Impact of Age on Response to Platelet-Rich Plasma Therapy Open Access

Platelet-rich plasma (PRP) is an increasingly utilized treatment for androgenetic alopecia (AGA) [1]. PRP utilizes autologous platelets to stimulate hair follicle activity and promote growth [1]. In osteoarthritis patients, PRP derived from younger donors has demonstrated greater regenerative effects on joints compared to PRP from older donors [2]. Despite the growing popularity of PRP for AGA, limited data exists regarding the influence of age on efficacy. Therefore, this study seeks to evaluate PRP outcomes across age cohorts.

We conducted an IRB-approved retrospective review of NYU Langone Health patients seen between November 1, 2017, and March 1, 2025. We analyzed changes in trichometric density (hairs/cm²) and width (μm) from initial to final follow-up visits within the study window across four age subgroups. Statistical significance and linear regression testing were determined using ANOVA and Rank-Based ANCOVA, respectively.

Fifty-seven AGA patients were included (68.4% female, mean age 50.3, 70.2% White, 3.5% Asian, 26.3% unknown). 59.6% were on 1+ adjunctive therapy, most commonly oral finasteride (33.3%), low-dose oral minoxidil (24.6%), oral spironolactone (15.8%), and oral dutasteride (10.5%). At the time of the initial PRP treatment at NYU, the average duration of adjunctive medication use exceeded 1 year for each agent. Notably, these treatments generally achieve the majority of their peak benefit by approximately 12 months [3‒5]. Among those aged 18–34 years (n = 14), the average number of sessions was 7, with mean increases in density and width of 20.2 hairs/cm² and 3.8 µm, respectively. The 35–49 age group (n = 17) had a comparable average of 7 sessions, with mean increases of 11.2 hairs/cm² in density and 5.8 µm in width. Patients aged 50–64 (n = 12) received 9 sessions on average and showed smaller gains: an increase of 2.6 hairs/cm² and 1.2 µm for density and width, respectively. In the 65+ group (n = 14), patients underwent an average of 14 PRP sessions and demonstrated improvements of 9.9 hairs/cm² in density and 2.6 µm in width. PRP was well tolerated across all age groups (Table 1).

ANOVA tests revealed no statistically significant differences in density (p = 0.4986) or width (p = 0.2665) changes across age groups, although younger individuals trended toward greater density improvements (Table 2). Rank-based ANCOVA testing revealed more nuanced relationships: change in width was significantly associated with baseline width (p < 0.0001), indicating that greater baseline width may be predictive of smaller increases in hair width. Significant interactions between age and PRP sessions were observed for patients aged 35–49 (p = 0.0298) and 65+ (p = 0.0339), suggesting that older patients may require more sessions to achieve similar gains in hair width (online suppl. Table 1; for all online suppl. material, see https://doi.org/10.1159/000546800). Change in hair density was significantly associated with the number of adjunctive therapies (p = 0.0499), as patients receiving more concurrent treatments experienced greater gains. In contrast, neither the number of PRP sessions (p = 0.9446) nor baseline density (p = 0.3286) showed a significant association with density changes (online suppl. Table 1). Key limitations include small sample sizes and retrospective design.

Overall, these results highlight the importance of baseline hair width, the potential for age-dependent variation in PRP efficacy, and the added benefit of multimodal therapy in enhancing hair density gains. This information may help inform PRP counseling, although future controlled prospective studies with larger cohorts are needed to validate findings and further elucidate the impact of age on PRP efficacy. While the underlying mechanisms remain unclear, one possible explanation for the observed interaction between age and number of PRP sessions is that aging may reduce the concentration or activity of regenerative components in autologous plasma, diminishing the per-session effectiveness of PRP. Alternatively, hair follicle stem cells in older individuals may respond less robustly to growth factors, thereby requiring additional treatments to achieve comparable results. Further mechanistic studies are needed to investigate these hypotheses and improve understanding of the biological factors underlying age-related differences in PRP response.

This study was performed in accordance with the Declaration of Helsinki. This human study was approved by NYU Langone Health IRB, approval No. i23-00157, and it was granted an exemption from requiring written informed consent.

Dr. Kristen I. Lo Sicco was a member of the journal’s editorial board at the time of submission. No other authors have relevant conflicts of interest to disclose.

The authors have received no external funding.

Anna Brinks: conceptualization, investigation, methodology, writing – original draft, and writing – review and editing. Deesha D. Desai: conceptualization, investigation, methodology, and writing – original draft. Caitlin Kearney and Carli Needle: investigation and writing – review and editing. Nnaemeka Anyanwu: formal analysis. Ambika Nohria, Michelle Sikora, and Christina S. Oh: investigation. Jerry Shapiro: project administration, supervision, and writing – review and editing. Kristen I. Lo Sicco: conceptualization, project administration, supervision, and writing – review and editing.

Anna Brinks and Deesha D. Desai share co-first authorship.

All data generated or analyzed during this study are included in this article and its online supplementary material. Further inquiries can be directed to the corresponding author.