Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Kelp 100 mg Ingredients & Drug Interactions

by Windmill

Kelp 100 mg label
See full label image
Tablet Or Pill Category: Mineral
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 100 mg 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 100 mg is a dietary supplement by Windmill with 1 active ingredient. Its ingredients are commonly taken for preventing iodine deficiency, supporting thyroid hormone production, general energy and metabolism support.Based on those ingredients, 23 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Iodine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Kelp 100 mg by Windmill

Ask about any prescription or over-the-counter medication and we check it for interactions with Kelp 100 mg by Windmill — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Kelp 100 mg by Windmill

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.
  • “Iodine” is listed as a grouped ingredient — the label gives one combined amount (150 mcg) without saying how much of each component you get.

Windmill Kelp contains one active ingredient: kelp (Ascophyllum nodosum), a type of seaweed that naturally supplies iodine. The tablet also includes several inactive ingredients — dicalcium phosphate, brewer's yeast, microcrystalline cellulose, alfalfa, stearic acid, and magnesium stearate — which are used as fillers, binders, and flow agents to hold the tablet together.

Does it work?

Insufficient 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
Insufficient

There isn't enough reliable clinical evidence to rate this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: iodine supplementation for thyroid support.
  • We looked for evidence on: Iodine deficiency, Radiation exposure, Hypothyroidism, Goiter.
  • The closest evidence on file: Ascophyllum Nodosum is rated "Insufficient Reliable Evidence To Rate" for Iodine deficiency (Natural Medicines).

The evidence supporting kelp for its commonly cited uses — iodine deficiency, prediabetes (impaired glucose tolerance), weight management (obesity), reflux (GERD), and inflammatory bowel disease — is currently insufficient in the data we hold. That means we don't have enough reliable clinical evidence to rate whether it works for any of these purposes.

If you're considering kelp for a specific health goal, talk it over with your doctor or pharmacist to see whether the evidence (or lack of it) makes sense for your situation.

The evidence, ingredient by ingredient Iodine Ascophyllum Nodosum

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 when used as a food ingredient, but its iodine content and the risk of heavy metal contamination from the seaweed itself warrant caution. In one small clinical trial, a small number of participants taking kelp powder (500 mg daily for two weeks) showed a rise in thyroid stimulating hormone (TSH), a sign of thyroid stress, although their free thyroxine (T4) remained normal.

During pregnancy, the safety data advises against using kelp because high iodine levels and contaminants could affect the developing baby. During breastfeeding, the data also advises against it because iodine and contaminants pass into breast milk and may reach your baby.

Talk with your doctor or pharmacist about whether kelp is right for you in these situations.

Side effects, ingredient by ingredient Iodine Ascophyllum Nodosum

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 — Ascophyllum Nodosum.
  • The most serious interaction on file is rated Moderate.
  • For scale: 22 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 Windmill Kelp, double-check with your doctor or pharmacist if you're on any of these: antithyroid drugs (used to treat overactive thyroid), thyroid hormone replacement (levothyroxine and similar), or amiodarone (a heart rhythm medication). All three interact with kelp's iodine content at Moderate severity, and the effects depend on your individual thyroid sensitivity.

Check your own medication Run your meds through the checker above

The bottom line

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

Windmill Kelp is an iodine source from seaweed, but evidence for its effectiveness against common health concerns like prediabetes, weight, reflux, or bowel inflammation is not yet established. If you take antithyroid drugs, thyroid hormone replacement, or amiodarone, you'll want to check with your doctor or pharmacist before adding this product — the iodine could interfere with how these medications work.

During pregnancy or breastfeeding, the safety data advises against it.

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 Mar 23, 2012.

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 100 mg, straight from the product label.

Brand Windmill
Barcode (UPC) 035046002985
Net contents 200 Tablet(s)
Market status On market
Date entered into DSLD Mar 23, 2012
DSLD ID 7258
Product type Mineral
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Sugar 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 100 mg by Windmill, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
UPC/BARCODE
035046002985
IngredientAmount% DV
Iodine150 mcg100%
Kelp (Ascophyllum nodosum) (algae)100 mg--

Other ingredients: Dicalcium Phosphate, brewer's yeast, Microcrystalline Cellulose, Alfalfa, Stearic Acid, Magnesium Stearate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formula

Contains Gluten.

General

ITEM #298 Tracking #01762002

Suggested/Recommended/Usage/Directions

Directions: Take one tablet daily as a dietary supplement or as directed by a healthcare professional.

Precautions

KEEP OUT OF REACH OF CHILDREN.

DO NOT PURCHASE IF SEAL IS BROKEN.

Storage

Protect from heat, light and moisture. Store at 15-30(0)C (59-86(0)F).

General Statements

MADE IN U.S.A.

Helps Support Metabolism*

NATURAL SOURCE OF IODINE

FDA Disclaimer Statement

*This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Formulation

NO SUGAR, STARCH, CORN, WHEAT, MILK, SOY, ARTIFICIAL COLORS, FLAVORS OR PRESERVATIVES

FDA Statement of Identity

DIETARY SUPPLEMENT

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

See for yourself

Kelp 100 mg by Windmill label

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

Kelp 100 mg 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 100 mg by Windmill

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

Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.

