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Dietary supplement

Thyro Rx Ingredients & Drug Interactions

by HoltraCeuticals

Thyro Rx label
See full label image
Capsule 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 Thyro Rx 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

Thyro Rx is a dietary supplement by HoltraCeuticals with 6 active ingredients. Its ingredients are commonly taken for mental focus and alertness, coping with stress, fatigue and sleep loss.Based on those ingredients, 1,488 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Ashwagandha Extract, Coleus Forskohlii, Bladderwrack Extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Thyro Rx by HoltraCeuticals

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

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HelloPharmacist Scorecard of Thyro Rx by HoltraCeuticals

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

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 6 of its 6 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

Thyro Rx contains six ingredients. L-Tyrosine is an amino acid that serves as a building block for thyroid hormones.

Selenium is a mineral that plays a role in thyroid hormone metabolism and antioxidant defense. Ashwagandha Extract is an herbal supplement traditionally used for stress and sleep support.

Coleus Forskohlii is a plant extract studied for various effects. Guggul Extract comes from tree resin and has been used in traditional medicine.

We could not check Bladderwrack Extract for its interaction profile. The capsule also contains one inactive ingredient, microcrystalline cellulose, which is a binder.

Does it work?

Moderate 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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: Thyroid health support.
  • We looked for evidence on: Hypothyroidism, Hyperthyroidism, Autoimmune thyroiditis, Thyroid function, Metabolic support, Thyroid hormone balance.
  • The strongest evidence on file: Selenium is rated "Possibly Effective" for Autoimmune thyroiditis (Natural Medicines).
  • Also on file: Fucus Vesiculosus is rated "Insufficient Reliable Evidence To Rate" for Hypothyroidism.
  • Also on file: Ashwagandha is rated "Insufficient Reliable Evidence To Rate" for Hypothyroidism.

The evidence for what this product does is mixed and limited. L-Tyrosine is effective for PKU (phenylketonuria) and possibly effective for cognitive function and memory, but possibly ineffective for athletic performance and has insufficient evidence for alcohol use disorder and dementia.

Selenium is likely effective for selenium deficiency and possibly effective for Kashin-Beck disease, pre-eclampsia, and autoimmune thyroiditis, but possibly ineffective for dyslipidemia. Ashwagandha is possibly effective for insomnia, anxiety, stress, and generalized anxiety disorder, with insufficient evidence for bipolar disorder.

For Coleus Forskohlii and Guggul Extract, the evidence we hold is insufficient to rate their effectiveness for the conditions they're studied for — angina, asthma, cancer, congestive heart failure, eczema, dry eye, obesity, acne, hemorrhoids, and high cholesterol. We don't have effectiveness data on file for Bladderwrack Extract.

The evidence, ingredient by ingredient Tyrosine Selenium Ashwagandha Coleus Guggul Fucus Vesiculosus

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.

L-Tyrosine is generally well tolerated in healthy adults, though it's not well studied long-term; common side effects at higher doses include fatigue, headache, heartburn, and nausea. Safety data during pregnancy and breastfeeding are insufficient — talk with your doctor or pharmacist for personalized advice.

Selenium is generally well tolerated at recommended amounts, but excess can be toxic; common side effects include gastric upset, headache, and rash, while excessive amounts can cause hair loss, skin problems, fatigue, nail changes, nausea, vomiting, and weight loss. Ashwagandha is generally well tolerated short-term in healthy adults, though long-term safety data are limited; common side effects are diarrhea, upset stomach, nausea, and vomiting.

It's traditionally thought to risk miscarriage, so safety data advise against use during pregnancy; there isn't enough information for breastfeeding. Coleus is generally well tolerated but not well studied long-term; common side effects include constipation, diarrhea, nausea, and vomiting.

Safety data advise against use during pregnancy and breastfeeding. Guggul is generally well tolerated but may cause digestive upset and skin reactions; common side effects are belching, bloating, diarrhea, headache, nausea, taste changes, and rash.

Safety data advise against use during pregnancy because it may stimulate the uterus; there isn't enough information for breastfeeding. We don't have safety data on file for Bladderwrack Extract.

Side effects, ingredient by ingredient Tyrosine Selenium Ashwagandha Coleus Guggul Fucus Vesiculosus

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?
  • 6 of the 6 matched ingredients can interact with medications — Guggul, Fucus Vesiculosus, Ashwagandha, Selenium, Tyrosine, among others.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications; lithium; Parkinson's medications.
  • For scale: 1,489 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 taking Thyro Rx, double-check with your pharmacist or doctor if you take nitrates (like nitroglycerin) or calcium channel blockers — Coleus poses Major-severity risks. Check if you take blood pressure lowering drugs (Coleus, Ashwagandha, and L-Tyrosine all have additive effects), blood thinners or antiplatelet drugs (Selenium, Coleus, and Guggul all increase bleeding risk), thyroid hormone medication (L-Tyrosine, Ashwagandha, and Guggul can all increase its effects), diabetes medication (Ashwagandha may increase low blood sugar risk), sedatives or benzodiazepines (Ashwagandha may increase sedation), levodopa (L-Tyrosine may reduce its effectiveness), barbiturates (Selenium may prolong sedation), warfarin (Selenium and Coleus may interfere), immunosuppressants (Selenium and Ashwagandha may reduce effectiveness), propranolol or diltiazem (Guggul may reduce effectiveness), contraceptives or estrogen therapy (Guggul may increase estrogen effects), or tamoxifen (Guggul may interfere).

No interactions are documented in our data for Bladderwrack Extract, though we could not check it fully.

Check your own medication Run your meds through the checker above

The bottom line

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

Thyro Rx is a multi-ingredient supplement aimed at thyroid support, but the evidence for its active ingredients is sparse or mixed. If you take any blood pressure medication, heart drugs (especially nitrates or calcium channel blockers), blood thinners, diabetes medication, sedatives, thyroid hormone, or immunosuppressants, talk to your pharmacist or doctor before using this product — the interactions are real and could affect how your medications work.

Pregnant or breastfeeding? Check with your healthcare provider first.

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

Assessment coverage: 6 of 6 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Mar 25, 2013.

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 Thyro Rx, straight from the product label.

