Objective:To observe the sex hormone levels in adolescent male acne patients with normal serum testosterone,and to evaluate the curative effect of antiandrogen therapy.Methods:Totally 40 adolescent male acne patients with normal serum testosterone were evenly randomized into two groups:the treatment group received finasteride plus life-style intervention,and the control group received life-style intervention only.The curative effects were compared between the two groups,and the levels of serum testosterone,dihydrotestosterone (DHT),free testosterone (FT),sex hormone binding globulin (SHBG) ,and estradiol (E2),and the adverse effects were observed before and after treatment.The curative effects in the treatment group were also observed 3 months after drug withdrawal.Another 40 healthy adolescent males served as normal group for comparison of the baseline hormone levels with ance patients.Results:The patients in our group had significantly higher levels of body fat content,E2 (P<0.05),DHT,and FT (P<0.01),and lower level of SHBG(P<0.05) compared with those in the normal control group.The overall effective rate of the treatment group was 90%,which was significantly higher than that of the control group ( 25%,P<0.01); the effective rate of the treatment group was 85% 3 months after drug withdrawal.The levels of DHT (P<0.01) and FT(P<0.05) in the treatment group were significantly decreased and the levels of SHBG was significantly increased (P<0.05) after treatment.There were no severe adverse effects in both groups.Conclusion:The adolescent male acne patients with normal serum testosterone have higher body fat content,DHT,FT,E2 and lower SHBF levels.The therapy using finasteride plus life-style is effective; it can greatly improve the serum level of SHBF and reduce adverse effects,with low recurrent rate after drug withdrawal.