Testosterone and dhe. Acne can be seen in men of all ages due to hormonal fluctuations. Improving the acne is good skin care, improving your diet (eat low glycemic, more fruits and veggies rather than refined foods, decreasing dairy) and the use of peels or lasers depending on how severe it is. You have Accutane as an option but only for severe acne.
Testesterone. Acne in adolescents is caused by increased testosterone production as they enter puberty (both males and females). Ditto for pregnant women. The testosterone causes increased oil production, which overwhelms the oil duct, leading to clogging, and then acne. Other hormones are probably involved as well; the exact hormonal combination has not yet been worked out.