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

Norwegian Kelp Ingredients & Drug Interactions

by Herbal Select

Norwegian Kelp label
See full label image
Capsule Category: 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 Norwegian 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

Norwegian Kelp is a dietary supplement by Herbal Select with 1 active ingredient. Its ingredients are commonly taken for weight management, blood sugar support, thyroid support (iodine source).Based on those ingredients, 22 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Norwegian Kelp. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Norwegian Kelp by Herbal Select

Ask about any prescription or over-the-counter medication and we check it for interactions with Norwegian Kelp by Herbal Select — 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 Norwegian Kelp by Herbal Select

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 12, 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.

Herbal Select Norwegian Kelp is a single-ingredient supplement: the kelp itself (Ascophyllum nodosum), which is a type of brown seaweed. It's commonly eaten in foods and is naturally rich in iodine.

The capsule also contains gelatin and water as inactive ingredients.

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 Ascophyllum Nodosum product and its label doesn't state a use — see Ascophyllum Nodosum'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 for Norwegian kelp isn't established in our data. We hold insufficient reliable evidence to rate it for prediabetes (impaired glucose tolerance), weight management, GERD (acid reflux), iodine deficiency, or inflammatory bowel disease.

If you're considering it for one of these uses, talk with your pharmacist about what the clinical evidence actually supports.

The evidence, ingredient by ingredient 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.

Norwegian kelp is generally used in food, but its high iodine content and possible heavy metal contamination from seawater warrant caution. In a small clinical trial, one dose of 500 mg daily for 14 days raised thyroid-stimulating hormone (TSH) levels in a small number of participants, though levels of the main thyroid hormone remained stable.

During pregnancy and lactation, the safety data advises against it. Iodine and contaminants can pass into breast milk and may affect the baby's thyroid development, so avoid use if you're pregnant or breastfeeding.

Side effects, ingredient by ingredient 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.

Check your medications against this product if you take antithyroid drugs, thyroid hormone replacements (like levothyroxine), or amiodarone (Cordarone). All three have Moderate interactions with kelp's iodine content that may alter how well they work or shift your iodine levels.

Use the tool below to run your exact medications.

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.

Norwegian Kelp is worth a second look if you take thyroid medications, heart medications like amiodarone, or antithyroid drugs—check your specific prescriptions first. It's generally used in foods, but as a concentrated supplement, the iodine load is higher and comes with a small risk of thyroid effects.

If you're pregnant or breastfeeding, skip it. Talk to your pharmacist before starting.

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 Feb 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 Norwegian Kelp, straight from the product label.

Brand Herbal Select
Barcode (UPC) 065279030349
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Feb 25, 2013
DSLD ID 17674
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Dairy Free, 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 Norwegian Kelp by Herbal Select, 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:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
UPC/BARCODE
065279030349
IngredientAmount% DV
Norwegian Kelp550 mg--

Other ingredients: Gelatin, Water

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

Potent-Max Traditional herb Herbal Select Potent-Max traditional herbs use potent ingredients in effective proportions, so you get consistent results every time.

ZIN: 100689

550 mg

Suggested/Recommended/Usage/Directions

Directions: Take 2 capsules 2 times daily with water.

Formulation

Contains no artificial preservatives, colour, flavour, sugar, starch, wheat, dairy or yeast.

Precautions

Do not use if seal is broken.

FDA Statement of Identity

A Dietary Supplement

FDA Disclaimer Statement

Statements not evaluated by FDA. Product not intended to diagnose, treat, cure, or prevent any disease.

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

See for yourself

Norwegian Kelp by Herbal Select label

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

Norwegian 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 Norwegian Kelp by Herbal Select

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

Serving size2 Capsule(s) Dosage formCapsule Amounts shown are per serving.

Norwegian Kelp

Interacts with
22 drugs
550 mg per serving

Ascophyllum nodosum (often sold as bladderwrack or brown seaweed) is a nutrient-rich algae that people use for weight, blood sugar, and thyroid suppor...

Norwegian Kelp monograph & interactions

Other (inactive) ingredients: Gelatin, Water. These complete the product’s ingredient list but are not active constituents.

Interaction report

Norwegian Kelp by Herbal Select Drug Interactions

Want to check YOUR meds against Norwegian 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
22Drugs
22 Moderate

Ingredients driving the most interactions

Norwegian Kelp 22

Individual Drug Interactions

The ingredients in Norwegian Kelp interact with 22 drugs. Click any drug to see the details.

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

Each ingredient & the kinds of drugs it affects

For each ingredient in Norwegian 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.

Norwegian Kelp3 drug types · 22 drugs

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
Norwegian Kelp full monograph & interactions
The maker

Brand information

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

Herbal Select

See all Herbal Select products
Name
Herbal Select
Street Address
Unit 2-355 Michener Rd.
City
Guelph
State
Ontario
ZipCode
N1K 1E8
Phone Number
1-888-313-3369
Web Address
www.herbalselect.com
Pharmacist Counseling Corner

Norwegian Kelp by Herbal Select: Common Questions

Does Norwegian Kelp by Herbal Select interact with any medications?
Yes. Based on its ingredients, Norwegian Kelp has a known interaction with 22 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Norwegian Kelp 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.
Will Norwegian Kelp help with weight loss or blood sugar?
We don't have reliable evidence that it works for either. The evidence for prediabetes and obesity is insufficient to rate, so we can't tell you whether it's effective for those uses.
Can I take this while pregnant or breastfeeding?
No—the safety data advises against it. Kelp's high iodine content and possible contaminants can pass into breast milk and may harm the baby's thyroid development. Talk with your doctor or midwife about safer options.
Does Norwegian Kelp have side effects?
In a small trial, one dose of the supplement raised thyroid hormone markers (TSH) in a couple of participants, though other thyroid measures stayed normal. The supplement is used in food, but as a concentrate it carries more iodine, so thyroid effects are possible.
What's the kelp actually used for?
Historically, kelp is a source of iodine, which your thyroid needs. But we don't have solid evidence that this supplement helps with iodine deficiency or any other condition listed in our data.
Is Norwegian Kelp just a filler product?
It's a single active ingredient—the kelp itself—plus gelatin and water to make the capsule. You're getting kelp as the supplement; there are no other actives inside.

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

Not sure if Norwegian Kelp 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.

Norwegian Kelp label
Go deeper

The Full Monographs Behind Norwegian Kelp’s Ingredients

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

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

Norwegian 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 5 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.

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