Brand HoltraCeuticals
Net contents 120 Capsule(s)
Market status On market
Date entered into DSLD Mar 25, 2013
DSLD ID 19398
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Dairy Free
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 Thyro Rx by HoltraCeuticals, 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:
4 Capsule(s)
Maximum serving Sizes:
4 Capsule(s)
Servings per container
30
IngredientAmount% DV
L-Tyrosine450 mg--
Selenium400 mcg571%
Ashwagandha Extract250 mg--
Coleus Forskohlii900 mg--
Guggul Extract300 mg--
Bladderwrack Extract200 mg--

Other ingredients: Micro Crystalline Cellulose

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.
Suggested/Recommended/Usage/Directions

Suggested Use: Take 4 capsules daily with meals. Can be taken throughout the day or as directed by a health professional.

Storage

Store in a cool, dry place with the lid tightly closed.

Precautions

Keep out of reach of children.

WARNING: Consult your physician prior to using this product if you are pregnant, nursing, taking medication or have a medical condition.

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.

Seals/Symbols

Freshly Made

General Statements

Made in a GMP Certified Facility in USA

Supports Healthy Thyroid Function

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

HOLTORF MEDICAL GROUP(R) CENTERS FOR HORMONE IMBALANCE, HYPOTHYROIDISM AND FATIGUE

Formulation

No artificial colors, no artificial flavors, no milk or milk derivatives, no preservatives, no sodium.

General

WO-0615-CPN-1

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

See for yourself

Thyro Rx by HoltraCeuticals label

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

Thyro Rx 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 Thyro Rx by HoltraCeuticals

These are the 6 active ingredients this product is made of. Select any to open its full monograph.

Serving size4 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.

L-Tyrosine

Interacts with
21 drugs
450 mg per serving

L-tyrosine is an amino acid your body uses to make brain chemicals like dopamine and norepinephrine. Some studies suggest it may help mental performan...

L-Tyrosine monograph & interactions

Selenium

Interacts with
321 drugs
400 mcg per serving Form: L-Selenomethionine

Selenium is an essential trace mineral your body needs in small amounts for thyroid function, antioxidant defense, and immune health. Most people who...

Selenium monograph & interactions

Ashwagandha Extract

Interacts with
1,372 drugs
250 mg per serving

Ashwagandha is an Ayurvedic herb most often taken to help with stress, anxiety, and sleep, and some small studies suggest it may help, though the evid...

Ashwagandha Extract monograph & interactions

Coleus Forskohlii

Interacts with
915 drugs
900 mg per serving

Coleus is a plant from the mint family whose root contains a compound called forskolin, often marketed for weight loss, asthma, and heart health. Whil...

Coleus Forskohlii monograph & interactions

Guggul Extract

Interacts with
757 drugs
300 mg per serving Form: Guggulsterones

Guggul is a gum resin from the Commiphora wightii tree, long used in Ayurvedic medicine for cholesterol, joint, and skin problems. Modern studies are...

Guggul Extract monograph & interactions

Bladderwrack Extract

Interacts with
891 drugs
200 mg per serving Form: Iodine

Fucus vesiculosus (bladderwrack) is a brown seaweed rich in iodine that has been used traditionally for thyroid concerns, weight, and skin. There is l...

Bladderwrack Extract monograph & interactions

Other (inactive) ingredients: Micro Crystalline Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

Thyro Rx by HoltraCeuticals Drug Interactions

Want to check YOUR meds against Thyro Rx?

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
1,488Drugs
29 Major 1,368 Moderate 91 Minor

Ingredients driving the most interactions

Ashwagandha Extract 1,372
Coleus Forskohlii 915
Bladderwrack Extract 891
Guggul Extract 757
Selenium 321

Individual Drug Interactions

The ingredients in Thyro Rx interact with 1,488 drugs. Click any drug to see the details.

6 of the 6 ingredients in Thyro Rx interact with drugs. Each result below shows which ingredient is responsible. Ashwagandha Extract Coleus Forskohlii Bladderwrack Extract Guggul Extract Selenium L-Tyrosine

Each ingredient & the kinds of drugs it affects

For each ingredient in Thyro Rx 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.

Ashwagandha Extract10 drug types · 1,372 drugs

Antidiabetes Drugs

Theoretically, taking ashwagandha with antidiabetes drugs might increase the risk of hypoglycemia.
There is preliminary clinical evidence suggesting that ashwagandha might lower blood glucose levels. Theoretically, ashwagandha might have additive effects when used with antidiabetes drugs and increase the risk of hypoglycemia.

Likelihood Possible Evidence B
Antihypertensive Drugs

Theoretically, taking ashwagandha with antihypertensive drugs might increase the risk of hypotension.
Animal research suggests that ashwagandha might lower systolic and diastolic blood pressure. Theoretically, ashwagandha might have additive effects when used with antihypertensive drugs and increase the risk of hypotension.

Likelihood Possible Evidence D
Benzodiazepines

Theoretically, taking ashwagandha might increase the sedative effects of benzodiazepines.
There is preliminary evidence that ashwagandha might have an additive effect with diazepam (Valium) and clonazepam (Klonopin). This may also occur with other benzodiazepines.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, taking ashwagandha might increase the sedative effects of CNS depressants.
Ashwagandha seems to have sedative effects. Theoretically, this may potentiate the effects of barbiturates, other sedatives, and anxiolytics.

Likelihood Possible Evidence D
Hepatotoxic Drugs

Theoretically, taking ashwagandha with hepatotoxic drugs might increase the risk of liver damage.
Ashwagandha has been linked to cases of acute hepatitis, liver failure, hepatic encephalopathy, autoimmune hepatitis, the need for liver transplantation, and death due to liver failure.

Likelihood Possible Evidence D
Immunosuppressants

Theoretically, taking ashwagandha might decrease the effects of immunosuppressants.
Ashwagandha has demonstrated immunostimulant effects in humans. Animal research has shown that ashwagandha can attenuate the immunosuppression caused by cyclophosphamide.

Likelihood Possible Evidence D
Thyroid Hormone

Ashwagandha might increase the effects and adverse effects of thyroid hormone.
Concomitant use of ashwagandha with thyroid hormones may cause additive therapeutic and adverse effects. Preliminary clinical research and animal studies suggest that ashwagandha boosts thyroid hormone synthesis and secretion. In one clinical study, ashwagandha increased triiodothyronine (T3) and thyroxine (T4) levels by 41.5% and 19.6%, respectively, and reduced serum TSH levels by 17.4% from baseline in adults with subclinical hypothyroidism.

