Herb & supplement monograph

Ascophyllum Nodosum Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Ascophyllum Nodosum interacts with medications. The heart of this page is the interaction list — every drug Ascophyllum Nodosum is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Ascophyllum Nodosum is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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On this page

Ascophyllum Nodosum Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Ascophyllum Nodosum drug interactions are all rated moderate and center almost entirely on its iodine content, so the main risk of a clinically significant interaction falls on people taking thyroid-related medicines rather than most people. None of the listed interactions are rated major, and every one traces back to the same concern: this brown seaweed naturally contains iodine, which can affect thyroid function.

Interactions deserving the most attention

The combination that stands out most is with amiodarone, a heart rhythm drug that is itself very high in iodine; taking both could push iodine levels too high and disturb thyroid function, and this concern has some human support. Thyroid hormone replacement and antithyroid drugs also deserve care, since extra iodine may shift thyroid levels in either direction and make these closely monitored medicines harder to keep steady.

What the rest of the list means

A list of about two dozen medications sounds long, but it reflects one shared mechanism, not many separate dangers. Most of these interactions are theoretical, based on how high-dose iodine can behave, and the iodine in this seaweed is absorbed less readily than iodine from supplements like potassium iodide. Solid human studies confirming harm are lacking.

Check your medications against Ascophyllum Nodosum

Based on HelloPharmacist’s Ascophyllum Nodosum interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Ascophyllum Nodosum

22 medications have a known interaction with Ascophyllum Nodosum, graded by severity. Select any drug for the full evidence-based detail.

2,830 drugs
AmiodaroneCordarone, Pacerone
Moderate Amiodarone (cordarone)

Theoretically, combining Ascophyllum nodosum with amiodarone might cause excessively high iodine levels.

Read the full Ascophyllum Nodosum + Amiodarone interaction Amiodarone drug page: uses, dosage & side effects
CarbimazoleNeo-Mercazole
Moderate Antithyroid Drugs

Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.

Read the full Ascophyllum Nodosum + Carbimazole interaction
Conjugated EstrogensCenestin, Enjuvia, Premarin, Premarin Vaginal Cream
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Conjugated Estrogens interaction
Desiccated Thyroid ExtractWesthroid, WP Thyroid
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Desiccated Thyroid Extract interaction
Desiccated Thyroid Extract (prescription Drug)Nature-Throid, Thyrar
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Desiccated Thyroid Extract (prescription Drug) interaction
DextrothyroxineCholoxin
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Dextrothyroxine interaction
Human Chorionic Gonadotropin (hcg)Pregnyl
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Human Chorionic Gonadotropin (hcg) interaction
LevothyroxineEltroxin, Estre, Euthyrox, Levo-T, Levolet, Levothroid +5 more
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Levothyroxine interaction Levothyroxine drug page: uses, dosage & side effects
Levothyroxine SodiumErmez, Thyquidity, Tirosint-Sol
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Levothyroxine Sodium interaction
Levothyroxine, LiothyronineArmour Thyroid
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Levothyroxine, Liothyronine interaction
LiothyronineCytomel
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Liothyronine interaction Liothyronine drug page: uses, dosage & side effects
LiotrixEuthroid 1, Euthroid 1/2, Euthroid 3
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Liotrix interaction Liotrix drug page: uses, dosage & side effects
Liotrix, T4/t3Euthroid 2
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Liotrix, T4/t3 interaction
MenotropinsMenopur, Repronex
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Menotropins interaction
Methenamine MandelateMandelamine, Methimazole
Moderate Antithyroid Drugs

Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.

Read the full Ascophyllum Nodosum + Methenamine Mandelate interaction Methenamine Mandelate drug page: uses, dosage & side effects
MethimazoleTapazole
Moderate Antithyroid Drugs

Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.

Read the full Ascophyllum Nodosum + Methimazole interaction Methimazole drug page: uses, dosage & side effects
OspemifeneOsphena
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Ospemifene interaction Ospemifene drug page: uses, dosage & side effects
Potassium Iodide (prescription Drug)Thyro-Block
Moderate Antithyroid Drugs

Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.

Read the full Ascophyllum Nodosum + Potassium Iodide (prescription Drug) interaction
Propylthiouracil, PtuPropylthiouracil
Moderate Antithyroid Drugs

Due to its iodine content, Ascophyllum nodosum might alter the effects of antithyroid drugs.

