Evaluation of the cosmetic efficacy of salmon tissue-derived exosomes and platelet-rich plasma therapy in patients with androgenetic alopecia: a randomized controlled clinical trial

BACKGROUND: Androgenetic alopecia is a chronic progressive disorder characterized by follicular miniaturization, perifollicular fibrosis, and microcirculatory impairment. Conventional therapies (minoxidil, finasteride) have limited efficacy and are associated with adverse effects. In recent years, regenerative approaches—platelet-rich plasma (PRP), exosomes, microneedling with growth factors, and others—have been widely used; however, direct comparative data on their cosmetic effectiveness and pathogenetic rationale (including terminal/vellus hair ratio, anagen proportion, and tolerability) remain extremely limited. AIM: To conduct a comparative evaluation of the visible cosmetic effect and pathogenetic rationale of salmon tissue-derived exosomes and PRP in patients with mild-to-moderate androgenetic alopecia. METHODS: A two-arm, randomized, controlled clinical trial involved 40 participants (14 men with Norwood–Hamilton stages III–IV and 6 women with Ludwig stages I–II per group). Patients in group 1 (n=20) received four exosome sessions every 14 days; those in group 2 (n=20) received five PRP sessions at the same interval. Assessments were performed before treatment and 12 weeks after the last procedure using phototrichography (ARAMO SG, TrichoScan v.4.5) and included hair density, percentage of vellus hairs, terminal/vellus (T/v) ratio, anagen proportion, mean hair diameter, and anisotrichosis. Adverse events were recorded at each visit. RESULTS: Hair density increased by 44.4±7.8 hairs/cm² in the exosome group and by 26.3±6.5 hairs/cm² in the PRP group (difference of 18.1 hairs/cm²; p 0.001). Vellus hair proportion decreased by 37.0% vs 21.2% (p=0.003); the T/v ratio increased from 2.4 to 9.7 vs 4.8 (p=0.001); anagen proportion increased by 36.4% vs 23.4% (p=0.002); mean hair diameter increased by 22.4 μm vs 12.4 μm (p 0.001), respectively. Transient local reactions were less common in the exosome group (40% vs 70%; p=0.028). No serious adverse events were reported with either treatment. CONCLUSION: Salmon tissue-derived exosomes demonstrated significant advantages over PRP therapy across the majority of the evaluated parameters (including the terminal/vellus hair ratio, anagen proportion, and tolerability), even with fewer sessions. These results suggest that exosomes may have a more profound impact on mechanisms involved in terminal hair miniaturization and the hair growth cycle.