Selenium is an essential trace mineral that plays a central role in the body's antioxidant defense systems, primarily through its incorporation into selenoproteins such as glutathione peroxidase and thioredoxin reductase. Research suggests that adequate selenium status supports healthy immune function, thyroid hormone metabolism, and reproductive health in both men and women. Studies indicate that selenium may also play a role in cognitive health and has been widely investigated for its potential association with reduced oxidative stress and lower risk of certain cancers, though findings in this area remain mixed and are still evolving. Commonly available as selenomethionine, sodium selenite, or selenium yeast, this mineral is found naturally in Brazil nuts, seafood, and organ meats, with soil selenium content significantly influencing levels in plant-based foods.
Compare this supplementResearch suggests that higher selenium status is associated with better cognitive performance across several observat...
View studies →Research suggests that selenium's relationship with cancer risk is complex and highly dependent on baseline selenium ...
View studies →Research suggests that selenium plays a meaningful role in supporting immune function, with multiple reviews indicati...
View studies →Research suggests that selenium plays a meaningful role in thyroid health, particularly through its involvement in th...
View studies →Research suggests that selenium plays a meaningful role in antioxidant defense through its incorporation into a class...
View studies →The two studies provided do not directly investigate selenium or its effects on fertility. Both studies examine unrel...
View studies →Selenium and vitamin E work together as complementary antioxidants.
View details →Selenium is essential for thyroid hormone metabolism and works synergistically with iodine.
View details →These are commonly referenced dosage ranges for this supplement. They are not medical recommendations. Always consult a healthcare provider before supplementing.
| Form | Dose range | Frequency | Studied for | Source |
|---|---|---|---|---|
| Tablet | 100–200 mcg | Daily | Antioxidant support and immune function | Common range in clinical trials including Nutritional Prevention of Cancer (NPC) trial |
| Tablet | 200 mcg | Daily | Cancer risk reduction and selenium status optimization | Used in NPC trial and SELECT trial; most frequently studied dose for cancer endpoints |
| Tablet | 100 mcg | Daily | Cognitive function and mood support in elderly populations | Used in trials such as the KiSel-10 study and cognitive aging research |
| Tablet | 55 mcg | Daily | General health and meeting recommended dietary allowance for adults | Based on established RDA; consistent with baseline supplementation trials |
| Tablet | 100–200 mcg | Daily | Male fertility support; improvement in sperm motility and morphology | Based on RCTs examining selenium alone or in combination with other antioxidants |
| Tablet | 100–200 mcg | Daily | Thyroid health, particularly in autoimmune thyroid disease (Hashimoto's thyroiditis) | Based on multiple RCTs showing reduced thyroid peroxidase antibody levels at these doses |