What is it used for?
All products
Source of antioxidants/Provides antioxidants [Source note 2].
Source of antioxidants/Provides antioxidants that help fight/protect (cell) against/reduce (the oxidative effect of/the oxidative damage caused by/cell damage caused by) free radicals [Source note 3].
Products providing 0.8 g or more of Fucus vesiculosus per day
(Traditionally) used in Herbal Medicine as an alterative for the glandular system (Hoffman 2003; Duke 2002; Grieve 1931a,b; Felter and Lloyd 1898).
Used in Herbal Medicine to support normal thyroid function (Bradley 1992; Grieve 1931a,b; Ellingwood 1919).
Products standardized to iodine
As per the source authority Multi-vitamin/mineral Supplements reference.
For multi-ingredient products:
To prevent the product from being represented as a "traditional medicine", any indicated traditional use claim must refer to the specific active ingredient(s) and recognized system of medicine from which the claim originates when 1) both traditional and modern claims are present or 2) when claims originate from multiple systems of traditional medicine (e.g., Kelp is traditionally used in Herbal Medicine as an alterative for the glandular system).
When ALL of the active ingredients (MIs) in the product are used within the SAME identified system of traditional medicine AND the product makes ONLY traditional claims, listing of MIs in the traditional claim(s) is not required.
Who does this guide cover?
Adults 18 years and older
How is it taken?
Oral
Which forms are covered?
this reference excludes foods or food-like dosage forms as indicated in the Compendium of references Guidance Document.
Quantities
Antioxidants
Methods of preparation: Dry, Powdered, Non-standardized ethanolic extracts (Dry extract, Tincture, Fluid extract)
Not to exceed 1 gram of kelp per day [Source note 4].
Fucus vesiculosus: alterative, support normal thyroid function
Methods of preparation: Dry, Powdered, Non-standardized ethanolic extracts (Dry extract, Tincture, Fluid extract)
0.8 - 1 gram of Fucus vesiculosus per day [Source note 5].
Iodine claims (Multi-vitamin/mineral Supplements reference)
Methods of preparation: Dry standardized, Powdered standardized, Standardized extracts (Dry extract, Tincture, Fluid extract, Decoction, Infusion)
active ingredient(s) must provide the minimum amount of iodine outlined on the current source authority Multi-vitamin/mineral Supplements reference.
Iodine should be indicated on the product documentation form as a potency constituent.
Note: The total amount of iodine provided by the product must not exceed 800 micrograms iodine per day [Source note 6].
How is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
How long is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Warnings and precautions
All products
Ask a healthcare professional before use if you are taking blood thinners [Source note 7].
Ask a healthcare professional before use if you are pregnant or breastfeeding [Source note 8].
When should it be avoided?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Possible side effects
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Storage
Must be established in accordance with the requirements described in the applicable product regulations.
Preparation details
Ingredient identity, preparation requirements, and other details that define the scope of this guide.
Ingredients and preparations
| Proper name(s) | Common name(s) | Source information / Source material(s) | Source information / Part(s) | Source information / Preparation(s) |
|---|---|---|---|---|
| Ascophyllum nodosum |
| Ascophyllum nodosum |
| Dry |
| Fucus vesiculosus |
| Fucus vesiculosus |
| Dry |
| Laminaria digitata |
| Laminaria digitata |
| Dry |
| Saccharina japonica |
| Saccharina japonica |
| Dry |
References: Proper name: Guiry and Guiry 2018a,b; Common names: TGA 2020; Source information: Guiry and Guiry 2018a,b.
Other ingredients
Must be chosen from the current source ingredient database and must meet the limitations outlined in the database.
Preparation and quality requirements
The finished product specifications must be established in accordance with the requirements described in the source authority source’s product quality guidance.
The active ingredient must comply with the requirements outlined in the source ingredient database.
Guide change history
Updates to this SupplementSafety.org guide.
Minor updates
Updated guide wording, organization, and source presentation. Added our editorial change history.
Initial release
Initial SupplementSafety.org guide prepared from source reference material.
Validation: Not yet completed. Editorial updates do not constitute clinical validation.
Sources
Source information
This guide organizes source material about uses, preparations, amounts, and precautions. Read the conditions alongside each statement; the information may apply only to particular preparations or populations.
The source document includes supporting references. We have not independently summarized or assessed every cited study for this guide.
- Source document version
- May 29, 2026
- Source captured
- Aug 15, 2026
- Editorial work
- Editorial preparation. Independent clinical review has not been recorded for this guide.
Full citations are available through the link above. Verification is required to open them; reading this guide does not require verification.
Taking a medication too?
Explore our supplement–medication interaction checker. Its coverage and review status are shown with the results; a missing finding does not establish that a combination is safe.