Check before you startThis one has documented interactions with medication classes where the consequences are serious. If you take any prescription medicine, run it past a pharmacist before starting.
Evidence strength
94/100Very strong
WEAKLIMITEDMODERATESTRONGVERY STRONG
What the evidence supports: thyroid function and preventing deficiency disorders.
This scores how well-supported the claim above is — not how much benefit you personally would get. A high score on a narrow claim does not extend to everything the product is marketed for.
How long to take it
Ongoing if your salt isn't iodized and you eat little dairy or seafood. Especially important in pregnancy.
Who it's actually for
Pregnant and breastfeeding women, people using non-iodized salts, and vegans.
Safe upper limit
Reported
1,100 mcg per day
Both too little and too much cause thyroid dysfunction. Kelp products can deliver wildly variable, sometimes enormous doses.