Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

XS Energy + Focus Ingredients & Drug Interactions

by Nutrilite

XS Energy + Focus label
See full label image
Tablet Or Pill Category: Other Combinations
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking XS Energy + Focus 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

XS Energy + Focus is a dietary supplement by Nutrilite with 5 active ingredients. Its ingredients are commonly taken for fatigue and low energy, stress and coping (adaptogen), mental performance and focus.Based on those ingredients, 1,495 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Rhodiola rosea, Caffeine, Vitamin C. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against XS Energy + Focus by Nutrilite

Ask about any prescription or over-the-counter medication and we check it for interactions with XS Energy + Focus by Nutrilite — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of XS Energy + Focus by Nutrilite

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 Jul 11, 2026

What’s inside

Partial disclosure
Ingredient Transparency · database check
Partial

Most active ingredients list an amount, but at least one is hidden in a blend or missing.

Why this rating?
  • The label discloses an exact amount for 4 of its 7 active ingredients.
  • “Acerola Concentrate Proprietary Blend” is a proprietary blend — the label gives one combined amount (50 mg) without saying how much of each component you get.

XS Energy + Focus contains seven active ingredients. Acerola cherry extract and vitamin C both supply vitamin C for immune support.

Rhodiola rosea is an adaptogen used traditionally to support mental focus and stress resilience. Caffeine is the main stimulant for energy and alertness.

Spinach dehydrate adds micronutrients. Silicon dioxide supports bone health.

The product also contains inactive ingredients (dextrose, cellulose, crospovidone, methylcellulose, stearic acid, glycerin, magnesium stearate, and carnauba wax) that serve as fillers, binders, and capsule coatings.

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: maximize physical endurance and mental focus.
  • We looked for evidence on: Athletic performance, Chronic fatigue syndrome (CFS), Fatigue, Cognitive function, Age-related cognitive decline, Exercise-induced muscle soreness — and 4 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: Spinach is rated "Insufficient Reliable Evidence To Rate" for Cognitive function.

Caffeine is well-established to boost mental alertness and athletic performance. Vitamin C is effective for preventing vitamin C deficiency and possibly effective for anemia of chronic disease, atrial fibrillation, cataracts, and exercise-related respiratory infections.

Acerola cherry extract is possibly effective for vitamin C deficiency. Silicon dioxide is possibly effective for osteoporosis but the evidence for hair loss and gum health is insufficient.

For rhodiola, spinach, and the overall 'focus' claim of the product, we don't have established effectiveness data on file.

The evidence, ingredient by ingredient Rhodiola Vitamin C Acerola Silicon Caffeine Spinach

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 6 of the 6 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 6 of 6.
  • General safety write-ups exist for 6 of 6.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Caffeine is generally well tolerated in moderate amounts for healthy adults, though high doses can cause anxiety, insomnia, tremors, nausea, and rarely stroke. Vitamin C is safe at normal doses but can cause stomach upset, nausea, and diarrhea above 2,000 mg daily, and may increase kidney stone risk in susceptible people.

Acerola is generally safe in food amounts; concentrated supplements have less-studied safety. A small number of people report allergy-like reactions (rash, breathing trouble) to acerola.

Rhodiola is generally well tolerated for short-term use but may cause dizziness or dry mouth; long-term safety is not well studied. Silicon dioxide from food and supplements is well tolerated, though high-dose or long-term safety is not established.

Spinach is safe as a food. Pregnancy and breastfeeding safety varies by ingredient: vitamin C is likely safe at normal amounts (avoid high-dose supplements), rhodiola should be avoided (not enough data), silicon dioxide should be avoided in pregnancy and breastfeeding, and spinach as food is safe.

There is not enough data on file for acerola, caffeine, or spinach dehydrate during pregnancy and breastfeeding—talk to your doctor.

