About 55 million American men have some degree of hair loss, thus creating a potentially big market for an effective at-home treatment.

The HairMax LaserComb may be an option for men who don’t want to pay for hair restoration surgery but who also don’t have high expectations. It delivers a specific wavelength of light that stimulates the hair follicle, says its manufacturer, Lexington International.

In studies by the manufacturer, the device increased the number of thick hairs in 93 percent of 120 users. The average increase in hair density was 19 hairs per square centimeter — roughly a 20 percent improvement in someone with thinning hair.

The device costs $545 and must be used 10 to 15 minutes a day, three times a week to maintain the effect.

In contrast, laser hood treatments, which are available in clinics and cover the entire scalp, can cost hundreds of dollars per treatment and need to be repeated at least twice a week.

Hair transplants provide a more permanent solution but typically cost thousands of dollars. Topical medications, such as Rogaine, run about $10 per bottle for the generic but produce only modest results for some users.

The laser hair comb is not backed by randomized, controlled studies done by independent researchers, says Dr. Paul Cotterill, president of the International Society of Hair Restoration Surgery. The device may be best suited for men who are serious about hair regrowth, such as those who undergo hair transplantation and want to augment the result at home, he says.

“This new laser comb won’t hurt, and it may help at maintaining hair,” Cotterill says. “But I want to see third-party studies — studies that have not been done by the people who produced it.”

Other laser hair regrowth devices are on the market but haven’t received FDA clearance to make claims of effectiveness. Sunetics, which sells the Laser Hair Brush, is applying for FDA clearance, says John Carullo, the company’s marketing director.