Devices that emit low-energy laser light may help new hair grow. They come as hats, helmets, caps, combs, and headbands andt use low level laser technology to stimulate the scalp, hair follicles, promoting hair growth and blood flow. They're available in some clinics and for home use. Several are approved for both men and women, and studies show they do work. But it might take 2-4 months before you see results. Keep in mind: The FDA doesn’t require the same rigorous testing for devices as for medicines. The long-term safety and effects aren’t known.