Selenium 200 mcg by NOW

If you’re targeting thyroid health, selenium 200 mcg fits adults with autoimmune thyroid markers, especially Thyroid Peroxidase Antibodies (TPOAb, the immune attack on the thyroid). It’s also reasonable if your Selenium blood level is low, you avoid seafood and eggs, live in low-selenium soil regions, or have malabsorption (celiac, inflammatory bowel disease, bariatric surgery) or are on dialysis. For routine maintenance when your Selenium level is adequate, 50–100 mcg is often enough; 200 mcg is a purposeful dose used in thyroid antibody trials.

L‑selenomethionine (the form here) is absorbed well and gets stored in place of methionine inside body proteins, creating a steady selenium reserve. Your cells use selenium to build selenoproteins, including glutathione peroxidases (antioxidant enzymes that neutralize peroxides) and deiodinases (the enzymes that convert T4 into active T3). In Hashimoto’s, trials show 200 mcg can lower TPOAb and modestly improve well‑being over 3–6 months, likely by reducing oxidative stress in the thyroid. Effects on general immunity or inflammation markers like hs‑CRP are small and inconsistent.

Take one capsule daily with a meal, ideally at the same time each day. If you use levothyroxine for thyroid replacement, separate selenium by at least 4 hours to keep dosing consistent. Re‑check your Selenium level, TSH (the pituitary signal for thyroid output), Free T4, Free T3, and TPOAb after 12–24 weeks. If your level was low, you can often step down to 50–100 mcg for maintenance once repleted.

If you already take a multivitamin plus Brazil nuts or other selenium products, add up your total—too much selenium can cause hair loss, brittle nails, and a garlic breath odor. High lifelong intakes have been linked to higher blood sugar risk in some studies, so avoid extra selenium if your Selenium level is high. Pregnancy: stay within prenatal totals and ask your clinician. Cancer patients on chemotherapy should clear any selenium supplement with their oncologist.

Brazil nuts are rich in selenium but vary wildly by batch; one to two nuts can exceed a full day’s intake. A standardized 200 mcg capsule is easier to control. Expect any thyroid antibody changes in 3–6 months, not weeks. If you’re after hair or nail benefits, they only improve if low selenium was the cause, so check a Selenium blood test first.