Side effects, ingredient by ingredient Rhodiola Vitamin C Acerola Silicon Caffeine Spinach

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?
  • 5 of the 6 matched ingredients can interact with medications — Spinach, Acerola, Rhodiola, Caffeine, Vitamin C.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; cancer treatments; diabetes medications; lithium.
  • For scale: 1,496 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 this, check if you're on ephedrine (Major risk). Also check for blood thinners like warfarin, blood pressure medications, diabetes drugs, seizure medications (phenobarbital, carbamazepine), barbiturates for sleep, quinolone antibiotics, dipyridamole, clozapine, cimetidine, chemotherapy drugs, estrogen-based birth control or hormone therapy, levothyroxine, indinavir, fluphenazine, losartan, or immunosuppressants.

No interactions are documented for maltodextrin, which we could not check.

Check your own medication Run your meds through the checker above

The bottom line

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

This product is designed for people seeking daytime energy and mental focus, but the caffeine content and multiple drug interactions mean it's not for everyone. If you take any prescription medications—especially blood thinners, diabetes or blood pressure drugs, seizure medications, birth control, thyroid hormone, or psychiatric drugs—check with your pharmacist first.

Avoid it with ephedrine. Pregnant or breastfeeding people should discuss it with their doctor.

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

Assessment coverage: 6 of 7 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Apr 22, 2021.

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 XS Energy + Focus, straight from the product label.

Brand Nutrilite
Barcode (UPC) 123842
Net contents 20 Packet(s)
Market status On market
Date entered into DSLD Apr 22, 2021
DSLD ID 246458
Product type Other Combinations
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, Halal
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 XS Energy + Focus by Nutrilite, 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:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
Servings per container
20
UPC/BARCODE
123842
IngredientAmount% DV
Maltodextrin0 NP--
Silicon Dioxide0 NP--
Acerola Cherry extract0 NP--
Rhodiola rosea100 mg--
Vitamin C30 mg33%
Acerola Concentrate Proprietary Blend50 mg--
Caffeine75 mg--
Spinach dehydrate50 mg--

Other ingredients: Dextrose, Microcystalline Cellulose, Crospovidone, Hydroxypropyl Methylcellulose, Stearic Acid, Glycerin, Magnesium Stearate, Carnauba wax

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.
Formula

Each packet contains the following: (packet shown is not actual size) XS Energy + Focus Helps maximize physical endurance and mental focus.

Star-K (Kosher)

Crescent M (Halal)

General Statements

Try other Nutrilite Packs: Immunity Pack Women's Pack Men's Pack

Exclusively from Amway

Formulation

Stay sharp and fight fatigue

No artificial colors No artificial flavors No preservatives

Nutrilite is the only brand to grow, harvest, and process plants on our own certified organic farms. Source: Euromonitor International Limited; www.euromonitor.com/amway-claims.

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

1 Packet, 1-2x a day

Suggested Use: Take contents of one packet, preferably with a meal. Take up to twice per day, as needed.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Precautions

Children under 12 years of age, pregnant women or nursing mothers, or anyone with a medical condition should consult with a physician before using this product. Keep out of reach of children.

Children under 12 years of age, pregnant women or nursing mothers, or anyone with a medical condition should consult with a physician before using this product.

Storage

Store in a cool, dry place.

Brand IP Statement(s)

Alticor Inc.

Seals/Symbols

Star-K (Kosher) Crescent M (Halal)

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

See for yourself

XS Energy + Focus by Nutrilite label

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

XS Energy + Focus 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 XS Energy + Focus by Nutrilite

These are the 5 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container20 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.

Rhodiola rosea

Interacts with
1,271 drugs
100 mg per serving

Rhodiola is an herb traditionally used to fight fatigue and help the body cope with stress. Some small studies suggest it may modestly reduce fatigue...

Rhodiola rosea monograph & interactions

Vitamin C

Interacts with
207 drugs
30 mg per serving Form: Acerola concentrate, Ascorbic Acid

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for im...

