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Dietary supplement

Kelp Extract Ingredients & Drug Interactions

by BulkSupplements.com

Kelp Extract label
See full label image
Powder Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Kelp Extract 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 Extract is a dietary supplement by BulkSupplements.com with 1 active ingredient. Its ingredients are commonly taken for source of dietary iodine, thyroid support, cervical dilation (medical procedure).Based on those ingredients, 69 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Kelp 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 Kelp Extract by BulkSupplements.com

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

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HelloPharmacist Scorecard of Kelp Extract by BulkSupplements.com

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

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 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product is a single-ingredient powder: kelp extract. Kelp is a seaweed that concentrates minerals and iodine from ocean water.

That high iodine content is why it interacts with thyroid and heart medications. There are no 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

This is a single-ingredient Laminaria product and its label doesn't state a use — see Laminaria's own graded uses on its monograph.

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

The evidence we hold on kelp extract is limited. We don't have enough reliable data to rate it for high blood pressure, weight loss, cancer, or radiation exposure.

For pregnancy-related uses (abortion and labor), the data suggests it's likely ineffective.

The evidence, ingredient by ingredient Laminaria

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 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Kelp is generally well tolerated as a food, but supplements deliver very high and unpredictable amounts of iodine that can affect your thyroid. One serious concern: kelp concentrates arsenic from seawater.

A case in our data showed that several months of taking an oral kelp supplement led to arsenic poisoning—headaches, weakness, memory loss, skin rash, nail damage, diarrhea, and vomiting. Arsenic levels vary widely between batches and depend on where the kelp was harvested.

Orally, some people have reported acne linked to kelp use. If you're pregnant, kelp supplements are best avoided unless your doctor directs it—excess iodine can harm the fetal thyroid.

If you're breastfeeding, avoid concentrated kelp supplements because iodine passes into breast milk and high amounts may affect your baby's thyroid.

Side effects, ingredient by ingredient Laminaria

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 1 matched ingredient can interact with medications — Laminaria.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: heart-rhythm medications.
  • For scale: 69 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 kelp, check with your doctor or pharmacist if you're on antithyroid medications, thyroid hormone replacement, amiodarone (a heart rhythm drug), ACE inhibitors, potassium-sparing diuretics, or digoxin. All of these have documented moderate-severity interactions with kelp's potassium and iodine content.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Kelp extract is worth considering if you're interested in seaweed-based supplements, but it's not a first choice if you take blood pressure drugs, heart medications, thyroid drugs, or water pills. The variable iodine and arsenic content adds real uncertainty.

Talk with your pharmacist or doctor before starting, especially if you have thyroid issues or take any of the medications listed in the Med Watch section below.

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

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Sep 24, 2021.

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

At a glance

General information

Key facts about Kelp Extract, straight from the product label.

Brand BulkSupplements.com
Barcode (UPC) X001FEYQC9
Net contents 250 Gram(s); 8.8 Ounce(s)
Market status On market
Date entered into DSLD Sep 24, 2021
DSLD ID 255055
Product type Non-nutrient/non-botanical
Supplement form Powder
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, 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 Kelp Extract by BulkSupplements.com, 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:
500 mg
Maximum serving Sizes:
500 mg
Servings per container
500
UPC/BARCODE
X001FEYQC9
IngredientAmount% DV
Kelp extract500 mg--

Other ingredients: None

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.
General Statements

Clean & pure bulk supplements

New - Bulksupplements Kelp Extract (Seaweed) Powder (250 Grams)

Formulation

Free of: Added sugar, soy, dairy, yeast, gluten.

Color may vary

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take 500 mg (about 1/5 tsp) once daily, or as directed by a physician.

Storage

Store in a dry, cool place.

FDA Disclaimer Statement

Warning: This product is not intended to diagnose, treat, cure, or prevent any disease.

Precautions

Always consult a physician before taking any dietary supplement.

Keep out of reach of children.

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

See for yourself

Kelp Extract by BulkSupplements.com label

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

Kelp Extract 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 Extract by BulkSupplements.com

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size500 mg Dosage formPowder Servings per container500 Amounts shown are per serving.

Kelp extract

Interacts with
69 drugs
500 mg per serving

Laminaria is a type of brown seaweed (kelp) that is very rich in iodine and is also used in medical settings as a natural cervical dilator. Because it...

Kelp extract monograph & interactions

Other (inactive) ingredients: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

Kelp Extract by BulkSupplements.com Drug Interactions

Want to check YOUR meds against Kelp Extract?

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
69Drugs
69 Moderate

Ingredients driving the most interactions

Kelp extract 69

Individual Drug Interactions

The ingredients in Kelp Extract interact with 69 drugs. Click any drug to see the details.

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

Each ingredient & the kinds of drugs it affects

For each ingredient in Kelp Extract 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.

Kelp extract6 drug types · 69 drugs

Ace Inhibitors (Aceis)

Theoretically, laminaria might increase the risk of hyperkalemia when taken with ACEIs.
Laminaria contains potassium.

