摘要

Objectives: To evaluate whether adding topically delivered, mesenchymal stromal cell–derived exosomes (MSC‑Exo) enhances the clinical, trichoscopic, histologic and molecular benefits obtained from combined 1550 nm Er:Glass + 1927 nm Thulium non‑ablative fractional laser therapy in adults with moderate androgenetic alopecia, and to define best‑practice parameters for laser–exosome regenerative protocols. Introduction: Fractional photothermolysis at 1550 nm stimulates dermal Wnt/β‑catenin and angiogenesis, whereas 1927 nm creates epidermal micro‑channels that magnify topical penetration. MSC‑Exo carry anagen‑promoting miRNAs and growth factors, yet scalp uptake is limited. A dual‑laser platform followed by MSC‑Exo could synergistically counter follicular miniaturisation and outperform laser monotherapy in androgenetic alopecia (AGA). Materials / method: IRB‑approved, randomised, assessor‑blinded pilot; 18 adults with AGA (Norwood II–IV / Ludwig I–II) allocated 1:1 to (A) laser‑only or (B) laser + MSC‑Exo. Bi-Weekly sessions ×6: 1550 nm 6 mJ, 300 MTZ cm² (2 passes) then 1927 nm 5 mJ, 120 MTZ cm² (1 pass). In the first and second sessions, Group B was administered 2 ml of 1 × 10⁹ MSC-Exo/mL under 4 hours of occlusion. The primary outcome measured was the change in terminal hair density, assessed using a Folliscope.. Secondary: shaft calibre, anagen:telogen, VisioFace‑3D coverage, β‑catenin & Ki‑67 IHC. Results: All participants completed. Terminal density rose from 152 ± 17 → 179 ± 18 hairs cm⁻² in Group A and 154 ± 18 → 202 ± 20 in Group B (p = 0.014). Shaft diameter +8.0 ± 2.2 µm vs +12.3 ± 2.4 µm (p = 0.006). Anagen:telogen improved to 2.6 vs 3.1 (p = 0.009). β‑catenin nuclei +64 % vs +112 %; Ki‑67 +38 % vs +71 %. Cohen d for primary endpoint = 1.29. No fibrosis; only transient erythema ≤ 2 days. Conclusion: Dual‑wavelength non‑ablative fractional laser significantly enhances hair density and calibre in moderate AGA; immediate post‑laser MSC‑Exo application further amplifies and sustains these gains without added morbidity. This integrated, drug‑free regenerative protocol is well‑tolerated, easily incorporated into clinical practice and warrants validation in larger, sham‑controlled trials.