Re-Evaluating Cyclosporine A as a Hair Growth–Promoting Agent in Human Scalp Hair Follicles

The study by Nathan Hawkshaw and colleagues from 2015 investigated the effects of Cyclosporine A (CSA) on human scalp hair follicles and found that CSA treatment for 6 days significantly increased hair shaft production and prolonged the anagen phase of the hair cycle. Histological analysis showed increased melanin, higher proliferation of hair matrix keratinocytes, and reduced fibroblast migration in the dermal papilla. The study also revealed that while NFATc1 was activated in human hair follicle stem cells, NFATc2 did not follow the same expression pattern as in rodents, indicating a potential difference in the mechanism of CSA's effects on human hair follicles. The study concluded that CSA inhibits the transition to the catagen phase in human hair follicles, but the underlying mechanisms may differ from those in rodents. The number of hair follicles tested varied from 6 to 43, pooled from multiple patients.