The FDA gave a product called iGrow Hair 510(k) clearance and the helmet-like device is already being sold for $695, with a prescription.
Florida-based Apira Sciences says that its device reverses male pattern baldness using a low-level light therapy, to "energize" cells and encourage hair follicles to start working again over the course of 4 to 6 months.
The FDA clearance is based on a 44-patient study of men with androgenetic alopecia, or male pattern baldness. Over 16 weeks, a greater percentage of hair growth was seen for men in the treatment group versus those in the placebo group.
The helmet is intended for night-time use and is fitted with headphones and a standard audio jack.