Lasers for treatment of androgenetic alopecia: an in-depth analysis.

With recent developments in laser technologies and growing demand for alternative treatments, laser therapy has been increasingly studied as a treatment for androgenetic alopecia (AGA). Low-level laser therapy (LLLT) and fractional laser therapies have been marketed as safe and effective options for treating AGA in comparison with traditional drug therapies, which are associated with unwanted side effects. We discuss the history of development and implementation of laser devices for treatment of hair loss and outline the proposed mechanism of action for LLLT and fractional lasers. Additionally, we summarize the evidence of efficacy for LLLT and fractional laser monotherapies in the treatment of AGA and assess potential risk of bias in available clinical studies. While evidence is still mounting, there exists some congruency in proposed mechanisms for the stimulation of hair follicles by laser therapy. Laser light is believed to foster a supportive microenvironment for the hair follicle, through improved vascularization and modulation of inflammation, and directly stimulate growth signaling in the follicle. As for evidence of clinical efficacy, studies of LLLT and fractional laser monotherapies have reported improvement in AGA markers from baseline values. However, these studies have a relatively small sample size and our risk of bias assessment suggests some concerns in procedural design. Although laser therapy represents a safe alternative treatment option for AGA, its evidence of efficacy is hindered by a lack of large-scale, high-quality clinical trials, susceptibility to bias, and a wide range of devices, treatment protocols and parameters.