What it is used for
- Treating and preventing selenium deficiency
- Supporting antioxidant defences and thyroid function when intake is low
- Supporting people in regions or diets low in selenium, under guidance
How it works
Selenium is a trace mineral that the body uses in antioxidant enzymes and in processing thyroid hormones. Adequate selenium supports the immune system, thyroid and protection of cells from damage; supplementing corrects deficiency.
How it is taken
Available as tablets, capsules and within some multivitamins, in forms such as selenomethionine or sodium selenite. It can be taken with or without food. Take it exactly as the label or your clinician or pharmacist directs, and avoid high doses, as the safe range is narrow.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Usually well tolerated at recommended amounts
- Mild stomach upset (uncommon)
- Garlic-like breath or metallic taste with higher intake
Serious effects — get help
- Signs of selenium excess (selenosis): hair or nail loss or brittleness, nausea, irritability, nerve problems
- Signs of an allergic reaction (rare)
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Other supplements that also contain selenium, which can add up
- Some medicines and minerals; check with your pharmacist if taking several supplements
Who should take care
- The gap between helpful and harmful amounts is small, so do not exceed recommended doses
- Tell your clinician about all supplements to avoid taking too much selenium
- Discuss use in pregnancy and breastfeeding with your clinician
- Avoid combining several products that all contain selenium