Read the full Ascophyllum Nodosum + Propylthiouracil, Ptu interaction Propylthiouracil, Ptu drug page: uses, dosage & side effects
Testosterone UndecanoateAndriol, Aveed, Jatenzo, Kyzatrex
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Testosterone Undecanoate interaction Testosterone Undecanoate drug page: uses, dosage & side effects
ThyroglobulinProloid
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Thyroglobulin interaction
Thyroid HormoneEtwon
Moderate Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.

Read the full Ascophyllum Nodosum + Thyroid Hormone interaction
"phentolamineOraVerse, Rogitine, Ryzumvi › 6-mercaptopurinePurinethol › Ado-trastuzumab EmtansineKadcyla › AbacavirZiagen › Abacavir Sulfate, Dolutegravir, LamivudineTriumeq › Abacavir, LamivudineEpzicom › AbaloparatideTymlos › AbametapirXeglyze ›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Ascophyllum Nodosum combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Ascophyllum Nodosum affects

Every type of medication (drug category) Ascophyllum Nodosum is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Ascophyllum Nodosum interacts with
Amiodarone (cordarone)Antithyroid DrugsThyroid Hormone
Amiodarone (Cordarone)

Theoretically, combining Ascophyllum nodosum with amiodarone might cause excessively high iodine levels.
Ascophyllum nodosum contains iodine, although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide. 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, Ascophyllum nodosum might alter the effects of antithyroid drugs.
Ascophyllum nodosum contains iodine, although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using antithyroid drugs could alter the effects of the antithyroid drugs.

Likelihood Possible Evidence D
Thyroid Hormone

Due to its iodine content, Ascophyllum nodosum might alter the effects of thyroid hormone.
Ascophyllum nodosum contains iodine, although the bioavailability of iodine from Ascophyllum nodosum is lower than that of potassium iodide. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking Ascophyllum nodosum while using thyroid hormone could alter the effects of thyroid hormone.

Likelihood Possible Evidence D
Monograph

Ascophyllum Nodosum: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Ascophyllum nodosum (often sold as bladderwrack or brown seaweed) is a nutrient-rich algae that people use for weight, blood sugar, and thyroid support, but solid human evidence is limited for most of these uses. Because it naturally contains iodine and can absorb heavy metals like arsenic, it should be used cautiously, and pregnant or breastfeeding people should avoid it unless a doctor approves.

Ascophyllum Nodosum
Scientific name
Ascophyllum nodosum
Family
Fucaceae
Part used
Whole seaweed (thallus/fronds)
Common forms
Capsules, tablets, powder, extracts, teas, and topical products
People commonly use it for
  • Weight management
  • Blood sugar support
  • Thyroid support (iodine source)
  • Digestive health
  • Source of vitamins and minerals
  • Joint comfort

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallUse caution

Generally used in foods, but its iodine content and possible heavy metal contamination warrant caution.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using amounts greater than those found in food.

Read the full pregnancy detail
BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using amounts greater than those found in food.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Ascophyllum nodosum is a type of brown seaweed, also widely known as bladderwrack, knotted wrack, or egg wrack. It grows along cold, rocky shorelines in the North Atlantic, including parts of Europe, Iceland, Greenland, the northeastern United States, and eastern Canada.

This seaweed has long been used as food, animal feed, and fertilizer. As a supplement, it is sold in capsules, powders, teas, and extracts. People take it for many reasons, often because it is naturally rich in nutrients such as iodine, minerals, and plant compounds called polysaccharides and phlorotannins.

How it works

Ascophyllum nodosum contains several compounds that researchers find interesting. Fucoidans and laminarin are polysaccharides (complex sugars) that may act on the immune system and gut. Phlorotannins are antioxidant compounds found only in brown seaweed.

In laboratory studies, some of these compounds appear to block enzymes that digest carbohydrates and fats, which is one proposed way the seaweed might affect blood sugar and weight. It also provides iodine, a mineral the thyroid needs to make hormones.

It is important to know that much of this research comes from test tube and animal studies. What happens in a lab does not always translate to real benefits in people.

Effectiveness

Does Ascophyllum Nodosum work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 9 uses evaluated
9 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For Ascophyllum Nodosum, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 9 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Dental plaque
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque.

Insufficient Reliable Evidence To Rate Gastroesophageal reflux disease (GERD)
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral Ascophyllum nodosum for GERD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.

