving

N-Isopropylnorsynephrine

Interacts with
344 drugs
25 mg per serving

Isopropylnorsynephrine is a synthetic stimulant chemically related to synephrine, marketed mainly in weight-loss and pre-workout supplements. It has v...

N-Isopropylnorsynephrine monograph & interactions

Black Pepper Fruit Extract

Interacts with
1,019 drugs
5 mg per serving

Black pepper is a common kitchen spice that is generally safe in the amounts used in food. Its extract, piperine, is mostly added to supplements to he...

Black Pepper Fruit Extract monograph & interactions

Phenylethylamine Hydrochloride

Interacts with
187 drugs
250 mg per serving

Phenethylamine (PEA) is a natural compound made in the body and found in foods like chocolate; supplements are marketed for mood, focus, and energy. R...

Phenylethylamine Hydrochloride monograph & interactions

Huperzine A

Interacts with
219 drugs
10 mg per serving Form: Huperzia serrata Leaf Extract

Huperzine A is a purified compound from a Chinese clubmoss that acts like a mild cholinesterase inhibitor, similar in mechanism to some prescription A...

Huperzine A monograph & interactions

LeanGBB

15 mg per serving Form: Gamma Butyrobetaine

Grains of Paradise

No known
interactions
50 mg per serving Form: 6-Paradol

Grains of paradise is a West African spice in the ginger family that people use for digestion, as a spice, and more recently in supplements aimed at m...

Grains of Paradise monograph & interactions

N, N-Dimethylphenethylamine

150 mg per serving

Senactiv

50 mg per serving Form: Panax notoginseng extract, Rosa roxburghii extract

3,5 Diiodo-L-Thyronine

150 mcg per serving

Other (inactive) ingredients: Gelatin, Magnesium Stearate, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

Shredded-AF by Steel Drug Interactions

Want to check YOUR meds against Shredded-AF?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
1,596Drugs
8 Major 1,565 Moderate 23 Minor

Ingredients driving the most interactions

Black Pepper Fruit Extract 1,019
Alpha Yohimbine 677
Theobromine 661
Caffeine Anhydrous 655
N-Isopropylnorsynephrine 344

Individual Drug Interactions

The ingredients in Shredded-AF interact with 1,596 drugs. Click any drug to see the details.

10 of the 19 ingredients in Shredded-AF interact with drugs. Each result below shows which ingredient is responsible. Black Pepper Fruit Extract Alpha Yohimbine Theobromine Caffeine Anhydrous N-Isopropylnorsynephrine Theacrine Huperzine A Vitamin B6 Phenylethylamine Hydrochloride Vitamin B12

Each ingredient & the kinds of drugs it affects

For each ingredient in Shredded-AF with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Black Pepper Fruit Extract17 drug types · 1,019 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation. This has not been reported in humans.

Likelihood Possible Evidence D
Antidiabetes Drugs

Theoretically, black pepper might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that piperine, a constituent of black pepper, can reduce blood glucose levels. Monitor blood glucose levels closely. Dose adjustments might be necessary.

Likelihood Possible Evidence D
Atorvastatin (Lipitor)

Theoretically, black pepper might increase blood levels of atorvastatin.
Animal research shows that taking piperine, a constituent of black pepper, 35 mg/kg can increase the maximum serum concentration of atorvastatin three-fold. This has not been reported in humans.

Likelihood Possible Evidence D
Cyclosporine (Neoral, Sandimmune)

Theoretically, black pepper might increase the effects and side effects of cyclosporine.
In vitro research shows that piperine, a constituent of black pepper, increases the bioavailability of cyclosporine. This has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.
In vitro research suggests that some constituents of black pepper inhibit CYP2D6. This has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, black pepper might increase levels of drugs metabolized by CYP3A4.
In vitro research and pharmacokinetic simulation data suggest that piperine, a constituent of black pepper, as well as the pepper fruit seem to inhibit CYP3A4. This has not been reported in humans.

Likelihood Possible Evidence D
Lithium

Theoretically, black pepper might increase blood levels of lithium due to its diuretic effects. The dose of lithium might need to be reduced.
Black pepper is thought to have diuretic properties.

