Poly-D,L-lactic acid (PDLLA) scalp microinjection protocol with optional light microneedling priming for non-scarring alopecia: A prospective pilot case series

Abstract

Background: PDLLA demonstrates angiogenic and regenerative properties that may support hair regrowth by enhancing perifollicular perfusion. Objective: To evaluate clinical improvement after PDLLA scalp microinjection in 20 patients using standardized photography and Global Aesthetic Improvement Scale (GAIS) rated by two independent physicians. Methods: Twenty adults with non scarring alopecia received PDLLA scalp microinjections at baseline and week 4 (optional booster at week 8). Optional light microneedling priming (0.5-0.8 mm) was performed immediately before PDLLA injection in 14/20 patients to facilitate distribution. Primary endpoint was physician rated GAIS at week 12; secondary endpoints included patient GAIS and safety. Images were acquired with fixed camera to scalp distance and lighting. Results: Physician GAIS improved in 90% of patients at week 12 (mean f SD 3.3 f 0.6) and was maintained at week 24 (3.1 f 0.7). Patient reported GAIS was 3.2 f 0.7 at week 12. No serious adverse events occurred. Conclusions: In this pilot uncontrolled case series, PDLLA scalp microinjections were associated with physician-rated GAIS im-provement over 12-24 weeks with favorable short-term tolera-bility. Given the subjective endpoint, the absence of a compara-tor arm, and optional microneedling priming in a subset of pa-tients, the findings are preliminary and require confirmation in controlled studies with objective trichologic measurements and longer follow-up. (c) 2026 The Authors. Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)