Insufficient Reliable Evidence To Rate Gingivitis
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral Ascophyllum nodosum is beneficial in patients with dental plaque.

Insufficient Reliable Evidence To Rate Impaired glucose tolerance (prediabetes)
Rating & evidence shown verbatim from Natural Medicines

Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Inflammatory bowel disease (IBD)
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral Ascophyllum nodosum for IBD, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.

Insufficient Reliable Evidence To Rate Iodine deficiency
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral Ascophyllum nodosum is beneficial in patients with iodine deficiency.

Insufficient Reliable Evidence To Rate Metabolic syndrome
Rating & evidence shown verbatim from Natural Medicines

Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Obesity
Rating & evidence shown verbatim from Natural Medicines

Oral Ascophyllum nodosum has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

Insufficient Reliable Evidence To Rate Peptic ulcers
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral Ascophyllum nodosum for peptic ulcers, there is insufficient reliable information about the clinical effects of Ascophyllum nodosum for this purpose.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

When eaten in normal food amounts, brown seaweed is generally considered safe for most healthy adults. As a concentrated supplement, there are some important cautions.

Iodine: Ascophyllum nodosum can contain large and variable amounts of iodine. Too much iodine may trigger or worsen thyroid problems, including both underactive and overactive thyroid. People with thyroid disease should be especially careful.

Heavy metals: Seaweed naturally absorbs minerals from seawater, including arsenic, cadmium, and other heavy metals. Contaminated products have been reported, so choosing a tested, reputable brand matters.

Pregnancy and breastfeeding: Avoid using this supplement. The high and unpredictable iodine content and possible contaminants could harm a developing baby or pass into breast milk.

Talk to your pharmacist or doctor before starting, especially if you have a thyroid condition, kidney disease, or take any medicines.

Side effects

Reported side effects are usually mild and may include stomach upset, bloating, or digestive changes. Because of its iodine content, regular use may affect thyroid function and could cause symptoms such as a change in energy, weight, or heart rate over time.

Rarely, contaminated products have been linked to heavy metal exposure, including arsenic. Allergic reactions to seaweed are also possible. Stop use and seek medical care if you have signs of an allergic reaction or unexplained symptoms.

Ascophyllum Nodosum: Reported Adverse Effects

Documented safety reports on Ascophyllum Nodosum from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Reports by condition
Myasthenia gravis Endocrine

Orally, taking Ascophyllum nodosum powder 500 mg daily for 14 days has been reported to cause elevated levels of thyroid stimulating hormone (TSH) in 2 of 22 women in a clinical trial. The powder contained 356 mcg iodine per 500 mg. Levels of free thyroxine (T4) were unaffected.

  1. Combet E, Ma ZF, Cousins F, et al. Low-level seaweed supplementation improves iodine status in iodine-insufficient women. Br J Nutr 2014;112:753-61.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no well-established standard dose of Ascophyllum nodosum. Products vary widely in strength and iodine content, which makes consistent dosing difficult.

If you choose to use it, follow the directions on the product label and do not exceed the recommended amount. Because of the iodine concern, it is wise to check with a pharmacist or doctor first, particularly to avoid getting too much iodine from all your supplements combined.

Pregnancy & Breastfeeding

Ascophyllum Nodosum & Pregnancy

Insufficient reliable information

Insufficient reliable information available; avoid using amounts greater than those found in food.

Ascophyllum Nodosum & Breastfeeding

Insufficient reliable information

Insufficient reliable information available; avoid using amounts greater than those found in food.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 5 references that drive our Ascophyllum Nodosum monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  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. Sterling JB, Heymann WR. Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications. J Am Acad Dermatol 2000;43:691-7. PubMed
  3. Combet E, Ma ZF, Cousins F, et al. Low-level seaweed supplementation improves iodine status in iodine-insufficient women. Br J Nutr 2014;112:753-61. PubMed
  4. Simmons-Boyce JL, Purcell SL, Nelson CM, MacKinnon SL. Dietary Ascophyllum nodosum increases urinary excretion of tricarboxylic acid cycle intermediates in male Sprague-dawley rats. J Nutr 2009;139:1487-94. PubMed
  5. Sorge US, Henriksen M, Bastan A, et al. Short communication: Iodine concentrations in serum, milk, and tears after feeding Ascophyllum nodosum to dairy cows-A pilot study. J Dairy Sci 2016;99:8472-6. PubMed
Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

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

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Ascophyllum Nodosum

87 brands in our database make a supplement containing Ascophyllum Nodosum.

