Vitamin E, commonly in the form of tocopheryl acetate, has a scientific basis for its use in supporting the testes and male reproductive health, though the strength of evidence is moderate. As a fat-soluble antioxidant, Vitamin E protects cell membranes from oxidative damage, which is particularly relevant in the testes, where high rates of cell division and metabolic activity make sperm cells vulnerable to oxidative stress. Several animal studies and some human clinical trials have investigated the role of Vitamin E in male fertility. Results suggest that Vitamin E supplementation can improve sperm motility and reduce DNA damage in sperm, likely due to its antioxidant properties.

For example, a meta-analysis of randomized controlled trials has shown a modest improvement in sperm quality and pregnancy rates in subfertile men taking Vitamin E, especially when combined with other antioxidants. However, the effects are not universally observed, and some studies have found no significant benefit. The majority of supportive evidence comes from studies in men with existing fertility issues or oxidative stress, rather than healthy men. There is less evidence to suggest that Vitamin E enhances testicular function or testosterone production in healthy individuals.

In summary, while Vitamin E is not a miracle supplement for male reproductive health, there is a reasonable, science-based rationale for its use in addressing oxidative stress-related infertility, particularly in combination with other antioxidants. The evidence is moderate (3/5) and strongest in cases of subfertility or increased oxidative stress.