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

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that ashwagandha extract induces CYP1A2 enzymes.

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

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that ashwagandha extract induces CYP3A4 enzymes.

Likelihood Possible Evidence D
Serotonergic Drugs

Some animal studies have reported that ashwagandha can enhance serotonergic transmission by altering certain serotonin (5-HT) receptors. However, there is no evidence to suggest that ashwagandha increases the risk of serotonin-related effects, and there have been no published case reports of serotonin syndrome when combined with other serotonergic drugs. Nevertheless, due to the lack of extensive studies on the matter and the fact that ashwagandha appears to affect serotonergic pathways, it would be prudent to exercise caution when combining it with drugs that affect serotonin. [References: - Effects of Withania somnifera (Ashwaga ndha) on Stress and the Stress-Related Neuropsychiatric Disorders Anxiety, Depression, and Insomnia. Curr Neuropharmacol. 2021 Sep 14; 19: 1468–1495. - A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573577/]

Likelihood Possible Evidence C
Ashwagandha Extract full monograph & interactions

Coleus Forskohlii7 drug types · 915 drugs

Calcium Channel Blockers

Theoretically, combining coleus with calcium channel blockers might increase the coronary vasodilatory effects.
Forskolin, a constituent of coleus, and calcium channel blockers both cause coronary vasodilatory effects.

Likelihood Probable Evidence B
Nitrates

Theoretically, combining coleus with nitrates might increase the coronary vasodilatory effects.
Forskolin, a constituent of coleus, and nitrates both cause coronary vasodilatory effects.

Likelihood Probable Evidence B
Anticoagulant/Antiplatelet Drugs

Theoretically, concomitant use of coleus and anticoagulant or antiplatelet drugs might increase the risk of bruising and bleeding.
In vitro and animal research shows that forskolin, a constituent of coleus, can inhibit platelet aggregation and adhesion.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, combining coleus with antihypertensive drugs might cause additive blood pressure lowering effects and increase the risk of hypotension.
Animal research shows that forskolin, a constituent of coleus, may lower blood pressure.

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

Theoretically, taking coleus may affect drugs metabolized by CYP2C9 and increase the risk of adverse effects or reduce the effectiveness.
Research on the effect of coleus on CYP2C9 is conflicting. Some animal research shows that coleus extract can induce CYP2C9, while in vitro research shows that coleus can inhibit CYP2C9. Until more is known, advise patients that taking coleus might increase or decrease levels of drugs metabolized by CYP2C9.

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

Theoretically, taking coleus might decrease serum levels of drugs metabolized by CYP3A4.
In vitro research shows that coleus can activate the nuclear receptor, pregnane X receptor (PXR), which results in increased expression of CYP3A4. Although the clinical significance of this is not known, use caution when considering concomitant use of coleus and other drugs affected by these enzymes.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, taking coleus may affect the metabolism of warfarin and increase the risk of adverse effects or reduce the effectiveness.
Some animal research shows that coleus extract can induce cytochrome P450 2C9 (CYP2C9), an enzyme that metabolizes warfarin. However, other in vitro research shows that coleus can inhibit CYP2C9. Theoretically, taking coleus with drugs metabolized by CYP2C9 might affect drug levels and the risk of adverse effects. Until more is known, advise patients that taking coleus might increase or decrease levels of warfarin.

Likelihood Possible Evidence D
Coleus Forskohlii full monograph & interactions

Bladderwrack Extract9 drug types · 891 drugs

Amiodarone (Cordarone)

Theoretically, combining Fucus vesiculosus with amiodarone might cause excessively high iodine levels.
Fucus vesiculosus contains high concentrations of iodine. Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use might increase the risk of having excessive iodine levels and adversely affecting thyroid function. Monitor thyroid function.

Likelihood Probable Evidence D
Antithyroid Drugs

Due to its iodine content, Fucus vesiculosus might alter the effects of antithyroid drugs.
Fucus vesiculosus contains high concentrations of iodine. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Fucus vesiculosus while using antithyroid drugs could alter the effects of the antithyroid drugs.

Likelihood Possible Evidence D
Lithium

Concomitant use of Fucus vesiculosus and lithium has resulted in hyperthyroidism.
There is a case of hyperthyroidism occurring in a patient taking Fucus vesiculosus and lithium. Monitor thyroid hormones closely in patients taking lithium and Fucus vesiculosus concomitantly.

Likelihood Possible Evidence D
Thyroid Hormone

Due to its iodine content, Fucus vesiculosus might alter the effects of thyroid hormone.
Fucus vesiculosus contains high concentrations of iodine. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Fucus vesiculosus while using thyroid hormone could alter the effects of thyroid hormone.

Likelihood Possible Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, taking Fucus vesiculosus with antiplatelet or anticoagulant drugs might increase the risk of bruising and bleeding.
In vitro evidence suggests that a constituent of Fucus vesiculosus, known as fucoidan, has anticoagulant effects. However, in clinical research, fucoidan does not seem to have significant anticoagulant activity when taken orally, possibly due to poor absorption.

Likelihood Unlikely Evidence D
Cytochrome P450 2C8 (Cyp2C8) Substrates

Theoretically, concomitant use of Fucus vesiculosus with CYP2C8 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C8. This interaction has not been reported in humans.

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

Theoretically, concomitant use of Fucus vesiculosus with CYP2C9 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C9. This interaction has not been reported in humans.

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

Theoretically, concomitant use of Fucus vesiculosus with CYP2D6 substrates might alter the effects of these substrates.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, both inhibits and induces CYP2D6. This interaction has not been reported in humans.

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

Theoretically, concomitant use of Fucus vesiculosus with CYP3A4 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP3A4. This interaction has not been reported in humans.

Likelihood Possible Evidence D
Bladderwrack Extract full monograph & interactions

Guggul Extract9 drug types · 757 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, guggul might increase the risk of bleeding when taken with anticoagulant/antiplatelet drugs.
In vitro research and preliminary clinical studies suggest that guggul might have antiplatelet and anticoagulant effects.

Likelihood Possible Evidence B
Contraceptive Drugs

Theoretically, guggul might increase the risk of adverse effects when taken with contraceptive drugs.
In vitro research shows that guggul has estrogen-alpha receptor agonist activity.

