Early Anagen Effluvium After Hair Transplantation: A Prospective Observational Pilot Study Comparing Follicular Storage Temperatures

Introduction: The optimal preservation temperature of follicular units (FUs) during hair transplantation remains controversial, with most available evidence derived from in vitro and animal studies. Clinical in vivo data evaluating the relationship between storage temperature and early postoperative outcomes remain limited. This study evaluates the association between follicular storage temperature and early anagen effluvium following hair transplantation.

Methods: A prospective observational pilot study was conducted involving 100 male patients undergoing follicular unit excision (FUE) hair transplantation. Patients were allocated into two sequential groups according to follicular storage temperature: hypothermic storage (8°C–12°C) and room-temperature storage (21°C–25°C). All procedures were performed by the same surgical team using standardized extraction, implantation, preservation solution, and postoperative protocols. Early anagen effluvium was clinically assessed at 40 days postoperatively. Hair growth outcomes were evaluated during a 12-month follow-up period using standardized photographic and video documentation.

Results: Baseline demographic and surgical variables were comparable between groups. Chi-square analysis demonstrated a statistically significant difference in the distribution of early anagen effluvium between the groups (p ≤ 0.015). Patients in the room-temperature storage group demonstrated a significantly higher proportion of minimal early anagen effluvium compared with the hypothermic storage group (p ≤ 0.007). At 12 months, clinically acceptable hair growth was observed in all patients.

Conclusion: Under standardized surgical conditions, room-temperature follicular storage appears to be safe in hair transplantation procedures lasting up to six hours and may be associated with reduced early anagen effluvium compared with hypothermic preservation. These findings support the hypothesis that follicular storage temperature may influence early postoperative follicular adaptation and shedding.