A company called iGrow sells a headpiece that uses LED at a certain light spectrum to combat certain hair loss types.
A page on the iGrow website details the research results from a clinical study and includes links to studies using men and women.
I also found more support for the idea in a Wall Street Journal story. It says that according to scientific researchers, “low-level lasers are safe and likely do act on cellular compounds that can spur hair growth.”
The iGrow device uses Low Level Light Therapy, which deploys laser or light energy below a specific energy threshold and within a specific wavelength.
You can get a closer look at the iGrow device and material that supports their use at the DIY Hair Restoration website.