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.
How long to take it
Ongoing only in genuinely low-selenium regions. Otherwise unnecessary.
Who it's actually for
People in low-selenium soil areas, and some thyroid conditions under supervision.
Safe upper limit
Unverified400 mcg per day
The gap between adequate and toxic is narrow. Excess causes hair loss, brittle nails, garlic breath, and nerve damage.
No source attached yet. Treat this as a starting point, not a citation, until reviewed.
Interactions to know about
- Thyroid medication — Levothyroxine, carbimazole, methimazole
Other supplements:
Run your full list through the interaction check.
Practical notes
- Two brazil nuts a day can exceed the requirement — don't add a supplement on top.
- This is one where a blood test genuinely matters.