Interactions on record — worth a quick check against your medications. Based on 2 of 3 ingredients. Check your meds →
Dietary supplement

Kelp Ingredients & Drug Interactions

by Herb Xtra

Kelp label
See full label image
Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Kelp 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: Moderate

Kelp is a dietary supplement by Herb Xtra with 3 active ingredients. Its ingredients are commonly taken for joint and bone health, skin, hair, and nail support, source of dietary protein.Based on those ingredients, 891 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Kelp. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Kelp by Herb Xtra

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

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HelloPharmacist Scorecard of Kelp by Herb Xtra

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 Aug 13, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 3 active ingredients.

This product contains 3 ingredients: gelatin (the capsule itself), water, and kelp. Kelp, also known as Fucus vesiculosus, is a seaweed rich in iodine and other minerals.

The product has no other inactive ingredients listed.

Does it work?

Couldn't assess
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
Not assessable

The label doesn't state a purpose we can grade — see each ingredient's own graded uses on its monograph instead.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

The evidence for kelp isn't established in the data we hold. Gelatin shows insufficient evidence for aging skin, brittle nails, beta-thalassemia, and uterine fibroids, and is rated possibly ineffective for diarrhea.

Kelp similarly lacks reliable evidence for cardiovascular health, constipation, diarrhea, or upset stomach (dyspepsia). If you're considering this for a specific health goal, talk with your doctor or pharmacist about whether the evidence supports it.

The evidence, ingredient by ingredient Gelatin 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 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Gelatin is well tolerated by mouth in most people, though it can cause belching, bloating, and upset stomach (dyspepsia). It's considered likely safe during pregnancy and lactation in food amounts, but talk with your doctor before taking supplement doses while pregnant or breastfeeding.

Kelp, however, carries cautions because of its variable and high iodine content—it can disrupt thyroid function and may concentrate heavy metals. The safety data advises against kelp use during pregnancy and breastfeeding; iodine passes into breast milk and may affect your baby's thyroid.

Gelatin can trigger allergic reactions in sensitive people, including rare cases of severe reactions (anaphylaxis) or swelling of the throat (angioedema). Kelp can cause goiter, overactive thyroid, underactive thyroid, and in rare cases thyroid cancer.

Side effects, ingredient by ingredient Gelatin Fucus Vesiculosus

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 2 matched ingredients can interact with medications — Fucus Vesiculosus.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; lithium.
  • For scale: 892 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.

Check with your doctor or pharmacist before taking this product if you use lithium, antithyroid drugs, amiodarone, or thyroid hormone replacements—these are at Moderate risk due to kelp's iodine content. You should also verify blood thinners, antiplatelet drugs, and medications broken down by cytochrome P450 enzymes (many antidepressants, diabetes drugs, and pain relievers), though the risk is lower.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Kelp by Herb Xtra is mainly a concern if you take thyroid medications, heart medications like amiodarone, mood stabilizers like lithium, or blood thinners. The high iodine content makes it unsafe during pregnancy and breastfeeding.

Talk with your doctor or pharmacist before starting it, especially if you have thyroid disease or take any prescription medications.

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

Assessment coverage: 2 of 3 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jan 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 Kelp, straight from the product label.

Brand Herb Xtra
Barcode (UPC) 777949998735
Net contents 100 Capsule(s); 450 mg
Market status On market
Date entered into DSLD Jan 25, 2013
DSLD ID 17565
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Kelp by Herb Xtra, 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 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
UPC/BARCODE
777949998735
IngredientAmount% DV
Gelatin0 NP--
Water0 NP--
Kelp0 NP--

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

Use: As a Herbal Supplement: 1 capsule 3 times daily with a glass of water.

General

H340400

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

See for yourself

Kelp by Herb Xtra label

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

Kelp 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 Kelp by Herb Xtra

These are the 3 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule 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.

Gelatin

No known
interactions
0 NP per serving

Gelatin is a protein made from animal collagen, used as a food, a capsule ingredient, and a supplement for joint, skin, and bone health. For most heal...

