A new study has identified a promising new treatment option for hair loss.

Researchers from the University of Manchester's Centre for Dermatology Research found that a drug originally developed as a treatment for osteoporosis has a dramatic stimulatory effect on human hair follicles donated by patients undergoing hair transplantation surgery.

Only two drugs -- minoxidil and finasteride -- are currently available for treatment of male-pattern balding (androgenetic alopecia).

However, both of these have moderate side effects and often produce disappointing hair regrowth results. The only other option available to patients is hair transplant surgery.

In a PhD project, Dr Nathan Hawkshaw and colleagues investigated new ways to promote human hair growth.

First, they examined the molecular mechanisms of an old immunosuppressive drug, Cyclosporine A (CsA), which has been used since the 1980s to suppress transplant rejection and autoimmune diseases.

The drug often has severe side-effects, the least serious of which is that it enhances cosmetically unwanted hair growth.

After carrying out a full gene expression analysis of isolated human scalp hair follicles treated with CsA, the team found that CsA reduces the expression of SFRP1, a protein that inhibits the development and growth of many tissues, including hair follicles.

The inhibitory mechanism is completely unrelated to CsA's immunosuppressive activities, making SFRP1 a new and highly promising therapeutic target for anti-hair loss strategies, the University of Manchester said.

Dr Hawkshaw then found that WAY-316606, a compound used to treat osteoporosis, targets the same mechanism as CsA by specifically antagonising SFRP1.

This suggests that WAY-316606 or similar compounds may promote hair growth to the same magnitude as CsA or even better, but without patients suffering the same side effects.

The findings have been published in the open access journal PLOS Biology.