Does Casein Lower Testosterone?

The estrogen-treated rats fed on 20.0% casein diet showed decreased spermatogenesis in comparison with control rats fed on 20.0% casein diet. Together, these results indicate that high casein diet stimulates synthesis of testicular testosterone and increases serum LH levels more than FSH in estrogen-treated rats.

Can protein powder lower testosterone?

This investigation shows that 12 weeks supplementation with soy and whey protein does not decrease serum testosterone or inhibit lean body mass changes in subjects engaged in a resistance exercise program. In this study, testosterone also did not affected by protein supplementation.

What protein is bad for testosterone?

1. Soy and soy-based products. Some research shows that regularly eating soy products like edamame, tofu, soy milk, and miso may cause a drop in testosterone levels. For example, one study in 35 men found that drinking soy protein isolate for 54 days resulted in decreased testosterone levels ( 3 ).