Iodine

Interacts with
7 drugs
150 mcg per serving

Iodine is an essential mineral your body needs to make thyroid hormones, and most people get enough from iodized salt, dairy, and seafood. Supplements...

Iodine monograph & interactions

Other (inactive) ingredients: Dicalcium Phosphate, Brewer's yeast, Microcrystalline Cellulose, Alfalfa, Stearic Acid, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Kelp 100 mg by Windmill Drug Interactions

Want to check YOUR meds against Kelp 100 mg?

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
23Drugs
23 Moderate

Ingredients driving the most interactions

Iodine 7

Individual Drug Interactions

The ingredients in Kelp 100 mg interact with 23 drugs. Click any drug to see the details.

1 of the 1 ingredient in Kelp 100 mg interact with drugs. Each result below shows which ingredient is responsible. Iodine

Each ingredient & the kinds of drugs it affects

For each ingredient in Kelp 100 mg 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.

Iodine3 drug types · 7 drugs

Amiodarone (Cordarone)

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

Likelihood Probable Evidence D
Antithyroid Drugs

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

Likelihood Probable Evidence D
Lithium

Combining iodine with lithium might have additive hypothyroid effects.
Lithium can inhibit thyroid function. Several case reports suggest that concomitant use of lithium and potassium iodide can reduce thyroid function in otherwise healthy adults. Monitor thyroid function.

Likelihood Probable Evidence D
Iodine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Kelp 100 mg, from the product label.

Windmill

Web Address
www.windmillvitamins.com
Pharmacist Counseling Corner

Kelp 100 mg by Windmill: Common Questions

Does Kelp 100 mg by Windmill interact with any medications?
Yes. Based on its ingredients, Kelp 100 mg has a known interaction with 23 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Kelp 100 mg 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.
Can I take this if I'm pregnant or breastfeeding?
The safety data advises against kelp during pregnancy because high iodine levels and potential heavy metal contaminants could affect the baby. The same caution applies during breastfeeding, since iodine and contaminants pass into breast milk. Talk with your doctor or pharmacist about whether kelp is appropriate for you.
Does kelp actually help with weight loss or blood sugar?
The evidence supporting kelp for weight management or prediabetes is currently insufficient — meaning we don't have enough reliable clinical data to say whether it works for these purposes. If you're looking at kelp for one of these goals, your doctor or pharmacist can help you weigh the options.
What are the side effects?
In a small clinical trial, a small number of women taking kelp powder (500 mg daily for two weeks) showed elevated thyroid stimulating hormone (TSH), a sign the thyroid was reacting to the iodine dose. Kelp is generally used safely in foods, but its iodine content and possible contamination from the seaweed warrant caution if you're taking it as a supplement.
Is kelp safe to take daily?
Kelp from food sources is generally well tolerated, but the daily supplement dose carries more iodine than you'd get from eating seaweed occasionally. If you have a thyroid condition or take thyroid or heart medications, talk with your doctor or pharmacist before taking it regularly.
What exactly is kelp?
Kelp is a brown seaweed (Ascophyllum nodosum) that naturally contains iodine. It's commonly eaten as food in some cuisines and is also sold as a supplement for its iodine content and other micronutrients.
Why does this product say to avoid it during pregnancy if it's just iodine?
Iodine is essential in pregnancy, but kelp delivers it in high doses alongside potential heavy metal contaminants from ocean water. The safety data advises against this form specifically during pregnancy and breastfeeding — your doctor or pharmacist can discuss safer sources of iodine if you need it.

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

Not sure if Kelp 100 mg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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 100 mg label
Go deeper

The Full Monographs Behind Kelp 100 mg’s Ingredients

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

Herb & supplement monograph

Iodine

Interacts with 7 drugs

Iodine is an essential mineral your body needs to make thyroid hormones, and most people get enough from iodized salt, dairy, and seafood. Supplements help when you are truly deficient, but...

Read the full Iodine monograph → Herb & supplement monograph

Ascophyllum Nodosum

Interacts with 22 drugs

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 f...

Read the full Ascophyllum Nodosum monograph →
Sources

Sources & How We Checked

Kelp 100 mg'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 31 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.

