Testosterone
There is a Huberman Lab episode with Robert Sapolsky.
Apparently, Sapolsky also wrote a book about it called The Trouble with Testosterone.
Aggression
According to Sapolsky, testosterone does not cause aggression. Rather, it amplifies already existing aggression. Testosterone is also about defending challenges to (social) status, which is why, in humans, the link with aggression is even more tenuous. This is the case because humans have loads of ways to assert, defend and communicate status (e.g. buying expensive stuff).