Vitamin C monograph & interactions

Acerola Concentrate Proprietary Blend

Interacts with
128 drugs
50 mg per serving

Acerola is a small tropical fruit prized for its very high natural vitamin C content, and it is mostly used as a food-based source of vitamin C and an...

Acerola Concentrate Proprietary Blend monograph & interactions

Caffeine

Interacts with
655 drugs
75 mg per serving Form: Green Tea extract

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 monograph & interactions

Spinach dehydrate

Interacts with
88 drugs
50 mg per serving

Spinach is a nutrient-dense leafy green that is a healthy part of a balanced diet, providing vitamins, minerals, fiber, and antioxidants. While it is...

Spinach dehydrate monograph & interactions

Other (inactive) ingredients: Dextrose, Microcystalline Cellulose, Crospovidone, Hydroxypropyl Methylcellulose, Stearic Acid, Glycerin, Magnesium Stearate, Carnauba wax. These complete the product’s ingredient list but are not active constituents.

Interaction report

XS Energy + Focus by Nutrilite Drug Interactions

Want to check YOUR meds against XS Energy + Focus?

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
1,495Drugs
8 Major 994 Moderate 493 Minor

Ingredients driving the most interactions

Rhodiola rosea 1,271
Caffeine 655
Vitamin C 207
Acerola Concentrate Proprietary Blend 128
Spinach dehydrate 88

Individual Drug Interactions

The ingredients in XS Energy + Focus interact with 1,495 drugs. Click any drug to see the details.

5 of the 5 ingredients in XS Energy + Focus interact with drugs. Each result below shows which ingredient is responsible. Rhodiola rosea Caffeine Vitamin C Acerola Concentrate Proprietary Blend Spinach dehydrate

Each ingredient & the kinds of drugs it affects

For each ingredient in XS Energy + Focus 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.

Rhodiola rosea10 drug types · 1,271 drugs

Antidiabetes Drugs

Theoretically, taking rhodiola with antidiabetes drugs might increase the risk of hypoglycemia.
In vitro and animal research shows that rhodiola extract can decrease blood glucose due to alpha-glucosidase activity.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, taking rhodiola with antihypertensive drugs might increase the risk of hypotension.
In vitro and animal research shows that rhodiola extract inhibits angiotensin-converting enzyme (ACE) and might lower blood pressure.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, rhodiola might increase levels of drugs metabolized by CYP2C9.
In vitro research shows that rhodiola inhibits CYP2C9. This effect is highly variable and appears to be dependent on the rhodiola product studied. Also, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours.

Likelihood Possible Evidence B
Immunosuppressants

Theoretically, rhodiola use might interfere with immunosuppressive therapy.
In vitro and animal research show that rhodiola has immunostimulatory effects.

Likelihood Possible Evidence D
Losartan (Cozaar)

Rhodiola might increase the levels and adverse effects of losartan.
A clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours.

Likelihood Probable Evidence B
P-Glycoprotein Substrates

Theoretically, rhodiola might increase levels of P-glycoprotein substrates.
In vitro research shows that rhodiola inhibits P-glycoprotein. Theoretically, using rhodiola with P-glycoprotein substrates might increase drug levels and potentially increase the risk of adverse effects.

Likelihood Possible Evidence D
Antidepressant Drugs

Theoretically, rhodiola might increase the risk of adverse effects when taken with antidepressants.
A review of adverse event reports in Poland identified cases of tachyarrhythmias, myalgia, arthralgia, gum pain, restless leg syndrome, swallowing disorders, and changes in consciousness when rhodiola was taken in combination with paroxetine, escitalopram, fluoxetine, sertraline, trazodone, and/or duloxetine.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, rhodiola might increase the risk of adverse effects when taken with CNS depressants.
A review of adverse event reports in Poland identified cases of excessive sedation, myoclonus, hypotension, and hallucinations when rhodiola was taken with haloperidol, diazepam, or alprazolam.