Likelihood Probable Evidence D
Nevirapine (Viramune)

Black pepper might increase blood levels of nevirapine.
Clinical research shows that piperine, a constituent of black pepper, increases the plasma concentration of nevirapine. However, no adverse effects were observed in this study.

Likelihood Probable Evidence D
P-Glycoprotein Substrates

Theoretically, black pepper might increase levels of P-glycoprotein substrates.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit P-glycoprotein.

Likelihood Possible Evidence D
Pentobarbital (Nembutal)

Theoretically, black pepper might increase the sedative effects of pentobarbital.
Animal research shows that piperine, a constituent of black pepper, increases pentobarbital-induced sleeping time.

Likelihood Possible Evidence D
Phenytoin (Dilantin)

Black pepper might increase blood levels of phenytoin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption, slow elimination, and increase levels of phenytoin. Taking a single dose of black pepper 1 gram along with phenytoin seems to double the serum concentration of phenytoin. Consuming a soup with black pepper providing piperine 44 mg/200 mL of soup along with phenytoin also seems to increase phenytoin levels when compared with consuming the same soup without black pepper.

Likelihood Possible Evidence B
Propranolol (Inderal)

Black pepper might increase blood levels of propranolol.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of propranolol.

Likelihood Possible Evidence B
Rifampin (Rifadin)

Black pepper might increase blood levels of rifampin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and serum levels of rifampin.

Likelihood Possible Evidence B
Theophylline

Black pepper might increase blood levels of theophylline.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of theophylline.

Likelihood Possible Evidence D
Amoxicillin (Amoxil, Trimox)

Theoretically, black pepper might increase the effects and side effects of amoxicillin.
Animal research shows that taking piperine, a constituent of black pepper, with amoxicillin increases plasma levels of amoxicillin. This has not been reported in humans.

Likelihood Possible Evidence D
Carbamazepine (Tegretol)

Theoretically, black pepper might increase blood levels of carbamazepine, potentially increasing the effects and side effects of carbamazepine.
One clinical study in patients taking carbamazepine 300 mg or 500 mg twice daily shows that taking a single 20 mg dose of purified piperine, a constituent of black pepper, increases carbamazepine levels. Piperine may increase carbamazepine absorption by increasing blood flow to the GI tract, increasing the surface area of the small intestine, or inhibiting cytochrome P450 3A4 (CYP3A4) in the gut wall. Absorption was significantly increased by 7-10 mcg/mL/hour. The time to eliminate carbamazepine was also increased by 4-8 hours. Although carbamazepine levels were increased, this did not appear to increase side effects. In vitro research also shows that piperine can increase carbamazepine levels by 11% in a time-dependent manner.

Likelihood Possible Evidence B
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, black pepper might decrease levels and clinical effects of drugs metabolized by CYP1A2.
In vitro research suggests that black pepper induces CYP1A2. This has not been reported in humans.

Likelihood Possible Evidence D
Black Pepper Fruit Extract full monograph & interactions

Alpha Yohimbine6 drug types · 677 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, rauwolscine may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Rauwolscine is structurally related to yohimbine. In vitro research shows that yohimbine inhibits platelet aggregation.

Likelihood Possible Evidence D
Calcium Channel Blockers

Theoretically, rauwolscine may have additive coronary vasodilatory effects if used with calcium channel blockers.
In vitro, rauwolscine inhibits calcium influx in aortic smooth muscle cells.

Likelihood Possible Evidence D
Clonidine (Catapres)

Theoretically, rauwolscine may inhibit the effects of clonidine.
In animal research, rauwolscine antagonized the effects of clonidine.

Likelihood Possible Evidence D
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, rauwolscine might increase levels of drugs metabolized by CYP2D6.
Rauwolscine is structurally related to yohimbine. In vitro research shows that yohimbine inhibits CYP2D6 enzyme activity.

Likelihood Possible Evidence D
Seizure Threshold Lowering Drugs

Theoretically, taking rauwolscine with seizure threshold lowering drugs might increase the risk of adverse convulsant effects.
In animal research, intraperitoneal rauwolscine lowered the seizure threshold level of the drug metrazol.

Likelihood Possible Evidence D
Stimulant Drugs

Theoretically, taking rauwolscine with stimulant drugs might increase the risk of adverse stimulant effects.
Rauwolscine has demonstrated stimulant effects in animal research.

