To assess levels of androgen metabolites thought to reflect, at least in part, peripheral androgen activity in women with androgenic alopecia and men with premature balding in an effort to determine if a common abnormality exists. Prospective study in various groups of women and men. Reproductive Endocrine Clinic at our university medical center. Ten normal ovulatory female controls and 50 hyperandrogenic women divided on the basis of hirsutism and alopecia as follows: [1] 8 hirsute women with androgenic alopecia; [2] 12 nonhirsute women with androgenic alopecia; [3] 18 hirsute women without androgenic alopecia; and [4] 12 nonhirsute women without androgenic alopecia. Ten normal men and 10 young premature balding men matched for age and weight also were compared. Blood was obtained from all subjects. Comparison of blood hormone levels in the various groups. Serum T, androstenedione, and DHEAS were similarly elevated in hyperandrogenic women with and without alopecia, compared with controls. The female groups were then divided on the basis of hirsutism. Hirsute groups with and without alopecia had similarly elevated levels of unconjugated 3 alpha-androstanediol, 3 alpha-androstanediol glucuronide, 3 alpha-androstanediol sulfate, androsterone glucuronide, and androsterone sulfate compared with controls. In the nonhirsute groups, androgenic alopecia patients were compared with hyperandrogenic females and cycling controls. The androgenic alopecia patients had elevated levels of 3 alpha androstanediol (0.75 +/- 0.12 versus 0.46 +/- 0.1 and 0.41 +/- 0.1 nmol/L), 3 alpha-androstanediol sulfate (200 +/- 31 versus 79.6 +/- 6 and 67.0 +/- 4.0 nmol/L), elevated ratios of 3 alpha-androstanediol sulfate:3 alpha-androstanediol (267 +/- 49 versus 170 +/- 20 and 164 +/- 49 nmol/L), elevated ratios of 3 alpha-androstanediol sulfate:3 alpha-androstanediol glucuronide (32.2 +/- 6 versus 10.8 +/- 1 and 10.0 +/- 1) and lower ratios of 3 alpha-androstanediol glucuronide:3 alpha-androstanediol glucuronide (8.3 +/- 1.8 versus 17 +/- 1.7 and 15.2 +/- 1.6 nmol/L). In men the premature balding group had lower levels of 3 alpha-androstanediol glucuronide compared with the male controls (29.8 +/- 4.4 versus 15.2 +/- 1.6 nmol/L). Also, the ratio of 3 alpha-androstanediol glucuronide:3 alpha-androstanediol was significantly decreased, whereas the ratio of 3 alpha-androstanediol sulfate:3 alpha-androstanediol glucuronide was elevated. These data provided evidence confirming that enhanced 5 alpha-reductase activity occurs in androgenic alopecia but also suggests that a disorder of androgen conjugation, favoring sulfurylation over glucuronidation, may be a characteristic feature of scalp hair loss.