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

Theoretically, rhodiola might increase levels of drugs metabolized by CYP1A2.
In vitro research shows that rhodiola inhibits CYP1A2. This effect is highly variable and appears to be dependent on the rhodiola product studied. However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of caffeine, a CYP1A2 substrate.

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

Theoretically, rhodiola might increase levels of drugs metabolized by CYP3A4.
In vitro research shows that rhodiola inhibits CYP3A4. This effect is highly variable and appears to be dependent on the rhodiola product studied. However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of midazolam, a CYP3A4 substrate.

Likelihood Possible Evidence B
Rhodiola rosea full monograph & interactions

Caffeine41 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 full monograph & all 41 interactions

Vitamin C13 drug types · 207 drugs

Alkylating Agents

Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Aluminum

Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption. In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely. Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.

Likelihood Probable Evidence B
Antitumor Antibiotics

Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Estrogens

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.

Likelihood Probable Evidence B
Fluphenazine (Prolixin)

Theoretically, vitamin C might decrease levels of fluphenazine.
In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started. The mechanism is not known, and there is no further data to confirm this interaction.

Likelihood Possible Evidence D
Indinavir (Crixivan)

Vitamin C can modestly reduce indinavir levels.
One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown.

Likelihood Probable Evidence B
Levothyroxine (Synthroid, Others)

Vitamin C can increase levothyroxine absorption.
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH.

Likelihood Probable Evidence B
Warfarin (Coumadin)

High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption. There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time. Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant. However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.

Likelihood Possible Evidence D
Acetaminophen (Tylenol, Others)

High-dose vitamin C might slightly prolong the clearance of acetaminophen.
A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases. This effect is not likely to be clinically significant.

Likelihood Probable Evidence B
Aspirin

Acidification of the urine by vitamin C might increase aspirin levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction is not clinically significant.

Likelihood Possible Evidence B
Choline Magnesium Trisalicylate (Trilisate)

Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Niacin

Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.

Likelihood Possible Evidence A
Salsalate (Disalcid)

Acidification of the urine by vitamin C might increase salsalate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Likelihood Possible Evidence B
Vitamin C full monograph & interactions

Acerola Concentrate Proprietary Blend6 drug types · 128 drugs

Alkylating Agents

Theoretically, the antioxidant effects of acerola might reduce the effectiveness of alkylating agents.
Acerola contains vitamin C, an antioxidant. There is concern that antioxidants might reduce the activity of chemotherapy drugs that generate free radicals, such as alkylating agents. In contrast, other researchers theorize that antioxidants might make alkylating chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Likelihood Possible Evidence D
Antitumor Antibiotics

Theoretically, the antioxidant effects of acerola might reduce the effectiveness of antitumor antibiotics.
Acerola contains vitamin C, an antioxidant. There is concern that antioxidants might reduce the activity of chemotherapy drugs that generate free radicals, such as antitumor antibiotics. In contrast, other researchers theorize that antioxidants might make antitumor antibiotic chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on antitumor antibiotic chemotherapy.

Likelihood Possible Evidence D
Aluminum

Theoretically, concomitant use of acerola with aluminum salts might increase the amount of aluminum absorbed.
Acerola contains vitamin C. It is thought that vitamin C chelates aluminum, keeping it in solution and available for absorption. In people with normal renal function, urinary excretion of aluminum likely increases, making aluminum retention and toxicity unlikely. However, patients with renal failure who take aluminum-containing compounds, such as phosphate binders, should avoid acerola in doses that provide more vitamin C than the recommended dietary allowances.

Likelihood Possible Evidence D
Aspirin

Theoretically, acerola might reduce the clearance of aspirin; however, its vitamin C content is likely too low to produce clinically significant effects.
Acerola contains vitamin C. It has been suggested that acidification of the urine by vitamin C can decrease the urinary excretion of salicylates, increasing plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion. The vitamin C content of acerola is typically about 2000 mg per 100 grams. Thus, a clinically significant interaction between acerola and aspirin is unlikely.

