Longitudinal biomarker trajectories accompanying trichoscopic change after PRP-based regimens for alopecia: a complementary multi-marker analysis of a real-world cohort.

Platelet-rich plasma (PRP) is widely used in nonscarring alopecia, yet the biological context accompanying measurable trichoscopic change in routine practice remains incompletely described. This study aimed to provide a complementary longitudinal analysis of the same real-world treatment cohort, focusing on within-subject trichoscopic change and paired biomarker trajectories rather than on baseline response stratification. In this ambispective observational cohort, participants underwent paired baseline (T1) and follow-up (T2) assessments after PRP, PRP + exosomes, PRP + nutricomplex, or nutricomplex alone. Total hair density (hairs/cm2) was summarized as absolute change (Δ) and percent change (%Δ). Longitudinal systemic profiling included complete blood count (CBC)-derived inflammatory indices-neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), systemic immune-inflammation index (SII), platelet-to-lymphocyte ratio (PLR), and systemic inflammation response index (SIRI)-as well as selected soluble markers, including vitamin D, tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), and transforming growth factor-beta 1 (TGF-β1). Paired changes were evaluated using Wilcoxon signed-rank tests, between-regimen differences in %Δ density with Kruskal-Wallis testing, and biomarker-change associations with Spearman correlation and FDR control. Among 129 participants, total hair density increased from T1 to T2, although the magnitude of improvement varied substantially across individuals. Regimen-level %Δ density showed numerical dispersion without statistically conclusive between-group separation. CBC-derived indices and soluble markers also displayed heterogeneous paired trajectories, and exploratory correlations suggested that selected biomarker change-scores tracked with %Δ density. This manuscript extends the cohort-level narrative by showing that early trichoscopic improvement under PRP-based care is accompanied by heterogeneous longitudinal biomarker modulation. Framed as a companion, trajectory-oriented analysis, the study supports interpreting response heterogeneity through paired clinical-biomarker dynamics rather than through a single summary endpoint alone.