Best for Longevity
Best Selenium for Longevity
Top 28 products ranked · Reviewed May 2026 · 100–200 mcg clinical dose
Why Selenium for Longevity
Selenium plays a supporting role in longevity. Essential component of selenoproteins including glutathione peroxidase (antioxidant defense) and deiodinases (thyroid hormone activation). Selenomethionine is the most bioavailable supplemental form, while sodium selenite is inorganic and less efficiently absorbed.
What dose to look for
Clinical studies typically use 100–200 mcg of selenium. Common supplement dose; UL is 400 mcg/day. Products below this range may not deliver meaningful results.
What form to look for
Avoid sodium selenite — inorganic, lower retention. Look for selenomethionine for better absorption.
What the research says
Selenium has moderate clinical evidence for longevity benefits. SELECT (n=35,533) showed no cancer prevention benefit and an INCREASE in type 2 diabetes risk. Essential thyroid cofactor in deficient populations; supplement only when intake is documented low Learn more
Clinical research on Selenium
LOW — landmark RCT null/negative for the cellular thesis; mechanism only for oxidative stress · RDA 55 µg/day covers selenoprotein function; no cellular-aging benefit shown at the 200 µg/day dose used in the cancer-prevention trials (SELECT, NPC). Upper limit 400 µg/day — do not exceed.
- •SELECT (Lippman 2009, JAMA), the largest cancer-prevention RCT ever run for selenium — 35,533 healthy men on 200 µg/day L-selenomethionine — found no reduction in prostate cancer and was halted early for futility. This is the most rigorous test of the oxidative-DNA-damage rationale that underpins any cellular/longevity claim, and it was null in an already selenium-replete population. PubMed
- •The Stranges 2007 secondary analysis of the Nutritional Prevention of Cancer trial (NPC, 200 µg/day selenium-enriched yeast) found increased incident type 2 diabetes in the selenium arm, concentrated in participants with the highest baseline selenium. For a cellular-metabolic-health framing the supplementation signal points toward harm, not benefit, and matches later observational U-shaped curves.
- •Mechanistically, selenium is the cofactor for glutathione peroxidases and thioredoxin reductases that neutralize lipid hydroperoxides and regenerate antioxidant systems — settled biochemistry at the RDA level. But this antioxidant role has produced no human trials on mitochondrial function, NAD+ metabolism, cellular senescence, or longevity endpoints; moving from replete to supraphysiological status has not been shown to slow cellular aging.