Just a general answer about prohormones, not just 1-test.
Anytime you take something that increases TEST....you have the possibility of it breaking down into Estrogens and DHT.
DHT can cause problems with the prostrate and hairline, Estrogens, with skin and chest tissue,
The addtional Test itself can cause testicular shrinkage.
Biggest problem here (mentioned in my Main Site Article tomorrow) is, that while we rarely see problems with Prohormones, exogenous replacement of Testosterone can lead to suppression "or more" of endogenous production in some individuals. In effect, you are changing your Natural "Hormonal Cascade"