The quantitative changes in body hair growth, and sebaceous secretion, as well as plasma sex hormone binding globulin, luteinizing hormone and follicle stimulating hormone, testosterone and androstenedione were measured in a hirsute woman aged 21 years under ‘reverse sequential’ treatment with cyproterone acetate and ethinyl oestradiol. The subject, before treatment, had normal excretion of 17-oxosteroids, 17-oxogenic steroids, androsterone, dehydroepiandrosterone and aetiocholanolone.

The rate of hair growth on the thigh and the average diameter of the hairs was significantly reduced after only 2 cycles of treatment. After 6–7 cycles the length attained by the terminal hairs was reduced and this appeared to be due mainly to change in growth rate rather than to alteration in the duration of anagen.

The shorter and thinner hairs also had a much shorter region of pigniented medulla. A progressive decrease in the extent and continuity of the medulla could be detected after 3 cycles of treatment.

Sebaceous secretion was also reduced after 2 cycles of treatment; and there was thereafter steady improvement of the pustular acne.

Sex hormone binding globulin levels were low before treatment, unaltered by a first cycle of cyproterone acetate alone, but increased by addition of ethinyl oestradiol. Gonadotrophins remained low throughout, while testosterone and androstenedione levels, initially high, were substantially suppressed.