— -- A new hair-loss treatment is giving hope to millions of people with thinning hair.
The treatment, called Platelet Rich Plasma therapy -- or PRP -- could help regrow and thicken hair without surgery, drugs or expensive treatments, experts say.
PRP relies on the patient's own platelets. The patient's blood is drawn and placed in a machine, where the plasma is separated from the blood and injected directly into that patient's scalp.
The platelets contain growth factors that stimulate the regrowth and thickening of hair follicles.
The research is preliminary, but it's promising, experts say.
"This is the best kept secret in the world," Dr. Jeffrey Rapaport, a New Jersey dermatologist, told ABC News.
Tanisha Jimenez has used PRP and she says it has worked for her.
Jimenez said that years of pulling her hair back caused her to lose some around her face. Just weeks after her first treatment, her hair started to regrow, she said.
"It's amazing," she said.
Rapaport noted, though, that this isn't considered a cure for baldness.
"It's a treatment … What we're doing is increasing the diameter of the size of the hair follicle," he said. "And we're keeping the hairs that would stop growing in the growing phase."
The best candidate for PRP is someone who has recently started losing hair, Rapaport said. It won’t work for those who are completely bald, and it won’t regrow all the lost hair, he said.
The entire process, including the injection, takes about 90 minutes and costs $400 or more per session.
Rapaport recommends one treatment per month for the first four months and then two maintenance treatments per year. Some doctors add other hair-growth medications to the mix.