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Dietary supplement

Irish Moss Ingredients & Drug Interactions

by Herb Stop

Irish Moss label
See full label image
Capsule Category: 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 Irish Moss 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

Irish Moss is a dietary supplement by Herb Stop with 1 active ingredient. Its ingredients are commonly taken for source of iodine and minerals, thyroid support, respiratory issues and cough.Based on those ingredients, 22 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Irish Moss. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Irish Moss by Herb Stop

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

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HelloPharmacist Scorecard of Irish Moss by Herb Stop

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 11, 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 contains one active ingredient: Irish moss, also called sea moss. It's a type of seaweed that's been used traditionally as a source of minerals and iodine.

The capsule is filled with inactive ingredients — hydroxypropyl methylcellulose (the capsule material itself) and purified water.

Does it work?

Not established
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 established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Sea Moss's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: supports healthy thyroid function and mucous membrane health.
  • We looked for evidence on: Iodine deficiency, Hypothyroidism, Respiratory health, Mucous membrane inflammation.
  • The closest evidence on file: Sea Moss is rated "Insufficient Reliable Evidence To Rate" for Iodine deficiency (Natural Medicines).

The evidence we hold doesn't establish that Irish moss works for fatigue, muscle strength, chronic pain, quality of life, or iodine deficiency. The ratings across these uses are all insufficient reliable evidence to rate — meaning the data either isn't there or isn't strong enough to draw a conclusion.

The evidence, ingredient by ingredient Sea Moss

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.

Sea moss is generally viewed as a food, but here's the catch: the amount of iodine in it can vary widely, and it may pick up heavy metals from seawater. One observational study reported constipation and diarrhea in some people who took it orally.

Because iodine levels are unpredictable and the supplement may contain contaminants, the safety data advises against using it during pregnancy. For breastfeeding, there isn't enough data to know whether it's safe — excess iodine could affect your baby — so talk with your doctor or pharmacist before using it if you're nursing.

Side effects, ingredient by ingredient Sea Moss

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 — Sea Moss.
  • 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 with your pharmacist before using Irish Moss if you take antithyroid drugs, thyroid hormone replacement, or amiodarone (Cordarone). All three interact with sea moss's iodine content at Moderate severity.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

Irish Moss might interest you if you're looking for a seaweed-based mineral supplement, but the evidence for what it actually does is thin. If you take any medication for your thyroid or heart rhythm, you need to check with your pharmacist first — the iodine in sea moss can interfere.

Pregnant people and anyone breastfeeding should avoid 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 Sep 25, 2023.

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 Irish Moss, straight from the product label.

Brand Herb Stop
Net contents 300 Veggie Capsule(s)
Market status On market
Date entered into DSLD Sep 25, 2023
DSLD ID 297335
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Women (not pregnant or lactating), 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 Irish Moss by Herb Stop, 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:
2 Capsule(s)
Servings per container
300
IngredientAmount% DV
Irish Moss573 mg--

Other ingredients: Hydroxypropyl Methylcellulose, Water, Purified

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

Suggested Use: Take 1 to 2 capsules 1 to 3 times per day with with water, or as directed by your qualified healthcare professional.

Precautions

Safety Guideline: Not to be used during pregnancy or lactation. If you have a medical condition or take pharmaceutical drugs, please consult with your doctor before use.

Keep away from children.

Use only as directed on label.

Brand IP Statement(s)

Herb Stop Health in your own hands

Formulation

Herbal Capsule

Supports healthy thyroid function Soothes dry & inflamed mucous membranes

Vegan & Cruelty-Free

Vegan & Cruelty-Free

FDA Statement of Identity

Dietary Supplement

FDA Disclaimer Statement

These statements have not been evaluated by the FDA. This product is 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

Irish Moss by Herb Stop label

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

Irish Moss 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 Irish Moss by Herb Stop

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container300 Amounts shown are per serving.

Irish Moss

Interacts with
22 drugs
573 mg per serving

Sea moss is a type of red seaweed that is naturally rich in iodine and several minerals, and it is popular as a 'whole-food' supplement. Strong human...

Irish Moss monograph & interactions

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

Interaction report

Irish Moss by Herb Stop Drug Interactions

Want to check YOUR meds against Irish Moss?

