The Effectiveness of Allogeneic Mesenchymal Stem Cells Therapy on Hair Regrowth in Androgenetic Alopecia: A Randomized, Double-Blind, Placebo Control Trial

Abstract

Objectives: The objectives of the study (i) to compare the mean hair regenerative effect of allogeneic bone marrow-derived MSCs versus Placebo, in treatment of AGA, (ii) to determine and compare the investigator’s assessment and patient satisfaction in both groups.

Methodology: This randomized double-blind placebo-controlled trial was conducted at Dermatology department of National University of Medical Sciences in collaboration with Department of Cellular Therapy and Regeneration, National Institute of Blood and Marrow Transplant, Rawalpindi, Pakistan between January 2025 and June 2025. Of 131 patients screened, 120 eligible adult patients with clinically diagnosed AGA (Hamilton-Norwood II–VII) were randomized 1:1 using an online randomization tool to receive either a single intradermal injection of 2 million BM-MSCs (intervention group, n=60) or placebo (control group, n=60) into affected scalp areas. Twelve patients (6 in each group) were lost to follow-up; 108 participants completed the study and were included in the final analysis (n=54 per group; intention-to-treat). Blinding was maintained for both participants and investigators. Primary endpoints were changes from baseline in total hair count and hair diameter at 12 weeks, assessed via phototrichoscopy on a marked target area. Secondary outcomes included investigator-assessed global photographs and patient satisfaction (measured via a Likert scale).

Results: At 12 weeks, the BM-MSC group showed statistically significant improvements in both total hair count (mean difference; p<0.001) and hair diameter (mean difference; p<0.001) compared to the placebo group. Subjective patient satisfaction and investigator global assessment scores also improved significantly in the BM-MSC group (p<0.001). No serious adverse events were reported. Minor local side effects occurred in a few patients and resolved spontaneously.

Conclusions: Allogeneic BM-MSC therapy appears to be a safe and effective treatment for androgenetic alopecia, demonstrating significant improvements in hair count, diameter, and patient satisfaction at 12 weeks. These findings support further large-scale trials to confirm long-term efficacy.