Likelihood Unlikely Evidence B
Estrogens

Theoretically, concomitant use of acerola with estrogens might increase estrogenic effects.
Acerola contains vitamin C. Increases in plasma estrogen levels of up to 55% have occurred under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. However, increases in plasma estrogen levels may occur when women who are deficient in vitamin C take supplements.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, acerola might reduce the effectiveness of warfarin; however, its vitamin C content is likely too low to produce clinically significant effects.
Acerola contains vitamin C. High doses of vitamin C may reduce the response to warfarin, possibly by causing diarrhea and reducing warfarin absorption. This occurred in two people who took up to 16 grams daily of vitamin C, and resulted in decreased prothrombin time. Lower doses of 5-10 grams daily of vitamin C can also reduce warfarin absorption, but this does not seem to be clinically significant. The vitamin C content of acerola is typically about 2000 mg per 100 grams. Thus, a clinically significant interaction between acerola and warfarin is unlikely.

Likelihood Unlikely Evidence D
Acerola Concentrate Proprietary Blend full monograph & interactions

Spinach dehydrate2 drug types · 88 drugs

Antidiabetes Drugs

There are claims that spinach leaves have hypoglycemic effects. Evidence from clinical research suggests that consumption of a spinach-rich meal reduces post-meal blood glucose levels. Theoretically, spinach might have additive effects with antidiabetes drugs and increase the risk of hypoglycemia. Monitor blood glucose levels closely. Dose adjustments might be necessary. Some antidiabetes drugs include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), and others.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Spinach contains vitamin K, which can interfere with the activity of warfarin.
In human research, although eating spinach with one meal does not result in coagulation test results outside the therapeutic range, daily consumption for one week necessitates dose adjustment of warfarin. Individuals using anticoagulants should consume a consistent daily amount of spinach to maintain the effect of anticoagulant therapy.

Likelihood Possible Evidence D
Spinach dehydrate full monograph & interactions
The maker

Brand information

Manufacturer and brand details for XS Energy + Focus, from the product label.

Nutrilite

See all Nutrilite products
Name
Amway Corp.
City
Ada
State
MI
ZipCode
49355
Phone Number
1-800-253-6500
Web Address
Amway.com/Nutrilite
Pharmacist Counseling Corner

XS Energy + Focus by Nutrilite: Common Questions

Does XS Energy + Focus by Nutrilite interact with any medications?
Yes. Based on its ingredients, XS Energy + Focus has a known interaction with 1,495 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?
XS Energy + Focus contains 5 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.
Is this safe if I'm on birth control or hormone therapy?
Not without checking first. The vitamin C in this product can increase blood levels of estrogens by up to 55%, which may intensify side effects or reduce effectiveness. Talk to your pharmacist or doctor about whether it's okay for you.
Can I take this if I'm on a blood thinner like warfarin?
No, not without medical approval. Both vitamin C and spinach in this product can interfere with warfarin's effectiveness. Spinach contains vitamin K, which directly counteracts the drug, and consistent daily use would require your warfarin dose to be adjusted. Check with your doctor first.
What's the energy boost from—is it just caffeine?
Caffeine is the main energy ingredient, and the product also contains rhodiola rosea, which is used traditionally to support focus and energy. Caffeine is proven effective for mental alertness and athletic performance.
Can I take this if I have diabetes?
Not without checking with your doctor. Rhodiola and spinach both have the potential to lower blood sugar, which could add to the effect of diabetes medications and increase your risk of low blood sugar (hypoglycemia).
Is this okay during pregnancy or breastfeeding?
It depends on the ingredient. Vitamin C at normal food and prenatal vitamin amounts is fine, but avoid high-dose supplements. Rhodiola and silicon dioxide safety data advises against them in pregnancy and breastfeeding. For acerola, caffeine, and spinach dehydrate, there isn't enough data on file—talk to your doctor or pharmacist for personalized advice.
What's silicon dioxide doing in an energy product?
Silicon is included for bone health support, though the evidence for its effectiveness is limited. It's also used as an inactive ingredient (anti-caking agent) in many supplements. The amount in food and most supplements is well tolerated.

