Comparative efficacy and tolerability of platelet-rich plasma and injectable platelet-rich fibrin in male androgenetic alopecia: A prospective split-scalp interventional study

Abstract

Background: Androgenetic alopecia (AGA) is characterized by progressive follicular miniaturization. 
Platelet-rich plasma (PRP) is used as an autologous regenerative treatment, whereas direct comparative 
evidence for injectable platelet-rich fibrin (PRF) remains limited.
Methods: In this prospective split-scalp interventional study, 35 men with Hamilton-Norwood Grade 
II-IV AGA received PRP on the right scalp half and PRF on the left; allocation was fixed, and no formal 
blinding was documented. Three sessions were administered four weeks apart, with final assessment 
one month after the third session. Trichoscopically measured hair density, Hamilton-Norwood grade, 
and adverse effects were compared using paired tests.
Results: Baseline trichoscopy showed hair-diameter variability in 31 (88.57%), single-hair follicular 
units in 29 (82.86%), peripilar sign in 24 (68.57%), and yellow dots in 14 (40.00%) participants. Baseline 
hair density was comparable between PRP and PRF sides (132.91 ± 12.02 vs 133.00 ± 11.87 hairs/cm²; 
p = 0.727). Mean gain was 19.06 ± 2.11 hairs/cm² with PRP and 25.77 ± 2.53 hairs/cm² with PRF; the 
paired difference was 6.71 hairs/cm² (95% CI, 6.39-7.04; p < 0.001). One-grade improvement occurred 
in 11 (31.43%) PRP-treated and 26 (74.29%) PRF-treated halves. Adverse effects occurred on 8 (22.86%) 
PRP-treated and 1 (2.86%) PRF-treated half (p = 0.039).
Conclusion: Both preparations improved short-term outcomes; under the fixed-side split-scalp protocol, 
PRF was associated with greater hair-density gain and fewer minor adverse effects.