Likelihood Possible Evidence D
Alpha Yohimbine full monograph & interactions

Theobromine37 drug types · 661 drugs

Ace Inhibitors (Aceis)

Theoretically, taking cocoa with ACEIs might increase the risk of adverse effects.
Human research shows that dark chocolate can inhibit ACE. Additionally, prolonged angioedema in an elderly patient on an ACE inhibitor was precipitated with intake of diabetic chocolate.

Likelihood Possible Evidence D
Adenosine (Adenocard)

Theoretically, cocoa might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Cocoa contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole than adenosine-induced stress testing.

Likelihood Possible Evidence B
Alcohol (Ethanol)

Theoretically, concomitant use might increase levels and adverse effects of caffeine.
Cocoa contains caffeine. Alcohol reduces caffeine metabolism. Concomitant use of alcohol can increase caffeine serum concentrations and the risk of caffeine adverse effects.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, cocoa may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Clinical research shows that intake of cocoa can inhibit platelet adhesion, aggregation, and activity and increase aspirin-induced bleeding time. For patients on dual antiplatelet therapy, cocoa may enhance the inhibitory effect of clopidogrel, but not aspirin, on platelet aggregation.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, taking cocoa with antihypertensive drugs might increase the risk of hypotension.
Clinical research shows that cocoa can modestly decrease blood pressure in hypertensive and normotensive patients.

Likelihood Possible Evidence D
Beta-Adrenergic Agonists

Theoretically, large amounts of cocoa might increase the cardiac inotropic effects of beta-agonists.
Cocoa contains caffeine. Theoretically, large amounts of caffeine might increase cardiac inotropic effects of beta-agonists. A case of atrial fibrillation associated with consumption of large quantities of chocolate in a patient with chronic albuterol inhalation abuse has also been reported.

Likelihood Probable Evidence D
Cytochrome P450 1A2 (Cyp1A2) Inhibitors

Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
Cocoa contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2),. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from cocoa and increase caffeine levels.

Likelihood Possible Evidence D
Dipyridamole (Persantine)

Theoretically, cocoa might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Cocoa contains caffeine. Caffeine may inhibit dipyridamole-induced vasodilation. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole than adenosine-induced stress testing.

Likelihood Probable Evidence B
Disulfiram (Antabuse)

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
Cocoa contains caffeine. In human research, disulfiram decreases the rate of caffeine clearance.

Likelihood Probable Evidence B
Diuretic Drugs

Theoretically, using cocoa with diuretic drugs might increase the risk of hypokalemia.
Cocoa contains caffeine. In excessive amounts, caffeine can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Likelihood Possible Evidence D
Ephedrine

Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Cocoa contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.

Likelihood Possible Evidence D
Estrogens

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Cocoa contains caffeine. Estrogen inhibits caffeine metabolism.

Likelihood Probable Evidence B
Flutamide (Eulexin)

Theoretically, cocoa might increase the levels and adverse effects of flutamide.
Cocoa contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide.

Likelihood Possible Evidence D
Fluvoxamine (Luvox)

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Cocoa contains caffeine. Fluvoxamine reduces caffeine metabolism.

Likelihood Probable Evidence D
Lithium

Theoretically, abrupt cocoa withdrawal might increase the levels and adverse effects of lithium.
Cocoa contains caffeine. There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal.

Likelihood Possible Evidence D
Monoamine Oxidase Inhibitors (Maois)

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Cocoa contains caffeine. Large amounts of caffeine with MAOIs might precipitate a hypertensive crisis.

Likelihood Possible Evidence D
Nicotine

Theoretically, concomitant use might increase the risk of hypertension.
Cocoa contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly.

Likelihood Probable Evidence B
Pentobarbital (Nembutal)

Theoretically, cocoa might decrease the effects of pentobarbital.
Cocoa contains caffeine. Caffeine might negate the hypnotic effects of pentobarbital.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

Theoretically, cocoa might reduce the effects of phenobarbital and increase the risk for convulsions.
Cocoa contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital. The exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Phenylpropanolamine

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Cocoa contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Likelihood Probable Evidence B
Phenytoin (Dilantin)

Theoretically, cocoa might reduce the effects of phenytoin and increase the risk for convulsions.
Cocoa contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin. The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Quinolone Antibiotics

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
Cocoa contains caffeine. Quinolones (also referred to as fluoroquinolones) decrease caffeine clearance.

