The Effect of Platelet‐Rich Plasma in Hair Regrowth: A Randomized Placebo‐Controlled Trial

Platelet‐rich plasma (PRP) as a treatment for male pattern hair loss was investigated in a randomized, placebo‐controlled study in which 20 men received PRP on half of their scalp and placebo on the other. Patients received 3 treatments at 30‐day intervals. Hair regrowth was quantified by a blinded evaluator using computerized trichograms. Patients were followed for 2 years; study endpoints were hair regrowth, hair dystrophy as measured by dermoscopy, burning or itching sensation, and cell proliferation as measured by Ki‐67 evaluation. At the end of three treatment cycles, clinical improvement was seen in several parameters. Four of 20 patients experience continued hair loss and required retreatment. Platelet‐rich plasma (PRP) has emerged as a new treatment modality in regenerative plastic surgery, and preliminary evidence suggests that it might have a beneficial role in hair regrowth. Here, we report the results of a randomized, evaluator‐blinded, placebo‐controlled, half‐head group study to compare, with the aid of computerized trichograms, hair regrowth with PRP versus placebo. The safety and clinical efficacy of autologous PRP injections for pattern hair loss were investigated. PRP, prepared from a small volume of blood, was injected on half of the selected patients' scalps with pattern hair loss. The other half was treated with placebo. Three treatments were administered to each patient at 30‐day intervals. The endpoints were hair regrowth, hair dystrophy as measured by dermoscopy, burning or itching sensation, and cell proliferation as measured by Ki67 evaluation. Patients were followed for 2 years. Of the 23 patients enrolled, 3 were excluded. At the end of the 3 treatment cycles, the patients presented clinical improvement in the mean number of hairs, with a mean increase of 33.6 hairs in the target area, and a mean increase in total hair density of 45.9 hairs per cm2 compared with baseline values. No side effects were noted during treatment. Microscopic evaluation showed the increase of epidermis thickness and of the number of hair follicles 2 weeks after the last PRP treatment compared with baseline value (p < .05). We also observed an increase of Ki67+ keratinocytes in the epidermis and of hair follicular bulge cells, and a slight increase of small blood vessels around hair follicles in the treated skin compared with baseline (p < .05). Relapse of androgenic alopecia was not evaluated in all patients until 12 months after the last treatment. Aft