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

Theoretically, guggul might reduce the effects of CYP3A4 substrates.
In vitro research shows that guggul constituents known as guggulsterones can induce CYP3A4.

Likelihood Probable Evidence D
Diltiazem (Cardizem, Others)

Guggul might reduce the effects of diltiazem.
A small pharmacokinetic study shows that concomitant use of guggul with diltiazem reduces the bioavailability of diltiazem.

Likelihood Probable Evidence B
Estrogens

Theoretically, guggul might increase the risk of adverse effects when taken with estrogens.
In vitro research shows that guggul constituents known as guggulsterones have estrogen-alpha receptor agonist activity.

Likelihood Possible Evidence D
Propranolol (Inderal)

Guggul might reduce the effects of propranolol.
A small pharmacokinetic study shows that concomitant use of guggul with propranolol reduces the bioavailability of propranolol.

Likelihood Probable Evidence B
Rosuvastatin (Crestor)

Theoretically, guggul might increase the effects and adverse effects of rosuvastatin.
Animal research shows that guggul increases the bioavailability and hypolipidemic effects of rosuvastatin. The mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Tamoxifen (Nolvadex)

Theoretically, guggul might interfere with tamoxifen therapy.
In vitro research shows that guggul has estrogen-alpha receptor agonist activity.

Likelihood Possible Evidence D
Thyroid Hormone

Theoretically, guggul might increase the risk for adverse effects when taken with thyroid hormone therapy.
Animal research suggests that guggul has thyroid-stimulating effects.

Likelihood Probable Evidence B
Guggul Extract full monograph & interactions

Selenium6 drug types · 321 drugs

Anticoagulant/Antiplatelet Drugs

Selenium may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Clinical research suggests that taking selenium 10 mcg/kg/day can increase bleeding times by increasing prostacyclin production, which inhibits platelet activity. Other clinical research suggests that taking selenium 75 mcg daily, in combination with ascorbic acid 600 mg, alpha-tocopherol 300 mg, and beta-carotene 27 mg, reduces platelet aggregation.

Likelihood Possible Evidence D
Barbiturates

Theoretically, selenium might prolong the sedating effects of barbiturates.
Laboratory research suggests that selenium can inhibit the hepatic metabolism of barbiturates. Selenium seems to prolong the sedative effect of pentobarbital in animal models.

Likelihood Possible Evidence D
Immunosuppressants

Theoretically, selenium supplementation may reduce the effectiveness of immunosuppressant therapy.
In vitro research and preliminary clinical evidence suggests that selenium may stimulate the immune system.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, selenium might interfere with warfarin activity.
Animal research suggests that selenium can increase warfarin activity. Selenium might interact with warfarin by displacing it from albumin binding sites, reducing its metabolism in the liver, or by decreasing production of vitamin K-dependent clotting factors. Selenium can also prolong bleeding times in humans by increasing prostacyclin production, which inhibits platelet activity.

Likelihood Possible Evidence D
Contraceptive Drugs

Contraceptive drugs might increase levels of selenium, although the clinical significance of this effect is unclear.
Some research suggests that oral contraceptives increase serum selenium levels in women taking oral contraceptives; however, other research shows no change in selenium levels. It is suggested that an increase could be due to increased carrier proteins, indicating a redistribution of selenium rather than a change in total body selenium.

Likelihood Possible Evidence B
Niacin

Selenium might reduce the beneficial effects of niacin on high-density lipoprotein (HDL) 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 selenium, or to the combination. It also is not known whether it will occur in other patient populations.

Likelihood Possible Evidence A
Selenium full monograph & interactions

L-Tyrosine2 drug types · 21 drugs

Levodopa

Theoretically, tyrosine might decrease the effectiveness of levodopa.
Tyrosine and levodopa compete for absorption in the proximal duodenum by the large neutral amino acid (LNAA) transport system. Advise patients to separate doses of tyrosine and levodopa by at least 2 hours.

Likelihood Probable Evidence D
Thyroid Hormone

Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Tyrosine is a precursor to thyroxine and might increase levels of thyroid hormones.

Likelihood Probable Evidence D
L-Tyrosine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Thyro Rx, from the product label.

HoltraCeuticals

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Web Address
Holtraceuticals.com
Pharmacist Counseling Corner

Thyro Rx by HoltraCeuticals: Common Questions

Does Thyro Rx by HoltraCeuticals interact with any medications?
Yes. Based on its ingredients, Thyro Rx has a known interaction with 1,488 medications, including 29 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Thyro Rx contains 6 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?
Ashwagandha and Guggul safety data advise against pregnancy use — Ashwagandha is traditionally thought to risk miscarriage, and Guggul may stimulate the uterus. L-Tyrosine, Selenium, and Coleus don't have enough safety data for pregnancy or breastfeeding. Talk with your doctor or pharmacist for personalized advice, especially if you're already on thyroid medication.
What does L-Tyrosine actually do?
L-Tyrosine is an amino acid your body uses to make thyroid hormones and other brain chemicals. It's effective for PKU (a rare genetic condition) and possibly effective for memory and thinking, but the evidence for other uses in this product is less clear.
Is selenium in this product safe?
Selenium at recommended doses is generally well tolerated. The key word is 'recommended' — excess selenium can be toxic and cause hair loss, skin rashes, and in extreme cases, organ damage. Don't take additional selenium supplements alongside this product unless your doctor advises it.
Can Ashwagandha make me drowsy?
Yes, drowsiness has been reported with ashwagandha use. If you take sedatives, benzodiazepines, or other sleep medications, ashwagandha may add to that effect — talk to your pharmacist before combining them.
Does Coleus lower blood pressure?
Yes, animal research suggests the main active compound in Coleus (forskolin) can lower blood pressure. If you already take blood pressure medication, combining this product with it could lower your pressure too much. Check with your pharmacist first.
What's in the capsule itself?
The capsule contains the six active ingredients plus one inactive ingredient — microcrystalline cellulose, which is a binder. There are no other fillers listed.

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.

Thyro Rx label
Go deeper

The Full Monographs Behind Thyro Rx’s Ingredients

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

Herb & supplement monograph

Tyrosine

Interacts with 21 drugs

L-tyrosine is an amino acid your body uses to make brain chemicals like dopamine and norepinephrine. Some studies suggest it may help mental performance during short-term stress, sleep loss,...