Likelihood Probable Evidence B
Riluzole (Rilutek)

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Cocoa contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2, and concomitant use might reduce metabolism of one or both agents.

Likelihood Possible Evidence D
Stimulant Drugs

Theoretically, concomitant use might increase stimulant adverse effects.
Cocoa contains caffeine. Concomitant use might increase the risk of stimulant adverse effects.

Likelihood Probable Evidence C
Theophylline

Theoretically, cocoa might increase the levels and adverse effects of theophylline.
Cocoa contains caffeine. Large amounts of caffeine might inhibit theophylline metabolism. Caffeine decreases theophylline clearance 23% to 29%.

Likelihood Probable Evidence B
Theobromine full monograph & all 37 interactions

Caffeine Anhydrous41 drug types · 655 drugs

Ephedrine

Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.

Likelihood Probable Evidence D
Adenosine (Adenocard)

Theoretically, caffeine might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Some evidence shows that caffeine is a competitive inhibitor of adenosine and can reduce the vasodilatory effects of adenosine in humans. However, other research shows that caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Likelihood Possible Evidence B
Anticoagulant/Antiplatelet Drugs

Theoretically, caffeine may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Caffeine is reported to have antiplatelet activity. Theoretically, it might increase the risk of bleeding when used concomitantly with these agents; however, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Beta-Adrenergic Agonists

Theoretically, large amounts of caffeine might increase the cardiac inotropic effects of beta-agonists.

Likelihood Probable Evidence D
Carbamazepine (Tegretol)

Theoretically, caffeine might reduce the effects of carbamazepine and increase the risk for convulsions.
Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg. Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals.

Likelihood Possible Evidence D
Cimetidine (Tagamet)

Theoretically, cimetidine might increase the levels and adverse effects of caffeine.
Cimetidine decreases the rate of caffeine clearance by 31% to 42%.

Likelihood Likely Evidence B
Clozapine (Clozaril)

Caffeine might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Caffeine might increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism. Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Although researchers speculate that caffeine might inhibit CYP1A2, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients more sensitive to an interaction between clozapine and caffeine. In one case report, severe, life-threatening clozapine toxicity and multiorgan system failure occurred in a patient with schizophrenia stabilized on clozapine who consumed caffeine 600 mg daily.

Likelihood Possible Evidence B
Dipyridamole (Persantine)

Theoretically, caffeine might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Caffeine inhibits dipyridamole-induced vasodilation. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Likelihood Probable Evidence B
Disulfiram (Antabuse)

Theoretically, disulfiram use might increase the levels and adverse effects of caffeine.
Disulfiram decreases the rate of caffeine clearance.

Likelihood Probable Evidence B
Diuretic Drugs

Theoretically, using caffeine with diuretic drugs might increase the risk of hypokalemia.
Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Likelihood Possible Evidence D
Estrogens

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Estrogen inhibits caffeine metabolism.

Likelihood Probable Evidence B
Ethosuximide (Zarontin)

Theoretically, caffeine might reduce the effects of ethosuximide and increase the risk for convulsions.
Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide. However, this effect has not been reported in humans.

Likelihood Possible Evidence D
Felbamate (Felbatol)

Theoretically, caffeine might reduce the effects of felbamate and increase the risk for convulsions.
Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate. However, this effect has not been reported in humans.

Likelihood Possible Evidence D
Flutamide (Eulexin)

Theoretically, caffeine might increase the levels and adverse effects of flutamide.
In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide. However, this effect has not been reported in humans.

Likelihood Probable Evidence D
Fluvoxamine (Luvox)

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Fluvoxamine reduces caffeine metabolism.

Likelihood Probable Evidence D
Lithium

Abrupt caffeine withdrawal might increase the levels and adverse effects of lithium.
Caffeine has diuretic activity. When abruptly discontinued, caffeine may alter the clearance of lithium. There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal and 6 case reports of elevated serum lithium levels after reducing or eliminating caffeine intake. In one case, a male with schizoaffective disorder stabilized on lithium had an elevated lithium level after reducing his caffeine intake by 87%. At a later date, he increased his caffeine intake by 6-fold, resulting in a subtherapeutic lithium level and a recurrence of psychiatric symptoms.