Likelihood Possible Evidence D
Amiodarone (Cordarone)

Theoretically, combining laminaria with amiodarone might cause excessively high iodine levels.
Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use with laminaria supplements, some of which may contain as much as 1000 mcg iodine, might increase the risk of adverse effects from iodine, including altered thyroid function.

Likelihood Possible Evidence D
Antithyroid Drugs

Due to its iodine content, laminaria might alter the effects of antithyroid drugs.
Some laminaria supplements contain up to 1000 mcg of iodine. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking laminaria could theoretically alter the effects of antithyroid drugs.

Likelihood Possible Evidence D
Digoxin (Lanoxin)

Theoretically, laminaria might increase the risk of hyperkalemia, which could increase the effects and adverse effects of digoxin.
Laminaria contains potassium.

Likelihood Possible Evidence D
Potassium-Sparing Diuretics

Theoretically, laminaria might increase the risk of hyperkalemia when taken with potassium-sparing diuretics.
Laminaria contains potassium.

Likelihood Possible Evidence D
Thyroid Hormone

Due to its iodine content, laminaria might alter the effects of thyroid hormone.
Some laminaria supplements contain up to 1000 mcg of iodine. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking laminaria could theoretically alter the effects of thyroid hormone.

Likelihood Possible Evidence D
Kelp extract full monograph & interactions
The maker

Brand information

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

BulkSupplements.com

See all BulkSupplements.com products
Name
BulkSupplements.com
Street Address
7511 Eastgate Rd
City
Henderson
State
NV
ZipCode
89011
Web Address
BulkSupplements.com
Pharmacist Counseling Corner

Kelp Extract by BulkSupplements.com: Common Questions

Does Kelp Extract by BulkSupplements.com interact with any medications?
Yes. Based on its ingredients, Kelp Extract has a known interaction with 69 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Kelp Extract contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is kelp safe if I'm pregnant or breastfeeding?
No—safety data advises against kelp supplements in pregnancy because excess iodine can harm the fetal thyroid. If you're breastfeeding, avoid concentrated kelp supplements too, since iodine passes into breast milk and high amounts may affect your baby's thyroid. Talk with your doctor if you're wondering about kelp in either situation.
Why does kelp interact with so many medications?
Kelp is packed with potassium and iodine—two powerful minerals. High potassium can raise your blood potassium to unsafe levels when combined with certain blood pressure and heart drugs. High iodine can disrupt thyroid function and interfere with how thyroid and heart medications work.
What side effects should I watch for?
Most people tolerate kelp orally without obvious symptoms, but there's a serious concern: kelp concentrates arsenic from seawater. One case documented arsenic poisoning from several months of use, with symptoms like headaches, weakness, memory loss, rash, nail damage, diarrhea, and vomiting. Arsenic levels vary unpredictably between batches. Some people have also reported acne.
How much iodine is in kelp extract?
Kelp supplements can contain up to 1,000 mcg of iodine per dose. That's very high—far more than you'd get from food—and it's why kelp can interfere with thyroid and heart medications. The exact amount varies between batches, which is part of the problem.
Does kelp work for weight loss or blood pressure?
We don't have enough reliable evidence to say whether kelp works for weight loss or high blood pressure. The data we hold is insufficient to rate it for either use.

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 Extract label
Go deeper

The Full Monographs Behind Kelp Extract’s Ingredients

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

Herb & supplement monograph

Laminaria

Interacts with 69 drugs

Laminaria is a type of brown seaweed (kelp) that is very rich in iodine and is also used in medical settings as a natural cervical dilator. Because its iodine content can be high and variabl...

Read the full Laminaria monograph →
Sources

Sources & How We Checked

Kelp Extract'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 9 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.

Laminaria 9 references
  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Pye KG, Kelsey SM, House IM, et al. Severe dyserythropoeisis and autoimmune thrombocytopenia associated with ingestion of kelp supplement. Lancet 1992;339:1540.
  4. Kazzi GM, Bottoms SF, Rosen MG. Efficacy and safety of Laminaria digitata for preinduction ripening of the cervix. Obstet Gynecol 1982;60:440-3..
  5. Harrell BL, Rudolph AH. Letter: Kelp diet: A cause of acneform eruption. Arch Dermatol 1976;112:560.
  6. Eliason BC. Transient hyperthyroidism in a patient taking dietary supplements containing kelp. J Am Board Fam Pract 1998;11:478-80. PubMed
  7. Norman JA, Pickford CJ, Sanders TW, Waller M. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam 1988;5:103-9.. PubMed
  8. Amster E, Tiwary A, Schenker MB. Case report: potential arsenic toxicosis secondary to herbal kelp supplement. Environ Health Perspect 2007;115:606-8. PubMed
  9. Miyai K, Tokushige T, Kondo M; Iodine Research Group. Suppression of thyroid function during ingestion of seaweed "Kombu" (Laminaria japonoca) in normal Japanese adults. Endocr J. 2008 Dec;55(6):1103-8. Epub 2008 Aug 9.

See these in context on the Laminaria 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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