Read the full Tyrosine monograph → Herb & supplement monograph

Selenium

Interacts with 321 drugs

Selenium is an essential trace mineral your body needs in small amounts for thyroid function, antioxidant defense, and immune health. Most people who eat a varied diet get enough, and supple...

Read the full Selenium monograph → Herb & supplement monograph

Ashwagandha

Interacts with 1,372 drugs

Ashwagandha is an Ayurvedic herb most often taken to help with stress, anxiety, and sleep, and some small studies suggest it may help, though the evidence is still limited. It is generally w...

Read the full Ashwagandha monograph → Herb & supplement monograph

Coleus

Interacts with 915 drugs

Coleus is a plant from the mint family whose root contains a compound called forskolin, often marketed for weight loss, asthma, and heart health. While early lab and small human studies are...

Read the full Coleus monograph → Herb & supplement monograph

Guggul

Interacts with 757 drugs

Guggul is a gum resin from the Commiphora wightii tree, long used in Ayurvedic medicine for cholesterol, joint, and skin problems. Modern studies are mixed and often low-quality, and it can...

Read the full Guggul monograph → Herb & supplement monograph

Fucus Vesiculosus

Interacts with 891 drugs

Fucus vesiculosus (bladderwrack) is a brown seaweed rich in iodine that has been used traditionally for thyroid concerns, weight, and skin. There is little solid human evidence to support mo...

Read the full Fucus Vesiculosus monograph →
Sources

Sources & How We Checked

Thyro Rx'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 124 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.

Tyrosine 4 references
  1. Meyer JS, Welch KM, Deshmukh VD, et al. Neurotransmitter precursor amino acids in the treatment of multi-infarct dementia and Alzheimer's disease. J Amer Geriat Soc 1977;25:289-98.
  2. DiPiro JT, Talbert RL, Yee GC, et al; eds. Pharmacotherapy: A pathophysiologic approach. 4th ed. Stamford, CT: Appleton & Lange, 1999.
  3. Wood DR, Reimherr FW, Wender PH. Amino acid precursors for the treatment of attention deficit disorder, residual type. Psychopharmacol Bull 1985;21:146-9.
  4. van Spronsen FJ, van Rijn M, Bekhof J. Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets. Am J Clin Nutr 2001;73:153-7. PubMed

See these in context on the Tyrosine monograph →

Selenium 36 references
  1. 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/.
  2. 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
  3. Trafikowska U, Zachara BA, Wiacek M, et al. Selenium supply and glutathione peroxidase activity in breastfed Polish infants. Acta Paediatr 1996;85:1143-5. PubMed
  4. Duffield-Lillico AJ, Slate EH, Reid ME, et al. Selenium supplementation and secondary prevention of nonmelanoma skin cancer in a randomized trial. J Natl Cancer Inst 2003;95:1477-81.. PubMed
  5. 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
  6. Schiavon R, Freeman GE, Guidi GC, et al. Selenium enhances prostacyclin production by cultured endothelial cells: possible explanation for increased bleeding times in volunteers taking selenium as a dietary supplement. Thromb Res 1984;34:389-96. PubMed
  7. Davila JC, Edds GT, Osuna O, Simpson CF. Modification of the effects of aflatoxin B1 and warfarin in young pigs given selenium. Am J Vet Res 1983;44:1877-83. DOI
  8. Heese HD, Lawrence MA, Dempster WS, Pocock F. Reference concentrations of serum selenium and manganese in healthy nulliparas. S Afr Med J 1988;73:163-5.
  9. Lloyd B, Lloyd RS, Clayton BE. Effect of smoking, alcohol and other factors on the selenium status of a healthy population. J Epidemiol Commun Health 1983;37:213-7. PubMed
  10. Capel ID, Jenner M, Williams DC, et al. The effect of prolonged oral contraceptive steroid use on erythrocyte glutathione peroxidase activity. J Steroid Biochem 1981;14:729-32. PubMed
  11. Contempre B, Dumont JE, Ngo B, et al. Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium. J Clin Endocrinol PubMed
  12. Hofbauer LC, Spitzweg C, Magerstadt RA, Heufelder AE. Selenium-induced thyroid dysfunction. Postgrad Med J 1997;73:103-4. PubMed
  13. Debski B, Milner JA. Dietary selenium supplementation prolongs pentobarbital induced hypnosis. J Nutr Biochem 2004;15:548-53. PubMed
  14. Ishikawa M, Sasaki M, Koiwai K, et al. Inhibition of hepatic mixed-function oxidase enzymes in mice by acute and chronic treatment with selenium. J Pharmacobiodyn 1992;15:377-85. PubMed
  15. Lippmann SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the selenium and vitamin E cancer prevention trial (SELECT). JAMA 2009;301:39-51. DOI
  16. Reid SM, Middleton P, Cossich MC, Crowther CA. Interventions for clinical and subclinical hypothyroidism in pregnancy. Cochrane Database Syst Rev 2010;(7):CD007752. PubMed
  17. Vinceti, M., Wei, E. T., Malagoli, C., Bergomi, M., and Vivoli, G. Adverse health effects of selenium in humans. Rev.Environ.Health 2001;16(4):233-251. PubMed
  18. Abrams, C. K., Siram, S. M., Galsim, C., Johnson-Hamilton, H., Munford, F. L., and Mezghebe, H. Selenium deficiency in long-term total parenteral nutrition. Nutr Clin Pract 1992;7(4):175-178. PubMed
  19. Spiller, H. A. and Pfiefer, E. Two fatal cases of selenium toxicity. Forensic Sci Int 8-24-2007;171(1):67-72. PubMed
  20. Negro, R., Greco, G., Mangieri, T., Pezzarossa, A., Dazzi, D., and Hassan, H. The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies. J Clin Endocrinol.Metab 2007;92(4):1263-1268. PubMed
  21. Alexander, J. Selenium. Novartis.Found.Symp 2007;282:143-149.
  22. Salonen, J. T., Salonen, R., Seppanen, K., Rinta-Kiikka, S., Kuukka, M., Korpela, H., Alfthan, G., Kantola, M., and Schalch, W. Effects of antioxidant supplementation on platelet function: a randomized pair-matched, placebo-controlled, double-blind trial
  23. Kupka, R., Mugusi, F., Aboud, S., Msamanga, G. I., Finkelstein, J. L., Spiegelman, D., and Fawzi, W. W. Randomized, double-blind, placebo-controlled trial of selenium supplements among HIV-infected pregnant women in Tanzania: effects on maternal and chil
  24. Kamble, P., Mohsin, N., Jha, A., Date, A., Upadhaya, A., Mohammad, E., Khalil, M., Pakkyara, A., and Budruddin, M. Selenium intoxication with selenite broth resulting in acute renal failure and severe gastritis. Saudi.J Kidney Dis.Transpl. 2009;20(1):106
  25. Peretz, A., Neve, J., Desmedt, J., Duchateau, J., Dramaix, M., and Famaey, J. P. Lymphocyte response is enhanced by supplementation of elderly subjects with selenium-enriched yeast. Am.J Clin.Nutr. 1991;53(5):1323-1328. PubMed
  26. Kumpulainen, J., Salmenpera, L., Siimes, M. A., Koivistoinen, P., and Perheentupa, J. Selenium status of exclusively breast-fed infants as influenced by maternal organic or inorganic selenium supplementation. Am.J Clin.Nutr. 1985;42(5):829-835. PubMed
  27. Han, L. and Zhou, S. M. Selenium supplement in the prevention of pregnancy induced hypertension. Chin Med J (Engl) 1994;107(11):870-871.
  28. Kiremidjian-Schumacher, L., Roy, M., Wishe, H. I., Cohen, M. W., and Stotzky, G. Supplementation with selenium and human immune cell functions. II. Effect on cytotoxic lymphocytes and natural killer cells. Biol.Trace Elem.Res. 1994;41(1-2):115-127. PubMed
  29. Srivastava, A. K., Gupta, B. N., Bihari, V., and Gaur, J. S. Generalized hair loss and selenium exposure. Vet.Hum.Toxicol. 1995;37(5):468-469.
  30. Sudfeld CR, Aboud S, Kupka R, et al. Effect of selenium supplementation on HIV-1 RNA detection in breast milk of Tanzanian women. Nutrition 2014;30(9):1081-4. PubMed
  31. Rees K, Hartley L, Day C, et al. Selenium supplementation for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev 2013;1:CD009671. PubMed
  32. Thompson PA, Ashbeck EL, Roe DJ, et al. Selenium Supplementation for Prevention of Colorectal Adenomas and Risk of Associated Type 2 Diabetes. J Natl Cancer Inst. 2016;108(12). PubMed
  33. Wichman J, Winther KH, Bonnema SJ, Hegedüs L. Selenium supplementation significantly reduces thyroid autoantibody levels in patients with chronic autoimmune thyroiditis: a systematic review and meta-analysis. Thyroid 2016;26(12):1681-92. PubMed
  34. Vinceti M, Filippini T, Rothman KJ. Selenium exposure and the risk of type 2 diabetes: a systematic review and meta-analysis. Eur J Epidemiol. 2018 Sep;33(9):789-810. Epub 2018 Jul 5. Review. PubMed
  35. Fallah S, Sani FV, Firoozrai M. Effect of contraceptive pill on the selenium and zinc status of healthy subjects. Contraception. 2009;80(1):40-3. PubMed
  36. Malpas CB, Vivash L, Genc S, et al. A Phase IIa Randomized Control Trial of VEL015 (Sodium Selenate) in Mild-Moderate Alzheimer's Disease. J Alzheimers Dis. 2016;54(1):223-232. PubMed