Iodine 26 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Goodman GA, Rall TW, Nies AS, Taylor P. The Pharmacological Basis of Therapeutics, 9th ed.
  3. Ghent WR, Eskin BA, Low DA, Hill LP. Iodine replacement in fibrocystic disease of the breast. Can J Surg 1993;36:453-60.
  4. Potassium iodide for nuclear exposure. Pharmacist's Letter/Prescriber's Letter 2001;17(12):171214.
  5. 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.
  6. Cabezas C, Bustamante B, Holgado W, Begue RE. Treatment of cutaneous sporotrichosis with one daily dose of potassium iodide. Pediatr Infect Dis J 1996;15:352-4. PubMed
  7. 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
  8. Yarrington CD, Pearce EN. Dietary iodine in pregnancy and postpartum. Clin Obstet Gynecol 2011;54:459-70. PubMed
  9. Goel, S., Mandhani, A., Srivastava, A., Kapoor, R., Gogoi, S., Kumar, A., and Bhandari, M. Is povidone iodine an alternative to silver nitrate for renal pelvic instillation sclerotherapy in chyluria? BJU.Int 2004;94(7):1082-1085. PubMed
  10. Teng, W., Shan, Z., Teng, X., Guan, H., Li, Y., Teng, D., Jin, Y., Yu, X., Fan, C., Chong, W., Yang, F., Dai, H., Yu, Y., Li, J., Chen, Y., Zhao, D., Shi, X., Hu, F., Mao, J., Gu, X., Yang, R., Tong, Y., Wang, W., Gao, T., and Li, C. Effect of iodine int
  11. Crawford, B. A., Cowell, C. T., Emder, P. J., Learoyd, D. L., Chua, E. L., Sinn, J., and Jack, M. M. Iodine toxicity from soy milk and seaweed ingestion is associated with serious thyroid dysfunction. Med J Aust. 10-4-2010;193(7):413-415. PubMed
  12. Ohkuma, M. Molluscum contagiosum treated with iodine solution and salicylic acid plaster. Int J Dermatol. 1990;29(6):443-445. PubMed
  13. Connelly KJ, Boston BA, Pearce EN, Sesser D, Snyder D, Braverman LE, Pino S, LaFranchi SH. Congenital hypothyroidism caused by excess prenatal maternal iodine ingestion. J Pediatr. 2012 Oct;161(4):760-2. PubMed
  14. Kasahara T, Narumi S, Okasora K, Takaya R, Tamai H, Hasegawa T. Delayed onset congenital hypothyroidism in a patient with DUOX2 mutations and maternal iodine excess. Am J Med Genet A. 2013 Jan;161A(1):214-7.
  15. Murcia M, Rebagliato M, Iñiguez C, Lopez-Espinosa MJ, Estarlich M, Plaza B, Barona-Vilar C, Espada M, Vioque J, Ballester F. Effect of iodine supplementation during pregnancy on infant neurodevelopment at 1 year of age. Am J Epidemiol. 2011 Apr 1;173(7):8 PubMed
  16. Sang Z, Wang PP, Yao Z, Shen J, Halfyard B, Tan L, Zhao N, Wu Y, Gao S, Tan J, Liu J, Chen Z, Zhang W. Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial. Am J Clin Nutr. 2012 Feb;95(2):367-73 PubMed
  17. Speeckaert MM, Speeckaert R, Wierckx K, Delanghe JR, Kaufman JM. Value and pitfalls in iodine fortification and supplementation in the 21st century. Br J Nutr. 2011 Oct;106(7):964-73. PubMed
  18. Yun SE, Kang Y, Bae EJ, Hwang K, Jang HN, Cho HS, Chang SH, Park DJ. Iodine-induced thyrotoxic hypokalemic paralysis after ingestion of Salicornia herbace. Ren Fail. 2014 Apr;36(3):461-3.
  19. Iodine Hypersensitivity. Pharmacist's Letter/Prescriber's Letter 2011; 27(5):270504.
  20. Hammel JA, Selby JC. Pustular eruption in a patient with cancer treated with complementary and alternative medicine. JAMA Dermatology 2017 October; E1. doi: 10.1001/jamadermatol.2017.3749. [Epub ahead of print] PubMed
  21. Gil GS, Smith BW, Guerra JR, Williams WT. Acute Delirium in a Hypothyroid Patient Precipitated by Iodine Supplements Use. Am J Ther. 2018;25(6):e717-e718. PubMed
  22. Hamby T, Kunnel N, Dallas JS, Wilson DP. Maternal iodine excess: an uncommon cause of acquired neonatal hypothyroidism. J Pediatr Endocrinol Metab. 2018;31(9):1061-1064. PubMed
  23. Censi S, Watutantrige-Fernando S, Groccia G, et al. The Effects of Iodine Supplementation in Pregnancy on Iodine Status, Thyroglobulin Levels and Thyroid Function Parameters: Results from a Randomized Controlled Clinical Trial in a Mild-to-Moderate Iodine
  24. Rovner MS, Wolf BJ, Rubin M, et al. Instillation of 5% Povidone-Iodine Ophthalmic Drops Decreases the Respiratory Rate in Children Undergoing Strabismus Surgery: A Randomized Controlled Trial. J Pediatr Ophthalmol Strabismus. 2019;56(6):378-382. PubMed
  25. Guenezan J, Garcia M, Strasters D, et al. Povidone Iodine Mouthwash, Gargle, and Nasal Spray to Reduce Nasopharyngeal Viral Load in Patients With COVID-19: A Randomized Clinical Trial. JAMA Otolaryngol Head Neck Surg. 2021;147(4):400-401. PubMed
  26. Li F, Wan S, Zhang L, et al. A Meta-Analysis of the Effect of Iodine Excess on the Intellectual Development of Children in Areas with High Iodine Levels in their Drinking Water. Biol Trace Elem Res 2022;200(4):1580-1590. PubMed

See these in context on the Iodine monograph →

Ascophyllum Nodosum 5 references
  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  2. 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

See these in context on the Ascophyllum Nodosum 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

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team