Selenium’s role in muscles during exercise

Selenium, a key component of several selenoproteins and antioxidants, plays a crucial role in cellular energy metabolism, overall metabolism, and protection against damage caused by oxidative stress. Because of this, selenium helps delay muscle fatigue during athletic performance, reduce muscle loss, and prevent premature aging of muscles. This is highlighted in a review article published in Nutrients, where researchers summarized the latest findings on the role of different selenium compounds in muscles and optimal sports nutrition.

Selenium is important for overall health. Studies show that this trace element is part of 25-30 different selenoproteins, which are produced as needed through a complex selenium metabolism. These selenoproteins primarily serve as essential enzymes, involved in many biological processes, including energy production in mitochondria, activation of thyroid hormones, and the structure and function of muscles. In addition, several selenoproteins serve as powerful antioxidants, protecting the body from oxidative stress, which is a condition where free radicals outnumber protective antioxidants and attack cells and tissues. We all generate free radicals during oxygen metabolism and other processes, and antioxidants are needed to keep them in check. A selenium deficiency can therefore lead to numerous health issues, including metabolic disorders, infections, cardiovascular problems, reduced fertility, and cancer.

How selenium deficiency can affect muscles

Muscles, which normally make up 30–40% of body weight, serve several functions: facilitating movement, protecting organs from impact, storing proteins, and producing heat.
Since sports and physical activity increase energy demands, they also increase exposure to free radicals. Evidence suggests that muscles are particularly vulnerable to damage caused by selenium deficiency. The review article notes that selenium deficiency is linked to an increased risk of the following muscle issues and dysfunctions:

Impaired muscle contraction
Muscle necrosis and atrophy due to vascular damage
Degeneration
Calcification

It is well known that intense training can damage muscle cells, and selenium deficiency can reduce the muscles’ ability to regenerate and function properly. Because muscle tissue is one of the largest tissues in the body, it’s especially important that muscles can perform physical activities and recover after stress. The review examines the roles of different selenoproteins, summarized here:

Selenoprotein P

Selenoprotein P primarily transports selenium through the blood, after which cells take it up and produce other selenoproteins as needed.

Selenoprotein W

Selenoprotein W is one of the selenium-containing antioxidants. It also plays a role in cell signaling and the growth and development of muscle cells. Mice lacking selenoprotein W show signs of muscle loss.

Selenoprotein N

Selenoprotein N is critical for muscle development and the function of the endoplasmic reticulum (ER), which produces proteins and lipids. A deficiency can impair calcium release, which is essential for muscle contraction, and may lead to fatigue, muscle pain, and loss of muscle mass, including age-related sarcopenia.

Selenoprotein K

Selenoprotein K contributes to ER function, acts as an antioxidant, and supports muscle cell regeneration. It is abundant in muscle tissue. Deficiency can disrupt calcium balance, blood sugar regulation, and make muscle regeneration more difficult.

Selenoprotein S

Selenoprotein S supports ER function and antioxidant activity, and it regulates immune system cytokines, which influence anti-inflammatory processes. Studies show that a lack of selenoprotein S increases oxidative and ER stress and may boost pro-inflammatory cytokines, potentially causing post-exercise inflammation and pain.

GPX 1–5

GPX 1–5 (glutathione peroxidases 1–5) are among the most potent antioxidants and circulate in the blood. GPX1 is especially active in the cytoplasm, preventing lipid peroxidation after exercise - a harmful process where membrane lipids oxidize, triggering chain reactions in the cells. GPX4, located in mitochondria, protects against ferroptosis, an iron-dependent form of cell death. In endurance athletes, GPX levels in muscles can rise by 65% after training to protect against oxidative stress. Conversely, GPX4 deficiency can trigger lipid peroxidation, leading to muscle fiber necrosis.

Thioredoxin reductase (TXnrd 1–3)

TXnrd 1–3 supports mitochondrial energy metabolism, enhances coenzyme Q10’s effect on energy production, and acts as a critical antioxidant, protecting mitochondria from oxidative stress.

MSRB1

MSRB1 (methionine-R-sulfoxide reductase) is found in the cytosol and nucleus and is believed to help regulate and build muscle mass.

Other selenoproteins

Additional selenoproteins, including O, F, and T, contribute to protein formation, muscle function, and protection against oxidative damage. These proteins work together closely to fulfill their roles.

Selenium supplementation and sports performance

As noted, selenium is important for energy metabolism, muscle function, and antioxidant defense, all of which are particularly important during physical activity. Intensive and endurance sports increase energy demands and produce more free radicals, which can raise selenium requirements.
Selenium deficiency is common in many parts of the world due to dietary changes, lower intake of fish and organ meats, and depleted soils that affect the food chain. According to the review, many athletes may benefit from selenium supplementation to support muscle function and speed recovery after intense training.
Official daily selenium recommendations range from 60–90 micrograms, with an upper limit of 255 micrograms in Europe and 400 micrograms in China. Many studies use doses of 100–200 micrograms daily, which also supports selenium’s other functions in metabolism and disease prevention. Selenium yeast with many different organic selenium types has been shown to be most effective.
For optimal results, selenium supplementation can be combined with coenzyme Q10 to enhance energy metabolism and antioxidant defenses, as these nutrients work synergistically. You can read more here:

• Q10’s positive role in exercise, muscle strength, and recovery

References:

Qi Wang et al. Selenium and Skeletal Muscle Health in Sports Nutrition. Nutrients 2025

Zhenwu Bin, Liu Wwi. The role of Q10 in exercise tolerance and muscle strength. Archives of Physiology and Biochemistry. 2025