Likelihood Probable Evidence D
Monoamine Oxidase Inhibitors (Maois)

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies. Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis. In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension. Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

Likelihood Possible Evidence D
Nicotine

Theoretically, concomitant use might increase the risk of hypertension.
Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly.

Likelihood Probable Evidence B
Pentobarbital (Nembutal)

Theoretically, caffeine might decrease the effects of pentobarbital.
Caffeine might negate the hypnotic effects of pentobarbital.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

Theoretically, caffeine might reduce the effects of phenobarbital and increase the risk for convulsions.
Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital. However, the exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Phenylpropanolamine

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Likelihood Probable Evidence B
Phenytoin (Dilantin)

Theoretically, caffeine might reduce the effects of phenytoin and increase the risk for convulsions.
Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin. The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Pioglitazone (Actos)

Theoretically, caffeine might increase the levels and clinical effects of pioglitazone.
Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone. However, the exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Quinolone Antibiotics

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
Quinolones (also called fluoroquinolones) can decrease caffeine clearance by inhibiting cytochrome P450 1A2 (CYP1A2) enzyme.

Likelihood Probable Evidence B
Riluzole (Rilutek)

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents.

Likelihood Possible Evidence D
Caffeine Anhydrous full monograph & all 41 interactions

N-Isopropylnorsynephrine2 drug types · 344 drugs

Antihypertensive Drugs

Theoretically, isopropylnorsynephrine might decrease the effects of antihypertensive drugs.
In vitro research shows that isopropylnorsynephrine is a highly selective, direct-acting beta-adrenergic receptor agonist with positive chronotropic effects, and hypertension has been reported in patients taking combination products containing isopropylnorsynephrine and other stimulants.

Likelihood Possible Evidence D
Stimulant Drugs

Theoretically, taking isopropylnorsynephrine with stimulant drugs might have additive effects and increase the risk of adverse cardiovascular effects.
Isopropylnorsynephrine is an investigational beta-agonist and a derivative of synephrine and octopamine, which are stimulant constituents of bitter orange. In vitro research shows that isopropylnorsynephrine is a highly selective, direct-acting beta-adrenergic receptor agonist with positive chronotropic effects. Theoretically, isopropylnorsynephrine may also have stimulant effects.

Likelihood Possible Evidence D
N-Isopropylnorsynephrine full monograph & interactions

Theacrine1 drug type · 248 drugs

Cns Depressants

Theoretically, theacrine might alter the effects of CNS depressants.
Animal research shows that low doses of theacrine have sedating effects, whereas high doses might have stimulant effects. Depending on the dose of theacrine used, it might increase or decrease the effects of CNS depressants. However, these effects have not yet been reported in humans.

Likelihood Possible Evidence D
Theacrine full monograph & interactions

Huperzine A2 drug types · 219 drugs

Anticholinergic Drugs

Theoretically, huperzine A might decrease the effects of anticholinergic drugs.
Huperzine A has acetylcholinesterase (AChE) inhibiting effects. In animal models, huperzine A reversed cognitive deficits induced by scopolamine, an anticholinergic drug.

Likelihood Possible Evidence D
Cholinergic Drugs

Theoretically, concurrent use of huperzine A with cholinergic drugs might increase the effects and side effects of these medications.
Huperzine A can inhibit acetylcholinesterase (AChE) and might cause cumulative effects if used with cholinergic drugs.

Likelihood Possible Evidence B
Huperzine A full monograph & interactions

Vitamin B65 drug types · 210 drugs

Amiodarone (Cordarone)

Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.
Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect.

Likelihood Possible Evidence B
Antihypertensive Drugs

Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.
Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure. Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Phenytoin (Dilantin)

High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Levodopa

Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.
Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people.

Likelihood Unlikely Evidence D
Vitamin B6 full monograph & interactions

Phenylethylamine Hydrochloride2 drug types · 187 drugs

Monoamine Oxidase Inhibitors (Maois)

Theoretically, taking phenethylamine concomitantly with MAOIs may increase adverse effects.
In humans, phenethylamine is oxidized by MAO-B to form the inactive metabolite phenylacetic acid. Animal research shows that administering an MAOI prior to phenethylamine increases the amphetamine-like effects of phenethylamine. However, low-quality clinical research has used phenethylamine with selegiline, an MAOI, with apparent safety.