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.

XS Energy + Focus label
Go deeper

The Full Monographs Behind XS Energy + Focus’s Ingredients

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

Herb & supplement monograph

Rhodiola

Interacts with 1,271 drugs

Rhodiola is an herb traditionally used to fight fatigue and help the body cope with stress. Some small studies suggest it may modestly reduce fatigue and improve mood, but the evidence is li...

Read the full Rhodiola monograph → Herb & supplement monograph

Vitamin C

Interacts with 207 drugs

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an...

Read the full Vitamin C monograph → Herb & supplement monograph

Acerola

Interacts with 128 drugs

Acerola is a small tropical fruit prized for its very high natural vitamin C content, and it is mostly used as a food-based source of vitamin C and antioxidants. While vitamin C itself has w...

Read the full Acerola monograph → Herb & supplement monograph

Silicon

Silicon is a trace mineral found in the body and in foods like oats, barley, and certain fruits and vegetables, and it is popular in supplements for hair, skin, nail, and bone health. Some s...

Read the full Silicon 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

Spinach

Interacts with 88 drugs

Spinach is a nutrient-dense leafy green that is a healthy part of a balanced diet, providing vitamins, minerals, fiber, and antioxidants. While it is very safe as a food, concentrated supple...

Read the full Spinach monograph →
Sources

Sources & How We Checked

XS Energy + Focus'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 345 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.

Silicon 19 references
  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  2. Jugdaohsingh R, Anderson SH, Tucker KL, et al. Dietary silicon intake and absorption. Am J Clin Nutr 2002;75:887-93. PubMed
  3. Ichiyanagi O, Sasagawa I, Adachi Y, et al. Silica urolithiasis without magnesium trisilicate intake. Urol Int 1998;61:39-42. PubMed
  4. Levison DA, Crocker PR, Banim S, Wallace DM. Silica stones in the urinary bladder. Lancet 1982;1:704-5. PubMed
  5. Lee MH, Lee YH, Hsu TH, et al. Silica stone--development due to long time oral trisilicate intake. Scand J Urol Nephrol 1993;27:267-9. PubMed
  6. Cruz Guerra, N. A., Gomez Garcia, M. A., Lovaco, Castellano F., Saez Garrido, J. C., Garcia, Cuerpo E., and Escudero, Barrilero A. [Silica urolithiasis: report of a new case]. Actas Urol.Esp 2000;24(2):202-204.
  7. Merget, R., Bauer, T., Kupper, H. U., Philippou, S., Bauer, H. D., Breitstadt, R., and Bruening, T. Health hazards due to the inhalation of amorphous silica. Arch Toxicol. 2002;75(11-12):625-634. PubMed
  8. Khuder, S. A., Peshimam, A. Z., and Agraharam, S. Environmental risk factors for rheumatoid arthritis. Rev Environ Health 2002;17(4):307-315. PubMed
  9. McLaughlin, J. K., Chow, W. H., and Levy, L. S. Amorphous silica: a review of health effects from inhalation exposure with particular reference to cancer. J Toxicol.Environ Health 4-25-1997;50(6):553-566. DOI
  10. Pelucchi, C., Pira, E., Piolatto, G., Coggiola, M., Carta, P., and La, Vecchia C. Occupational silica exposure and lung cancer risk: a review of epidemiological studies 1996-2005. Ann.Oncol. 2006;17(7):1039-1050. PubMed
  11. Gillissen, A., Gessner, C., Hammerschmidt, S., Hoheisel, G., and Wirtz, H. [Health significance of inhaled particles]. Dtsch.Med Wochenschr. 3-24-2006;131(12):639-644.
  12. Hu, J. F., Qu, H., and Wang, J. Z. [Meta analysis for relationship between exposure of free silicon dioxide and lung tumor]. Zhonghua Lao.Dong.Wei Sheng Zhi.Ye.Bing.Za Zhi. 2006;24(7):415-417.
  13. Jugdaohsingh, R. Silicon and bone health. J Nutr Health Aging 2007;11(2):99-110.
  14. Lacasse, Y., Martin, S., Gagne, D., and Lakhal, L. Dose-response meta-analysis of silica and lung cancer. Cancer Causes Control 2009;20(6):925-933. PubMed
  15. McCormic, Z. D., Khuder, S. S., Aryal, B. K., Ames, A. L., and Khuder, S. A. Occupational silica exposure as a risk factor for scleroderma: a meta-analysis. Int Arch Occup.Environ Health 2010;83(7):763-769. PubMed
  16. Haddad, F. S. and Kouyoumdjian, A. Silica stones in humans. Urol.Int 1986;41(1):70-76. PubMed
  17. Tervaert, J. W., Stegeman, C. A., and Kallenberg, C. G. Silicon exposure and vasculitis. Curr Opin.Rheumatol 1998;10(1):12-17. PubMed
  18. Steenland, K. and Stayner, L. Silica, asbestos, man-made mineral fibers, and cancer. Cancer Causes Control 1997;8(3):491-503. PubMed
  19. Boqué N, Valls RM, Pedret A, Puiggrós F, Arola L, Solà R. Relative absorption of silicon from different formulations of dietary supplements: a pilot randomized, double-blind, crossover post-prandial study. Sci Rep 2021;11(1):16479. PubMed

