Does anybody even know what androstenedione is for?

Steroid precursor. Androstenedione is a precursor to naturally occurring steroid (testosterone). The rationale behind using it as a supplement is that if you provide your body with more of the precursor or the desired stuff, then your body will make more of the desired stuff. Studies have not shown that andro supplementation increases testosterone or increases strength. It may increase the female hormone, estradiol.