See these in context on the Selenium monograph →

Ashwagandha 32 references
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Upton R, ed. Ashwagandha Root (Withania somnifera): Analytical, quality control, and therapuetic monograph. Santa Cruz, CA: American Herbal Pharmacopoeia 2000:1-25.
  3. Davis L, Kuttan G. Effect of Withania somnifera on cyclophosphamide-induced urotoxicity. Cancer Lett 2000;148:9-17. PubMed
  4. Davis L, Kuttan G. Suppressive effect of cyclophosphamide-induced toxicity by Withania somnifera extract in mice. J Ethnopharmacol 1998;62:209-14. PubMed
  5. Mishra LC, Singh BB, Dagenais S. Scientific basis for the therapeutic use of Withania somnifera (ashwagandha): a review. Altern Med Rev 2000;5:334-46. DOI
  6. Andallu B, Radhika B. Hypoglycemic, diuretic and hypocholesterolemic effect of winter cherry (Withania somnifera, Dunal) root. Indian J Exp Biol 2000;38:607-9.
  7. Kulkarni RR, Patki PS, Jog VP, et al. Treatment of osteoarthritis with a herbomineral formulation: a double-blind, placebo-controlled, cross-over study. J Ethnopharmacol 1991;33:91-5. PubMed
  8. Ahumada F, Aspee F, Wikman G, Hancke J. Withania somnifera exract. Its effects on arterial blood pressure in anaesthetized dogs. Phytother Res 1991;5:111-14.
  9. Panda S, Kar A. Withania somnifera and Bauhinia purpurea in the regulation of circulating thyroid hormone concentrations in female mice. J Ethnopharmacol 1999;67:233-39. PubMed
  10. Panda S, Kar A. Changes in thyroid hormone concentrations after administration of ashwagandha root extract to adult male mice. J Pharm Pharmacol 1998;50:1065-68. PubMed
  11. Sehgal, V. N., Verma, P., and Bhattacharya, S. N. Fixed-drug eruption caused by ashwagandha (Withania somnifera): a widely used Ayurvedic drug. Skinmed. 2012;10(1):48-49.
  12. Agnihotri AP, Sontakke SD, Thawani VR, Saoji A, Goswami VS. Effects of Withania somnifera in patients of schizophrenia: a randomized, double blind, placebo controlled pilot trial study. Indian J Pharmacol. 2013;45(4):417-8. PubMed
  13. Biswal BM, Sulaiman SA, Ismail HC, Zakaria H, Musa KI. Effect of Withania somnifera (Ashwagandha) on the development of chemotherapy-induced fatigue and quality of life in breast cancer patients. Integr Cancer Ther. 2013;12(4):312-22.
  14. Sharma AK, Basu I, Singh S. Efficacy and safety of Ashwagandha root extract in subclinical hypothyroid patients: a double-blind, randomized placebo-controlled trial. J Altern Complement Med. 2018 Mar;24(3):243-248. PubMed
  15. Durg S, Bavage S, Shivaram SB. Withania somnifera (Indian ginseng) in diabetes mellitus: A systematic review and meta-analysis of scientific evidence from experimental research to clinical application. Phytother Res. 2020;34(5):1041-1059.
  16. Björnsson HK, Björnsson ES, Avula B, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829. PubMed
  17. Tharakan A, Shukla H, Benny IR, Tharakan M, George L, Koshy S. Immunomodulatory Effect of Withania somnifera (Ashwagandha) Extract-A Randomized, Double-Blind, Placebo Controlled Trial with an Open Label Extension on Healthy Participants. J Clin Med 2021;1 PubMed
  18. Ireland PJ, Hardy T, Burt AD, Donnelly MC. Drug-induced hepatocellular injury due to herbal supplement ashwagandha. J R Coll Physicians Edinb. 2021;51(4):363-365. PubMed
  19. Kamal HI, Patel K, Brdak A, Heffernan J, Ahmad N. Ashwagandha as a unique cause of thyrotoxicosis presenting with supraventricular tachycardia. Cureus. 2022 Mar 25;14(3):e23494. PubMed
  20. Suryawanshi G, Abdallah M, Thomson M, Desai N, Chauhan A, Lim N. Ashwagandha-Associated Acute Liver Failure Requiring Liver Transplantation. Am J Ther 2023;30(1):e80-e83. PubMed
  21. Pusec CM, Wolsky R, Llerena C, Sura P. A Case of Supplement-Induced Hepatitis. Cureus 2022;14(10):e30433. PubMed
  22. Ajgaonkar A, Jain M, Debnath K. Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract for Improvement of Sexual Health in Healthy Women: A Prospective, Randomized, Placebo-Controlled Study. Cureus 2022;14(10):e30787. PubMed
  23. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed
  24. Lubarska M, Halasinski P, Hryhorowicz S, et al. Liver Dangers of Herbal Products: A Case Report of Ashwagandha-Induced Liver Injury. Int J Environ Res Public Health 2023;20(5):3921. PubMed
  25. Tóth M, Benedek AE, Longerich T, Seitz HK. Ashwagandha-induced acute liver injury: A case report. Clin Case Rep 2023;11(3):e7078.
