Up until now, all/most male birth control pills have centered around exogenous testosterone + progesterone/something else. Ignoring the other compound, exogenou

Up until now, all/most male birth control pills have centered around exogenous testosterone + progesterone/something else. Ignoring the other compound, exogenous testosterone supplementation would lead to all sorts of potential abuse since it's an anabolic steroid. There's also the fact that any oral formulation of testosterone (see dianabol for example) is extremely toxic on the liver, and leads to much higher levels of estradiol (which has its own side effects) due to homeostasis. The secondary compounds also have their own significant side effects, to the point where it really makes me wonder how bad hormonal birth control can be for women. So this compound blocking vitamin A is a pretty novel approach.