Inhibition of Skin 5α-Reductase by Oral Contraceptive Progestins In Vitro

In the 2000 study, researchers tested the effects of oral contraceptive progestins on the enzyme 5α-reductase in human skin homogenate from 30 healthy women aged 18-26 years. They discovered that norgestimate was the most effective at inhibiting 5α-reductase, with an IC50 value of 10 µM, indicating its potential for treating androgen excess disorders like hirsutism, acne, and alopecia in women. Other progestins such as levonorgestrel, dienogest, cyproterone acetate, and gestodene were less effective, with IC50 values ranging from 52 to 98 µM. The study concluded that norgestimate and dienogest could be beneficial in treating clinical hyperandrogeny due to their minimal androgenic potential and effective inhibition of 5α-reductase.