Gelatin monograph & interactions

Water

0 NP per serving

Kelp

Interacts with
891 drugs
0 NP per serving

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

Kelp monograph & interactions
Interaction report

Kelp by Herb Xtra Drug Interactions

Want to check YOUR meds against Kelp?

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
891Drugs
23 Moderate 868 Minor

Ingredients driving the most interactions

Kelp 891

Individual Drug Interactions

The ingredients in Kelp interact with 891 drugs. Click any drug to see the details.

1 of the 3 ingredients in Kelp interact with drugs. Each result below shows which ingredient is responsible. Kelp

Each ingredient & the kinds of drugs it affects

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

Kelp9 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
Kelp full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Kelp, from the product label.

Herb Xtra

See all Herb Xtra products
Name
GOURMET NUTRITION F.B. INC.
City
STE-JULIE
State
QUEBEC
ZipCode
J3E 1Z2
Pharmacist Counseling Corner

Kelp by Herb Xtra: Common Questions

Does Kelp by Herb Xtra interact with any medications?
Yes. Based on its ingredients, Kelp has a known interaction with 891 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Kelp contains 3 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm pregnant or breastfeeding?
No. The safety data advises against kelp use during pregnancy and breastfeeding because of its iodine content, which can affect your thyroid and your baby's thyroid. Talk with your doctor about alternatives.
What's gelatin, and is it a problem?
Gelatin is the capsule material—it's widely eaten in foods and is generally well tolerated. However, it can cause belching, bloating, and upset stomach, and rarely triggers allergic reactions in sensitive people.
Does this product actually work for anything?
The evidence we hold doesn't establish effectiveness for any of the conditions it might be used for—aging skin, cardiovascular health, constipation, or diarrhea all lack reliable evidence.
What are the main side effects I should watch for?
From the kelp: goiter, overactive or underactive thyroid. From the gelatin: belching, bloating, and upset stomach. Allergic reactions to gelatin are rare but can be serious.
Why is this a problem with thyroid medications?
Kelp is loaded with iodine, which your body uses to make thyroid hormone. Too much can throw your thyroid out of balance—either overactive or underactive—and can interfere with how your thyroid drugs work.

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.

Kelp label
Go deeper

The Full Monographs Behind Kelp’s Ingredients

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

Herb & supplement monograph

Gelatin

Gelatin is a protein made from animal collagen, used as a food, a capsule ingredient, and a supplement for joint, skin, and bone health. For most health uses, the evidence is limited or mixe...

Read the full Gelatin 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

Kelp'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 26 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.

Gelatin 11 references
  1. Lewis CJ. Letter to reiterate certain public health and safety concerns to firms manufacturing or importing dietary supplements that contain specific bovine tissues. FDA. Available at: www.cfsan.fda.gov/~dms/dspltr05.html.
  2. Schwick HG, Heide K. Immunochemistry and immunology of collagen and gelatin. Bibl Haematol 1969;33:111-25. PubMed
  3. Moskowitz RW. Role of collagen hydrolysate in bone and joint disease.Semin Arthritis Rheum 2000;30:87-99. PubMed
  4. Kelso JM. The gelatin story. J Allergy Clin Immunol 1999;103:200-2.
  5. Nakayama T, Aizawa C, Kuno-Sakai H. A clinical analysis of gelatin allergy and determination of its causal relationship to the previous administration of gelatin-containing acellular pertussis vaccine combined with diphtheria and tetanus toxoids. J Allerg PubMed
  6. Sakaguchi M, Inouye S. Anaphylaxis to gelatin-containing rectal suppositories. J Allergy Clin Immunol 2001;108:1033-4. PubMed
  7. PDR Electronic Library. Montvale, NJ: Medical Economics Company, Inc., 2001.
  8. de la Fuente Tornero E, Vega Castro A, de Sierra Hernández PÁ, et al. Kounis syndrome during anesthesia: Presentation of indolent systemic mastocytosis: A case report. A Case Rep. 2017;8(9):226-228. PubMed
  9. Ventura Spagnolo E, Calapai G, Minciullo PL, Mannucci C, Asmundo A, Gangemi S. Lethal anaphylactic reaction to intravenous gelatin in the course of surgery. Am J Ther. 2016;23(6):e1344-e1346. PubMed
  10. Li Y, He H, Yang L, Li X, Li D, Luo S. Therapeutic effect of Colla corii asini on improving anemia and hemoglobin compositions in pregnant women with thalassemia. Int J Hematol. 2016;104(5):559-565. PubMed
  11. Coury JR, Skaggs KF, Marciano GF, et al. Intraoperative Anaphylaxis to the Bovine Flowable Gelatin Matrix: A Report of 2 Cases. JBJS Case Connect 2022;12(1). PubMed

