Typical dose
As a dietary supplement: typically 150-600 mcg i...
Oral
Oral safety: low
About this supplement
Kelp is a type of large, brown seaweed (macroalgae) belonging to the order Laminariales. It grows in underwater forests in nutrient-rich, cold coastal waters. Kelp is a rich natural source of iodine, essential minerals (including potassium, magnesium, calcium, and iron), vitamins, antioxidants (like fucoxanthin), and dietary fibers such as alginates. It is commonly consumed as a food (e.g., in sushi, salads, soups) and used as a dietary supplement, primarily for its iodine content which supports thyroid hormone production. It may also have topical applications in beauty products for its mineral and moisturizing properties.
How much to take
- Typical amount
- As a dietary supplement: typically 150-600 mcg iodine daily from kelp (varies greatly by product; must check label). As a food: consumed in variable amounts (e.g., a few grams of dried kelp). Topical use: formulations vary (e.g., 1-5% in creams/masks).
- Suggested range
- Iodine from kelp: 150-300 mcg daily for adults (aligns with RDA). Upper limit for iodine is 1100 mcg/day. Dosage must be carefully monitored due to variable iodine content in kelp.
Potential benefits
Benefits linked to this supplement form:
Things to watch for
Possible side effects linked to this form:
Health goals
Needs and goals this form may help with:
Other forms of Iodine
Compare absorption and active amounts with sibling forms:
Molecular Iodine (I2)
Powerful antiseptic; essential mineral for thyroid function.
Nascent Iodine
A supplemental form of iodine claimed to be in a highly bioavailable atomic stat...
Potassium Iodide
Essential mineral for thyroid function. Also used for thyroid protection in radi...
Sodium Iodide
Essential mineral for thyroid function and metabolism.
Technical details â–¼
Chemical ID (CAS)
92128-82-0 (for kelp extract, approximate); varies by specific compound
Physical properties
Typically dried and sold as dark green to brown flakes, powder, or whole leaves. Soluble dietary fibers (alginates) form viscous gels in water. Contains a complex mixture of polysaccharides, minerals, and pigments.
How it’s made
Wild-harvested or farmed in ocean waters. Processed by washing, drying (sun or oven drying), and often milled into powder or cut into pieces. May be extracted for specific compounds (e.g., alginates, fucoxanthin).