In sports, in exercise, and in training, selenium is a frequently overlooked micronutrient. Selenium’s fundamental importance to human health is not well known. Researchers are beginning to conduct studies of selenium in sports nutrition and skeletal muscle health. Their studies show that selenium and selenoproteins play an important role in maintaining skeletal muscle function. Studies show that selenoproteins delay exercise fatigue and muscle aging [Wang 2025].
Optimal selenium intake from food and from supplements (when necessary) can mitigate aging-related muscle decline. Selenium can help to prevent exercise-associated musculoskeletal injuries. There is a need for more clinical studies of the effect of selenium supplementation on skeletal muscle health in selenium-poor regions [Wang 2025].
In particular, we need the following types of studies [Wang 2025]:
- randomized controlled trials of the effect of selenium supplementation on skeletal muscle
- dose–response studies of selenium’s effect on skeletal muscle
- studies of the effects of different species of selenium on skeletal muscle
Selenium Nutrition and Physical Performance
Wang et al have done a systematic review of journal literature relating to selenium nutrition and athletic performance. Basically, the researchers found that selenium does its work in skeletal muscle in three distinct three ways [Wang 2025]:
- by regulating selenoprotein biosynthesis
- by providing antioxidant protection against oxidative stress
- by modulating cellular redox-sensitive signaling pathways
Selenium Supplements: Form and Dose
Form of Selenium Supplement
The absorption of selenium from organic selenium supplements, e.g., 100% selenomethionine supplements and selenium-enriched yeast supplements, is better than the absorption from inorganic selenium supplements, e.g., sodium selenite.
Selenium-enriched yeast supplements contain several other selenium species in addition to their selenomethionine content. Supplements containing 100% selenomethionine do not contain these additional selenium species. It is precisely these other selenium species that may have biological effects not supplied by selenomethionine. For example, in a 2014 randomized clinical study, Richie et al have shown that selenium-enriched yeast supplements significantly reduce the level of oxidative stress in healthy men. Supplements containing 100% selenomethionine did not have the same antioxidant effect [Richie 2014].
Dose of Selenium Supplement
In 2014, the European Food Safety Authority (EFSA) set the adequate intake level of selenium for adults at 70 mcg/day. Then, in 2023, EFSA established a tolerable upper intake level of 255 mcg/day.
For individuals who have the opportunity to have their serum selenium status measured: achieving a serum selenium status of 120-130 mcg/L is necessary to optimize the concentration of selenoprotein P. Selenoprotein P is the major transporter of selenium in the blood. To reach and maintain the 120-130 serum selenium range, Larsen et al estimate that the required selenium intake is at least 100 mcg per day [Larsen 2024].
Conclusions: Selenium and Sports Nutrition
Typically, athletes and individuals who work out do not know the importance of selenium for good muscle function.
Wang’s review shows that adequate selenium intake can be important for both endurance and strength training.
Adequate selenium is needed for the growth of muscle and for the recovery of muscle strength following training.
Selenium supplementation may be necessary to achieve a serum selenium status sufficient to facilitate the bio-synthesis of selenoproteins.
Sources
EFSA. Scientific opinion on dietary reference values for selenium. EFSA Journal. 2014;12(10):3846.
EFSA. Scientific opinion on the tolerable upper intake level for selenium. EFSA Journal. 2023;21(1): e07704.
Larsen C et al. Selenium supplementation and placebo are equally effective in improving quality of life in patients with hypothyroidism. Eur Thyroid J. 2024 Jan 1;13(1):e230175.
Richie JP Jr et al. Comparative effects of two different forms of selenium on oxidative stress biomarkers in healthy men: a randomized clinical trial. Cancer Prev Res (Phila). 2014 Aug;7(8):796-804.
Wang Q et al. Selenium and skeletal muscle health in sports nutrition. Nutrients. 2025 May 31;17(11):1902.
The information presented in this review article is not intended as medical advice. It should not be used as such.