Effects of sex steroid deprivation/administration on hair growth and skin sebum production in transsexual males and females

To investigate androgen effects on the skin pilosebaceous unit, we studied 21 male-to-female transsexuals and 17 female-to-male transsexuals receiving cross-sex hormones. At baseline and after 4, 8, and 12 months, hair growth was evaluated by the Ferriman-Gallwey score; acne by the Leeds classificat ion; hair growth rate, density, and shaft diameter by image analysis; and s ebum production by Sebutape. In males, estrogens and antiandrogens reduced plasma testosterone to below 1.0 nmoL/L. Though all parameters of hair grow th and sebum production declined, facial hair growth continued. After 4 mon ths, the decrease in shaft diameter had reached its maximum and seemed inve rsely associated with changes in hair growth length and density. In females , testosterone increased hair growth rate and sebum production. After 12 mo nths, hairs on the cheek and abdomen had not yet reached diameters found in males. 5 alpha -Androstane-3 alpha ,17 beta -diol glucuronide levels were only weakly associated with hair growth and sebum production. In conclusion , administration of estrogens and antiandrogens affects length and diameter of hairs at different rates. In the virtual absence of androgens, hair gro wth continues but at a slower rate. In women, after 12 months of androgen a dministration, hair diameters have not reached values of adult men.