Likelihood Possible Evidence D
Serotonergic Drugs

Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of serotonergic adverse effects.
Animal research shows that phenethylamine increases levels of serotonin, norepinephrine, and dopamine. Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of additive serotonergic adverse effects, including serotonin syndrome and cerebral vasoconstrictive disorders. However, low-quality clinical research has used phenethylamine with selegiline, a monoamine oxidase inhibitor (MAOI), with apparent safety.

Likelihood Possible Evidence D
Phenylethylamine Hydrochloride full monograph & interactions

Vitamin B121 drug type · 20 drugs

Metformin (Glucophage)

Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals. Prolonged use of metformin can interfere with the absorption of B12 in the digestive system, potentially leading to a deficiency in this essential vitamin.

Likelihood Possible Evidence A
Vitamin B12 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Shredded-AF, from the product label.

Steel

Name
Steel Supplements
Pharmacist Counseling Corner

Shredded-AF by Steel: Common Questions

Does Shredded-AF by Steel interact with any medications?
Yes. Based on its ingredients, Shredded-AF has a known interaction with 1,596 medications, including 8 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Shredded-AF contains 19 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm pregnant or breastfeeding?
No—safety data is insufficient or missing for most of these ingredients during pregnancy and breastfeeding. Theacrine, alpha yohimbine, isopropylnorsynephrine, huperzine A, phenylethylamine, and grains of paradise all lack safety information for pregnancy and lactation. Vitamin B12 is considered safe during both, but the product as a whole is not recommended. Talk with your doctor before considering it.
What does huperzine A do?
Huperzine A is a compound that inhibits an enzyme that breaks down acetylcholine, a brain chemical involved in memory and thinking. It's possibly effective for Alzheimer disease, but evidence for cognitive function and memory in healthy people is insufficient. It can cause cholinergic side effects like nausea, diarrhea, and blurred vision.
Is the caffeine content a problem if I'm sensitive to stimulants?
Yes. This product combines multiple stimulants—caffeine anhydrous, theacrine, theobromine, alpha yohimbine, isopropylnorsynephrine, and phenylethylamine—which can amplify effects like jitteriness, anxiety, insomnia, and heart palpitations. If you're sensitive to caffeine or have any heart concerns, this product is not for you.
Why is there black pepper in a fat-loss formula?
Black pepper fruit extract (piperine) is included to enhance the absorption of other ingredients in the formula. However, it can increase blood levels of many drugs, which is why it's important to check it with your medications.
Is vitamin B6 in this safe at high doses?
Not long-term. Vitamin B6 is well tolerated at normal amounts, but high doses over extended periods can cause sensory neuropathy (nerve damage), especially above 1,000 mg daily. This product contains B6, so if you're taking other B6 supplements, keep total intake in mind.
What is theacrine and is it safe?
Theacrine is a compound structurally similar to caffeine that acts as a stimulant. Short-term use appears generally well tolerated in studies, but long-term safety is not established. It interacts with CNS depressants (sedatives, sleep aids) and may increase or decrease their effects depending on the dose used.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Shredded-AF label
Go deeper

The Full Monographs Behind Shredded-AF’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Vitamin B6

Interacts with 210 drugs

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is best known for helping with pregnancy-rel...

Read the full Vitamin B6 monograph → Herb & supplement monograph

Caffeine

Interacts with 655 drugs

Caffeine is a natural stimulant found in coffee, tea, and many other plants and products. In moderate amounts it can boost alertness and reduce tiredness for most healthy adults, but too muc...

Read the full Caffeine monograph → Herb & supplement monograph

Cocoa

Interacts with 661 drugs

Cocoa is rich in plant compounds called flavanols that may modestly support blood vessel function and blood pressure, but most chocolate products are high in sugar, fat, and calories, which...

Read the full Cocoa monograph → Herb & supplement monograph

Theacrine

Interacts with 248 drugs

Theacrine is a caffeine-like compound found naturally in certain tea plants and is sold in supplements for energy, focus, and mood. Early human studies suggest it may give a stimulant-like b...

Read the full Theacrine monograph → Herb & supplement monograph

Vitamin B12

Interacts with 20 drugs

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very helpful for people who are deficient — su...