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

Irish Moss 22

Individual Drug Interactions

The ingredients in Irish Moss interact with 22 drugs. Click any drug to see the details.

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

Each ingredient & the kinds of drugs it affects

For each ingredient in Irish Moss 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.

Irish Moss3 drug types · 22 drugs

Amiodarone (Cordarone)

Theoretically, combining sea moss with amiodarone might cause excessively high iodine levels.
Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use with sea moss, which contains approximately 4-7 mcg of iodine per gram, might increase the risk of adverse effects from iodine, including altered thyroid function.

Likelihood Possible Evidence D
Antithyroid Drugs

Due to its iodine content, sea moss might alter the effects of antithyroid drugs.
Sea moss contains approximately 4-7 mcg of iodine per gram. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking sea moss could theoretically alter the effects of antithyroid drugs.

Likelihood Possible Evidence D
Thyroid Hormone

Due to its iodine content, sea moss might alter the effects of thyroid hormone.
Sea moss contains approximately 4-7 mcg of iodine per gram. Iodine in high doses has been reported to cause both hyperthyroidism and hypothyroidism, depending on the individual's past medical history. Taking sea moss could theoretically alter the effects of thyroid hormone.

Likelihood Possible Evidence D
Irish Moss full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Irish Moss, from the product label.

Herb Stop

See all Herb Stop products
Name
The Herb Stop
Street Address
PO Box 673
City
Pine
State
AZ
ZipCode
85544
Phone Number
877.345.4372
Web Address
www.herbstop.com
Pharmacist Counseling Corner

Irish Moss by Herb Stop: Common Questions

Does Irish Moss by Herb Stop interact with any medications?
Yes. Based on its ingredients, Irish Moss 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?
Irish Moss 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 Irish Moss if I'm pregnant or breastfeeding?
The safety data advises against it during pregnancy because iodine levels are unpredictable and heavy metals could be present. If you're breastfeeding, there isn't enough data to know either way — excess iodine might affect your baby. Talk with your doctor or pharmacist for personalized advice.
What side effects has Irish Moss been reported to cause?
In one observational study, people reported constipation and diarrhea after taking it orally. That's the only adverse effect documented in the data we hold.
Does Irish Moss really help with fatigue or muscle strength?
The evidence isn't established. Our data rates fatigue, muscle strength, chronic pain, and quality of life all as insufficient reliable evidence to rate — meaning we don't have strong enough information to say whether it works for any of these.
Why does iodine content matter so much with this supplement?
Sea moss contains 4–7 mcg of iodine per gram, and iodine in high doses can affect your thyroid function — it can cause both an overactive and underactive thyroid depending on your health history. That's why it can interfere with thyroid and heart medications.
What makes Irish Moss risky even as a 'food'?
The amount of iodine varies unpredictably from batch to batch, and seaweed can absorb heavy metals from seawater. Those two things — variable iodine and possible contaminants — are why caution is warranted even though sea moss is generally viewed as a food.

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.

Irish Moss label
Go deeper

The Full Monographs Behind Irish Moss’s Ingredients

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

Herb & supplement monograph

Sea Moss

Interacts with 22 drugs

Sea moss is a type of red seaweed that is naturally rich in iodine and several minerals, and it is popular as a 'whole-food' supplement. Strong human evidence for most of its health claims i...

Read the full Sea Moss monograph →
Sources

Sources & How We Checked

Irish Moss'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 3 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.

Sea Moss 3 references
  1. Darias-Rosales J, Rubio C, Gutiérrez ÁJ, Paz S, Hardisson A. Risk assessment of iodine intake from the consumption of red seaweeds (Palmaria palmata and Chondrus crispus). Environ Sci Pollut Res Int 2020;27(36):45737-45741. PubMed
  2. U.S. Department of Agriculture (USDA). Agricultural Research Service. FoodData Central. Seaweed, irishmoss, raw. April 2019. Available at: https://fdc.nal.usda.gov/fdc-app.html#/food-details/168456/nutrients. Accessed Aug. 30, 2022.
  3. Palmieri B, Vadalà M, Laurino C. Clinical effects of overwintered-stressed Chondrus Crispus and non-overwintered-stressed Chondrus crispus dietary supplementations. Asian J Med Sci. 2018; 9(6): 7-13. DOI

See these in context on the Sea Moss 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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