  26. Bokan G, Glamocanin T, Mavija Z, et al. Herb-Induced Liver Injury by Ayurvedic Ashwagandha as Assessed for Causality by the Updated RUCAM: An Emerging Cause. Pharmaceuticals (Basel) 2023;16(8):1129. PubMed
  27. Patel PA, Sanborn E, Then R, Williams DM. Recurrent Reversible Cerebral Vasoconstriction Syndrome: A Report of Two Cases. Cureus 2023;15(8):e42992. PubMed
  28. Majeed M, Nagabhushanam K, Murali A, Vishwanathan DT, Mamidala RV, Mundkur L. A Standardized Withania somniferra (Linn.) Root Extract with Piperine Alleviates the Symptoms of Anxiety and Depression by Increasing Serotonin Levels: A Double-Blind, Randomize
  29. Philips CA, Valsan A, Theruvath AH, et al. Ashwagandha-induced liver injury-A case series from India and literature review. Hepatol Commun 2023;7(10):e0270. PubMed
  30. Hayashi M, Hamada H, Azuma SI, Hayashi K. Painless Thyroiditis by Withania somnifera (Ashwagandha). Cureus 2024;16(3):e55352. PubMed
  31. Vazirani S, Kothari A, Fujimoto J, Gomez M. Supplements Are Not a Synonym for Safe: Suspected Liver Injury From Ashwagandha. Fed Pract 2023;40(9):315-319. PubMed
  32. Patel M, Newell R, Hillier M, Ramalingam R. Herbal remedies as a potential cause of hypoadrenalism. Br J Hosp Med (Lond) 2024;85(6):1-4. PubMed

See these in context on the Ashwagandha monograph →

Coleus 16 references
  1. Baumann G, Felix S, Sattelberger U, Klein G. Cardiovascular effects of forskolin (HL-362) in patients with idiopathic congestiv cardiomyopathy. A comparative study with dobutamine and sodium nitroprusside. J Cardiovasc Pharmacol 1990;16:93-100.
  2. Kramer W, Thormann J, Kindler M, Schlepper M. Effects of forskolin on left ventricular function in dilated cardiomyopathy. Arzneimittelforschung 1987;37:364-7.
  3. Bauer K, Dietersdorfer F, Kaspar S, et al. Pharmacodynamic effects of inhaled dry powder formulations of fenoterol and colforsin in asthma. Clin Pharmacol Ther 1993;53:76-83. PubMed
  4. Christenson JT, Thulesius O, Nazzal MM. The effect of forskolin on blood flow, platelet metabolism, aggregation and ATP release. Vasa 1995;24:56-61.
  5. Agarwal KC, Zielinski BA, Maitra RS. Significance of plasma adenosine in the antiplatelet activity of forskolin: potentiation by dipyridamole and dilazep. Thromb Haemost 1989;61:106-10. DOI
  6. Agarwal KC, Parks RE. Forskolin: a potential antimetastatic agent. Int J Cancer 1983;32:801-4. PubMed
  7. Almeida, F. C. and Lemonica, I. P. The toxic effects of Coleus barbatus B. on the different periods of pregnancy in rats. J Ethnopharmacol 2000;73(1-2):53-60. PubMed
  8. Ding, X. and Staudinger, J. L. Induction of drug metabolism by forskolin: the role of the pregnane X receptor and the protein kinase a signal transduction pathway. J Pharmacol Exp Ther 2005;312(2):849-856. PubMed
  9. Staudinger, J. L., Ding, X., and Lichti, K. Pregnane X receptor and natural products: beyond drug-drug interactions. Expert.Opin Drug Metab Toxicol 2006;2(6):847-857. PubMed
  10. van Hecke, E., Hindryckx, P., Geuns, J. M., and Devriese, E. Airborne contact dermatitis from coleus in a housewife. Contact Dermatitis 1991;25(2):128-129. PubMed
  11. Schlepper, M., Thormann, J., and Mitrovic, V. Cardiovascular effects of forskolin and phosphodiesterase-III inhibitors. Basic Res Cardiol 1989;84 Suppl 1:197-212. PubMed
  12. Dooms-Goossens, A., Borghijs, A., Degreef, H., Devriese, E. G., and Geuns, J. M. Airborne contact dermatitis to Coleus. Contact Dermatitis 1987;17(2):109-110. PubMed
  13. Lindner, E., Dohadwalla, A. N., and Bhattacharya, B. K. Positive inotropic and blood pressure lowering activity of a diterpene derivative isolated from Coleus forskohli: Forskolin. Arzneimittelforschung 1978;28(2):284-289.
  14. Loftus HL, Astell KJ, Mathai ML, et al. Coleus forskohlii Extract Supplementation in Conjunction with a Hypocaloric Diet Reduces the Risk Factors of Metabolic Syndrome in Overweight and Obese Subjects: A Randomized Controlled Trial. Nutrients. 2015;7(11): PubMed
  15. Yokotani K, Chiba T, Sato Y, et al. Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro. J Pharm Pharmacol. 2012;64(12):1793-801.
  16. Nishijima C, Chiba T, Sato Y, Umegaki K. Nationwide Online Survey Enables the Reevaluation of the Safety of Coleus forskohlii Extract Intake Based on the Adverse Event Frequencies. Nutrients. 2019;11(4). pii: E866. PubMed

