Does frequency matter? Optimizing PRP injection intervals for hair regrowth in real practice

Objectives: To evaluate the clinical impact of different PRP injection intervals—weekly, biweekly, and monthly—and to propose a practical framework for optimizing treatment frequency in hair regrowth Introduction: Platelet-rich plasma (PRP) is widely used for hair restoration; however, treatment outcomes remain variable in clinical practice. One of the most overlooked factors is injection frequency. While most protocols recommend monthly sessions, real-world practices vary significantly, and optimal treatment intervals remain unclear. This gap may contribute to suboptimal outcomes despite appropriate patient selection. Materials / method: Patients with comparable patterns of hair thinning were treated using three different PRP protocols: weekly, biweekly, and monthly sessions. Clinical outcomes were assessed through serial photographic evaluation, focusing on hair density, thickness, and overall scalp response. Observations also included treatment tolerance and patient adherence. A practical optimization model was developed based on observed response patterns. Results: Differences in clinical response were observed across treatment intervals. More frequent sessions demonstrated earlier visible improvement in some patients, while others showed comparable outcomes with less frequent protocols. Variability in response suggested that a fixed interval may not be optimal for all patients. Treatment tolerance and adherence also influenced long-term outcomes. Conclusion: PRP efficacy in hair restoration is not solely dependent on the treatment itself but is significantly influenced by injection frequency. A personalized, response-based approach may offer more consistent and effective results than fixed protocols. Optimizing treatment intervals represents a key step in advancing PRP outcomes in real-world clinical practice.