Read the full Vitamin B12 monograph → Herb & supplement monograph

Rauwolscine

Interacts with 677 drugs

Rauwolscine (alpha-yohimbine) is a stimulant alkaloid closely related to yohimbine that is marketed mainly in fat-burning and pre-workout supplements. Human evidence for its benefits is very...

Read the full Rauwolscine monograph → Herb & supplement monograph

Isopropylnorsynephrine

Interacts with 344 drugs

Isopropylnorsynephrine is a synthetic stimulant chemically related to synephrine, marketed mainly in weight-loss and pre-workout supplements. It has very little human safety or effectiveness...

Read the full Isopropylnorsynephrine monograph → Herb & supplement monograph

Black Pepper

Interacts with 1,019 drugs

Black pepper is a common kitchen spice that is generally safe in the amounts used in food. Its extract, piperine, is mostly added to supplements to help the body absorb other ingredients (li...

Read the full Black Pepper monograph → Herb & supplement monograph

Phenethylamine (pea)

Interacts with 187 drugs

Phenethylamine (PEA) is a natural compound made in the body and found in foods like chocolate; supplements are marketed for mood, focus, and energy. Reliable human research on the supplement...

Read the full Phenethylamine (pea) monograph → Herb & supplement monograph

Huperzine A

Interacts with 219 drugs

Huperzine A is a purified compound from a Chinese clubmoss that acts like a mild cholinesterase inhibitor, similar in mechanism to some prescription Alzheimer's drugs. Some small studies sug...

Read the full Huperzine A monograph → Herb & supplement monograph

Grains Of Paradise

Grains of paradise is a West African spice in the ginger family that people use for digestion, as a spice, and more recently in supplements aimed at metabolism. Early human research suggests...

