Vitamin E, particularly in the form of alpha-tocopheryl succinate, has some scientific basis for supporting testicular health and function, though evidence is moderate and primarily based on animal studies and limited human data. Vitamin E is a fat-soluble antioxidant, and the testes are highly susceptible to oxidative stress due to their active metabolic processes and high content of polyunsaturated fatty acids. Research, especially in rodents, shows that Vitamin E deficiency can result in testicular degeneration, impaired spermatogenesis, and reduced fertility. Supplementation with Vitamin E in animal models has demonstrated protection against testicular oxidative damage, improved sperm quality, and increased testosterone levels under stress or toxic insult.

In humans, studies are relatively limited but suggest that Vitamin E supplementation may improve semen quality in men with infertility, particularly when used in combination with other antioxidants. Some clinical trials have reported improvements in sperm motility and DNA integrity with Vitamin E, though results are not universally consistent. The primary justification for its use in supporting the testes is thus grounded in its role as an antioxidant and its demonstrated ability to mitigate oxidative stress, which is a known factor in male reproductive dysfunction. However, robust, large-scale clinical trials in humans are lacking, so while there is scientific rationale, the strength of evidence is moderate rather than strong.