See these in context on the Gelatin monograph →

Fucus Vesiculosus 15 references
  1. Goodman GA, Rall TW, Nies AS, Taylor P. The Pharmacological Basis of Therapeutics, 9th ed.
  2. 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.
  3. Phaneuf D, Cote I, Dumas P, et al. Evaluation of the contamination of marine algae (Seaweed) from the St. Lawrence River and likely to be consumed by humans. Environ Res 1999;80:S175-S182. PubMed
  4. Durig J, Bruhn T, Zurborn KH, et al. Anticoagulant fucoidan fractions from Fucus vesiculosus induce platelet activation in vitro. Thromb Res 1997;85:479-91. PubMed
  5. Conz PA, La Greca G, Benedetti P, et al. Fucus vesiculosus: a nephrotoxic alga? Nephrol Dial Transplant 1998;13:526-7.
  6. Ohye H, Fukata S, Kanoh M, et al. Thyrotoxicosis caused by weight-reducing herbal medicines. Arch Intern Med 2005;165:831-4. PubMed
  7. Okamura K, Inoue K, Omae T. A case of Hashimoto's thyroiditis with thyroid immunological abnormality manifested after habitual ingestion of seaweed. Acta Endocrinol (Copenh) 1978;88:703-12. PubMed
  8. Agarwal SC, Crook JR, Pepper CB. Herbal remedies -- how safe are they? A case report of polymorphic ventricular tachycardia/ventricular fibrillation induced by herbal medication used for obesity. Int J Cardiol 2006;106:260-1. PubMed
  9. 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
  10. Catania, M. A., Oteri, A., Caiello, P., Russo, A., Salvo, F., Giustini, E. S., Caputi, A. P., and Polimeni, G. Hemorrhagic cystitis induced by an herbal mixture. South.Med.J. 2010;103(1):90-92. PubMed
  11. Cumashi, A., Ushakova, N. A., Preobrazhenskaya, M. E., D'Incecco, A., Piccoli, A., Totani, L., Tinari, N., Morozevich, G. E., Berman, A. E., Bilan, M. I., Usov, A. I., Ustyuzhanina, N. E., Grachev, A. A., Sanderson, C. J., Kelly, M., Rabinovich, G. A., I
  12. Irhimeh, M. R., Fitton, J. H., and Lowenthal, R. M. Pilot clinical study to evaluate the anticoagulant activity of fucoidan. Blood Coagul.Fibrinolysis 2009;20(7):607-610. PubMed
  13. Arbaizar, B. and Llorca, J. [Fucus vesiculosus induced hyperthyroidism in a patient undergoing concomitant treatment with lithium]. Actas Esp.Psiquiatr. 2011;39(6):401-403.
  14. Church FC, Meade JB, Treanor RE, and et al. Antithrombin activity of fucoidan. The interaction of fucoidan with heparin cofactor II, antithrombin III, and thrombin. J Biol Chem 2-25-1989;264(6):3618-3623. DOI
  15. Mathew L, Burney M, Gaikwad A, et al. Preclinical evaluation of safety of fucoidan extracts from Undaria pinnatifida and Fucus vesiculosus for use in cancer treatment. Integr Cancer Ther 2017;16(4):572-84.

See these in context on the Fucus Vesiculosus monograph →

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

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