Read the full Grains Of Paradise monograph →
Sources

Sources & How We Checked

Shredded-AF's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 502 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Vitamin B6 32 references
  1. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  2. Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: The new basis for recommendations for calcium and related nutrients, B vitamins, and choline. J Am Diet Assoc 1998;98:699-706. PubMed
  3. Geerling BJ, Dagnelie PC, Badart-Smook A, et al. Diet as a risk factor for the development of ulcerative colitis. Am J Gastroenterol 2000;95:1008-13. PubMed
  4. South M. Neonatal seizures after pyridoxine use -- reply. Lancet 1999;354:2083. PubMed
  5. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
  6. Baxter P, Aicardi J. Neonatal seizures after pyridoxine use. Lancet 1999;354:2082-3. PubMed
  7. Bendich A, Cohen M. Vitamin B6 safety issues. Ann N Y Acad Sci 1990;585:321-30.
  8. Schaumburg H, Kaplan J, Windebank A. Sensory neuropathy from pyridoxine abuse. A new megavitamin syndrome. N Engl J Med 1983;309:445-8. PubMed
  9. Gordon N. Pyridoxine dependency: an update. Dev Med Child Neurol 1997;39:63-5. PubMed
  10. Lewis PJ. Pain in the hand and wrist. Pyridoxine supplements may help patients with carpal tunnel syndrome. BMJ 1995;310:1534. PubMed
  11. Kaufman G. Pyridoxine against amiodarone-induced photosensitivity (letter). Lancet 1984;1:51-2. PubMed
  12. Mulrow JP, Mulrow CD, McKenna WJ. Pyridoxine and amiodarone-induced photosensitivity. Ann Intern Med 1985;103:68-9. PubMed
  13. Kawada A, Kashima A, Shiraishi H, et al. Pyridoxine-induced photosensitivity and hypophosphatasia. Dermatology 2000;201:356-60.. PubMed
  14. Vasile A, Goldberg R, Kornberg B. Pyridoxine toxicity: report of a case. J Am Osteopath Assoc 1984;83:790-1. DOI
  15. Hansson O, Sillanpaa M. Pyridoxine and serum concentration of phenytoin and phenobarbitone. Lancet 1976;1:256. DOI
  16. Jansen T, Romiti R, Kreuter A, Altmeyer P. Rosacea fulminans triggered by high-dose vitamins B6 and B12. J Eur Acad Dermatol Venereol 2001;15:484-5..
  17. Chittumma P, Kaewkiattikun K, Wiriyasiriwach B. Comparison of the effectiveness of ginger and vitamin B6 for treatment of nausea and vomiting in early pregnancy: a randomized double-blind controlled trial. J Med Assoc Thai 2007;90:15-20.
  18. Hatzitolios, A., Iliadis, F., Katsiki, N., and Baltatzi, M. Is the anti-hypertensive effect of dietary supplements via aldehydes reduction evidence based? A systematic review. Clin Exp.Hypertens. 2008;30(7):628-639. PubMed
  19. Vasdev, S., Ford, C. A., Parai, S., Longerich, L., and Gadag, V. Dietary vitamin B6 supplementation attenuates hypertension in spontaneously hypertensive rats. Mol.Cell Biochem. 1999;200(1-2):155-162.
  20. de, Vogel S., Dindore, V., van, Engeland M., Goldbohm, R. A., van den Brandt, P. A., and Weijenberg, M. P. Dietary folate, methionine, riboflavin, and vitamin B-6 and risk of sporadic colorectal cancer. J Nutr 2008;138(12):2372-2378. PubMed
  21. Hagen, I., Nesheim, B. I., and Tuntland, T. No effect of vitamin B-6 against premenstrual tension. A controlled clinical study. Acta Obstet.Gynecol.Scand. 1985;64(8):667-670. PubMed
  22. Aybak, M., Sermet, A., Ayyildiz, M. O., and Karakilcik, A. Z. Effect of oral pyridoxine hydrochloride supplementation on arterial blood pressure in patients with essential hypertension. Arzneimittelforschung. 1995;45(12):1271-1273.
  23. Lal, K. J., Dakshinamurti, K., and Thliveris, J. The effect of vitamin B6 on the systolic blood pressure of rats in various animal models of hypertension. J Hypertens. 1996;14(3):355-363. PubMed
  24. Lauritzen CH, Reuter HD, Repges R, Bohnert K, and Schmidt U. Treatment of premenstrual tension syndrome with Vitex agnus castus. Controlled, double-blind study versus pyridoxine. Phytomed 1997;4(3):183-189. PubMed
  25. Fonseca VA, Lavery LA, Thethi TK, et al. Metanx in type 2 diabetes with peripheral neuropathy: A randomized trial. Am J Med 2013;126(2):141-9. PubMed
  26. Hankey GJ, Eikelboom JW, Yi Q, et al. Treatment with B vitamins and incidence of cancer in patients with previous stroke or transient ischemic attack: Results of a randomized placebo-controlled trial. Stroke 2012;43(6):1572-7. PubMed
  27. Hoyer-Kuhn H, Kohbrok S, Volland R, Franklin J, Hero B, Beck BB, Hoppe B. Vitamin B6 in primary hyperoxaluria I: first prospective trial after 40 years of practice. Clin J Am Soc Nephrol. 2014 Mar;9(3):468-77. PubMed
  28. Mahmoud A, Tabassum S, Al Enazi S, et al. Amelioration of levetiracetam-induced behavioral side effects by pyridoxine. A randomized double blind controlled study. Pediatr Neurol 2021;119:15-21. PubMed
  29. Gupta M, Gallante B, Bamberger JN, et al. Prospective randomized evaluation of idiopathic hyperoxaluria treatments. J Endourol 2021;35(12):1844-1851. PubMed
  30. Li H, Chen M, Liang S, et al. Excessive vitamin B6 during treatment is related to poor prognosis of patients with nasopharyngeal carcinoma: A U-shaped distribution suggests low dose supplement. Clin Nutr 2021;40(4):2293-2300. PubMed
  31. Tanigawa J, Nabatame S, Tominaga K, et al. High-dose pyridoxine treatment for inherited glycosylphosphatidylinositol deficiency. Brain Dev 2021;43(6):680-687. PubMed
  32. Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin No. 189: Nausea And Vomiting Of Pregnancy. Obstet Gynecol. 2018;131(1):e15-e30. PubMed

See these in context on the Vitamin B6 monograph →

Caffeine 236 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. PubMed
  3. Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. PubMed
  4. Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. PubMed
  5. Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. PubMed
  6. Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3.
  7. Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. PubMed
  8. Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
  9. Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed
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See these in context on the Caffeine monograph →

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Black Pepper 29 references
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Grains Of Paradise 2 references
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DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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