See these in context on the Coleus monograph →

Guggul 21 references
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Dalvi SS, Nayak VK, Pohujani SM, et al. Effect of gugulipid on bioavailability of diltiazem and propranolol. J Assoc Phys India 1994;42:454-5.
  3. Singh RB, Niaz MA, Ghosh S. Hypolipidemic and antioxidant effects of Commiphora mukul as an adjunct to dietary therapy in patients with hypercholesterolemia. Cardiovasc Drugs Ther 1994;8:659-64. PubMed
  4. Tripathi YB, Tripathi P, Malhotra OP, Tripathi SN. Thyroid stimulatory action of (Z)-guggulsterone: mechanism of action. Planta Med 1988;54:271-7.
  5. Agarwal RC, Singh SP, Saran RK, et al. Clinical trial of gugulipid – a new hypolipidemic agent of plant origin in primary hyperlipidemia. Ind J Med Res 1986;84:626-34.
  6. Malhotra SC, Ahuja MM, Sundaram KR. Long term clinical studies on the hypolipidaemic effect of Commiphora mukul (Guggulu) and clofibrate. Indian J Med Res 1977;65:390-5.
  7. Mester L, Mester M, Nityanand S. Inhibition of platelet aggregation by "guggulu" steroids. Planta Med 1979;37:367-9. PubMed
  8. Szapary PO, Wolfe ML, Bloedon LT, et al. Guggulipid for treatment of hypercholesterolemia: a randomized controlled trial. JAMA 2003;290:765-72.
  9. Brobst DE, Ding X, Creech KL, et al. Guggulsterone activates multiple nuclear receptors and induces CYP3A gene expression through the pregnane X receptor. J Pharmacol Exp Ther 2004;310:528-35. PubMed
  10. Bianchi A, Cantu P, Firenzuoli F, et al. Rhabdomyolysis caused by Commiphora mukul, a natural lipid-lowering agent. Ann Pharmacother 2004;38:1222-5.
  11. Gelfand JM, Crawford GH, Brod BA, Szazpary PO. Adverse cutaneous reactions to guggulipid. J Am Acad Dermatol 2005;52:533-4 PubMed
  12. Nohr, L. A., Rasmussen, L. B., and Straand, J. Resin from the mukul myrrh tree, guggul, can it be used for treating hypercholesterolemia? A randomized, controlled study. Complement Ther.Med. 2009;17(1):16-22. PubMed
  13. Gelfand, J. M., Crawford, G. H., Brod, B. A., and Szazpary, P. O. Adverse cutaneous reactions to guggulipid. J.Am.Acad.Dermatol. 2005;52(3 Pt 1):533-534. PubMed
  14. Kolonte, A., Guillot, B., and Raison-Peyron, N. Allergic contact dermatitis to guggul extract contained in an anticellulite gel-cream. Contact Dermatitis 2006;54(4):226-227. PubMed
  15. Salavert, M., Amarger, S., Le Bouedec, M. C., Roger, H., Souteyrand, P., and D'incan, M. Allergic contact dermatitis to guggul in a slimming cream. Contact Dermatitis 2007;56(5):286-287. PubMed
  16. Malhotra SC, Ahuja MM. Comparative hypolipidaemic effectiveness of gum guggulu (Commiphora mukul) fraction 'A', ethyl-P-chlorophenoxyisobutyrate and Ciba-13437-Su. Indian J Med Res 1971;59:1621-1632.
  17. Gaur SP, Garg RK, Kar AM, et al. Gugulipid, a new hypolipidaemic agent, in patients of acute ischaemic stroke: effect on clinical outcome, platelet function and serum lipids. Asia Pacif J Pharm 1997;12:65-69.
  18. Baldwa VS, Sharma RC, Ranka PC, et al. Effect of Commiphora mukul (guggul) on fibrinolytic activity and platelet aggregation in coronary artery disease. Rajas Med J 1980;19:84-86.
  19. Donato F, Raffetti E, Toninelli G, Festa A, Scarcella C, Castellano M; TRIGU Project Working Group. Guggulu and Triphala for the Treatment of Hypercholesterolaemia: A Placebo-Controlled, Double-Blind, Randomised Trial. Complement Med Res 2021;28(3):216-22 PubMed
  20. Mehdi Z, Fatemeh P, Roja R, et al. Efficacy and safety of Hemoheal cream in patients with hemorrhoids: a randomized double-blind placebo controlled clinical trial. J Tradit Chin Med 2021;41(2):301-307.
  21. Asad M, Asdaq SMB, Mohzari Y, et al. Pharmacokinetic and pharmacodynamic interaction of Rosuvastatin calcium with guggulipid extract in rats. Saudi J Biol Sci 2021;28(6):3490-3496. PubMed

See these in context on the Guggul monograph →

Fucus Vesiculosus 15 references
  1. Goodman GA, Rall TW, Nies AS, Taylor P. The Pharmacological Basis of Therapeutics, 9th ed.
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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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