Product directory

Supplement products with Ascophyllum Nodosum

363 products in our database contain Ascophyllum Nodosum. Open any to see its full ingredient list and every drug interaction we check.

A.C.S. by Pure Herbs Capsule 150 Capsule(s) View ingredients & interactions A.C.S. by Pure Herbs Capsule 150 Capsule(s) View ingredients & interactions Accelerator by Custom Health Centers Capsule 60 Vegan Capsule(s) View ingredients & interactions Advanced Multiple by BodSmith Liquid 1 Quart(s) · 32 Fluid Ounce(s) · 946 mL View ingredients & interactions Advanced Superfood Greens & Vegetables Berry Flavored by H!D Hallelujah Diet Powder 8.5 Ounce(s) · 240 Gram(s) View ingredients & interactions Advanced Superfood Greens & Vegetables Plain by H!D Hallelujah Diet Powder 8.5 Ounce(s) · 240 Gram(s) View ingredients & interactions Age Defying Formula by California Academy of Health Liquid 32 Fluid Ounce(s) · 946 mL View ingredients & interactions All Day Energy Greens by IVL Powder 10.5 Ounce(s) · 300 Gram(s) View ingredients & interactions All Day Energy Greens Fruity by IVL Powder 10.5 Ounce(s) · 300 Gram(s) View ingredients & interactions Arnold Iron Pack by Arnold Schwarzenegger Series Other (e.g. Tea Bag) 30 Pack(s) View ingredients & interactions Arnold Iron Pack by MusclePharm Other (e.g. Tea Bag) View ingredients & interactions B-Complex by Natural Nutra Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Beautiful Hair & Nails by Crystal Star Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Berberine with InSea2 by XYMOGEN Capsule 60 Vegetarian Capsule(s) View ingredients & interactions C8 To T1 Thy by Chiro-Zyme Capsule 180 Capsule(s) View ingredients & interactions Cardio Cuts 4.0 Bombsicle Explosion by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Cardio Cuts 4.0 Grape Gusher by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Cardio Cuts 4.0 Gummy Candy Rush by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Cardio Cuts 4.0 Peach Mango by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Cardio Cuts 4.0 Raspberry Lemonade by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Cardio Cuts 4.0 Strawberry Watermelon by NDS Nutrition Powder 8.6 Ounce(s) · 244 Gram(s) View ingredients & interactions Colon Cleanser by Herb Stop Capsule 300 Veggie Capsule(s) View ingredients & interactions Complete Foods Multi by Trace Minerals Research Tablet Or Pill 120 Tablet(s) View ingredients & interactions Complete Multiple Natural Berry Flavor by Liquid Health Liquid 32 fl. Oz. · 946 mL View ingredients & interactions
Pharmacist Counseling Corner

Ascophyllum Nodosum: Common Questions

What is Ascophyllum Nodosum used for, and does it work?
People use Ascophyllum Nodosum for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Ascophyllum Nodosum interact with prescription medications?
Yes. We list 22 medications with a known interaction with Ascophyllum Nodosum. Use the checker above to see how Ascophyllum Nodosum interacts with a specific drug.
How are Ascophyllum Nodosum interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Ascophyllum Nodosum with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Ascophyllum Nodosum interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
Is Ascophyllum Nodosum the same as bladderwrack and kelp?
Ascophyllum Nodosum is often sold under the name bladderwrack and is sometimes loosely called kelp, though true kelps are different species. Many products list several of these names interchangeably.
What do people use Ascophyllum Nodosum for?
People commonly use it for weight management, blood sugar support, thyroid support, and as a source of minerals like iodine. However, strong human evidence is lacking for most of these uses.
Can I take it for thyroid problems?
It is not a safe or reliable thyroid treatment. Its iodine content is high and unpredictable, and too much iodine can actually worsen thyroid problems, so talk to your doctor first.
Is it safe during pregnancy or breastfeeding?
No, it is best to avoid it. The high iodine levels and possible heavy metal contamination could harm a baby or pass into breast milk.

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

Keep exploring

Products that contain Ascophyllum Nodosum

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See all 363 products with Ascophyllum Nodosum →
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