See these in context on the Silicon monograph →

Acerola 20 references
  1. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  2. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  3. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  4. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  5. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  6. Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
  7. Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
  8. Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
  9. Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
  10. Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601. PubMed
  11. Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
  12. Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
  13. Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31. PubMed
  14. Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed
  15. Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7. PubMed
  16. Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6. PubMed
  17. Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S. PubMed
  18. Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S. PubMed
  19. Denadai R, Souza FM, Valle MR. Fecal impaction by rectal acerola bezoar. Indian J Pediatr 2013;80(5):432-3. PubMed
  20. Raulf-Heimsoth M, Stark R, Sander I, et al. Anaphylactic reaction to apple juice containing acerola: cross-reactivity to latex due to prohevein. J Allergy Clin Immunol 2002;109(4):715-6. PubMed

See these in context on the Acerola monograph →

Rhodiola 13 references
  1. Kim SH, Hyun SH, Choung SY. Antioxidative effects of Cinnamomi cassiae and Rhodiola rosea extracts in liver of diabetic mice. Biofactors 2006;26:209-19.
  2. Kwon YI, Jang HD, Shetty K. Evaluation of Rhodiola crenulata and Rhodiola rosea for management of type II diabetes and hypertension. Asia Pac J Clin Nutr 2006;15:425-32.
  3. Bystritsky A, Kerwin L, Feusner JD. A pilot study of Rhodiola rosea (Rhodax) for generalized anxiety disorder (GAD). J Altern Complement Med 2008;14:175-80.
  4. Shevtsov VA, Zholus BI, Shervarly VI, et al. A randomized trial of two different doses of a SHR-5 Rhodiola rosea extract versus placebo and control of capacity for mental work. Phytomedicine 2003;10:95-105. PubMed
  5. Apostolidis E, Kwon YI, Shetty K. Potential of cranberry-based herbal synergies for diabetes and hypertension management. Asia Pac J Clin Nutr 2006;15:433-41.
  6. Hellum BH, Tosse A, Hoybakk K, et al. Potent in vitro inhibition of CYP3A4 and P-glycoprotein by Rhodiola rosea. Planta Med 2010;76:331-8.
  7. Skopriska-Rozewska E, Wojcik R, Siwicki AK, et al. The effect of Rhodiola quadrifida extracts on cellular immunity in mice and rats. Pol J Vet Sci 2008;11:105-11.
  8. Mishra KP, Chanda S, Shukla K, Ganju L. Adjuvant effect of aqueous extract of Rhodiola imbricate rhizome on the immune responses to tetanus toxoid and ovalbumin in rats. Immunopharmacol Immunotoxicol 2010;32:141-6.
  9. Li HX, Sze SC, Tong Y, Ng TB. Production of Th1- and Th2-dependent cytokines induced by the Chinese medicine herb, Rhodiola algida, on human peripheral blood monocytes. J Ethnopharmacol 2009;123:257-66. PubMed
  10. Mishra KP, Ganju L, Chanda S, et al. Aqueous extract of Rhodiola imbricate rhizome stimulates Toll-like receptor 4, granzyme-B and Th1 cytokines in vitro. Immunobiology 2009;214:27-31.
  11. Thu OK, Nilsen OG, Hellum B. In vitro inhibition of cytochrome P-450 activities and quantification of constituents in a selection of commercial Rhodiola rosea products. Pharm Bio. 2016 Dec;54(12):3249-3256.
  12. Thu OK, Spigset O, Nilsen OG, Hellum B. Effect of commercial Rhodiola rosea on CYP enzyme activity in humans. Eur J Clin Pharmacol. 2016 Mar;72(3):295-300. PubMed
  13. Woron J, Siwek M. Unwanted effects of psychotropic drug interactions with medicinal products and diet supplements containing plant extracts. Psychiatr Pol 2018;52(6):983-96. PubMed

See these in context on the Rhodiola monograph →

Vitamin C 51 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  3. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  4. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  5. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
  6. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
  7. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  8. Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
  9. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  10. Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
  11. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
  12. Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
  13. Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
  14. Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
  15. Traxer O, Huet B, Poindexter J, et al. Effect of ascorbic acid consumption on urinary stone risk factors. J Urol 2003;170:397-401.. PubMed
  16. Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
  17. Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601. PubMed
  18. Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
  19. Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
  20. Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31. PubMed
  21. Dysken MW, Cumming RJ, Channon RA, Davis JM. Drug interaction between ascorbic acid and fluphenazine. JAMA 1979;241:2008. DOI
  22. Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed
  23. Slain D, Amsden JR, Khakoo RA, et al. Effect of high-dose vitamin C on the steady-state pharmacokinetics of the protease inhibitor indinavir in healthy volunteers. Pharmacotherapy 2005;25:165-70. PubMed
  24. Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6. PubMed
  25. Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7. PubMed
  26. Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6. PubMed
  27. Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed
  28. Taylor EN, Stampfer MJ, Curhan GC. Dietary factors and the risk of incident kidney stones in men: new insights after 14 years of follow-up. J Am Soc Nephrol 2004;15:3225-32. PubMed
  29. Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed
  30. Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S. PubMed
  31. Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S. PubMed
  32. Fairweather-Tait S, Hickson K, McGaw B, et al. Orange juice enhances aluminium absorption from antacid preparation. Eur J Clin Nutr. 1994;48(1):71-3.
  33. Gruenwald, J., Graubaum, H. J., Busch, R., and Bentley, C. Safety and tolerance of ester-C compared with regular ascorbic acid. Adv.Ther. 2006;23(1):171-178.
  34. Rahimi, R., Nikfar, S., Rezaie, A., and Abdollahi, M. A meta-analysis on the efficacy and safety of combined vitamin C and E supplementation in preeclamptic women. Hypertens.Pregnancy. 2009;28(4):417-434. PubMed
  35. Einerson, B., Nathorn, C., Kitiyakara, C., Sirada, M., and Thamlikitkul, V. The efficacy of ascorbic acid in suboptimal responsive anemic hemodialysis patients receiving erythropoietin: a meta-analysis. J Med.Assoc.Thai. 2011;94 Suppl 1:S134-S146.
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See these in context on the Vitamin C monograph →

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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.

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