What Exactly Is Platelet, and Why Is It Popular for Treating Hair Loss?

Hair loss is one of the most visible and emotionally charged changes that people experience over time. From medical to cosmetic contexts, the desire to understand and treat it has led to a wide range of therapies. Among them, platelet-rich plasma (PRP) therapy has attracted considerable attention.

But what exactly is platelet-rich plasma, how does it work, and what does the scientific evidence really say about its effectiveness?

Platelets are small cellular fragments circulating in our blood, crucial for wound healing and tissue repair. When an injury occurs, they gather at the damaged site and release proteins known as growth factors—biological molecules that trigger cell division, angiogenesis (formation of new blood vessels), and tissue regeneration. In PRP therapy, this natural healing mechanism is concentrated and redirected toward the scalp.

The procedure begins with drawing a small quantity of the patient’s own blood. This blood is then placed in a centrifuge—a machine that spins it rapidly—to separate its components. The resulting plasma layer, rich in platelets, is collected and injected into areas of the scalp affected by thinning or miniaturized hair follicles. The expectation is that this infusion of growth factors can reactivate dormant follicles and improve hair shaft thickness. The concept seems intuitively appealing, but how solid is the evidence behind it?

Why PRP Became a Trend in Hair Restoration

PRP therapy gained traction for several reasons. First, it uses the patient’s own biological material, minimizing the risk of allergic reactions or contamination. Second, it is considered minimally invasive and requires little to no recovery time. Finally, it aligns with a broader trend in regenerative medicine: stimulating the body’s own capacity for healing rather than introducing synthetic compounds. However, popularity is not synonymous with proof. When analyzing PRP critically, it is essential to ask: do clinical trials confirm these expectations?

What the Research Really Shows

Scientific studies over the past decade have explored PRP’s potential, but the findings vary due to differences in methods, preparation techniques, and patient populations.

In 2015, a randomized, placebo-controlled trial by Gentile and colleagues in Italy tested PRP in 23 men with androgenetic alopecia over three months. Using phototrichograms—microscopic imaging to count and measure hair strands—the researchers found an increase in hair density among PRP-treated patients compared with the placebo group. While the results were statistically significant, the small sample and short duration limited broader conclusions (Gentile et al., 2015).

A year later, Alves and Grimalt (2016) published a systematic review of twelve clinical studies involving more than 200 participants, both men and women, followed for periods ranging from three to twelve months. Most trials reported improvements in hair density and thickness, but the authors emphasized a lack of standardization in PRP preparation and injection techniques, which made it difficult to compare results across studies.

Further scrutiny came from a 2019 meta-analysis by Gupta and colleagues in Canada, who examined ten trials involving 262 participants. They reported a moderate but statistically significant improvement in hair count in patients treated with PRP compared with controls. Yet again, they noted that most studies had small sample sizes and short follow-up durations, making long-term efficacy uncertain.

In 2021, Mapar and his team in Iran conducted a double-blind, randomized clinical trial comparing PRP injections with topical minoxidil 5% in 60 men over six months. Both groups showed improvement, but PRP acted faster in the early months, while minoxidil’s benefits persisted longer after treatment ended. The study concluded that PRP might serve as a useful complement to pharmacological treatments rather than a replacement.

The Mechanism: How PRP Might Influence Hair Growth

PRP’s biological action is attributed to its concentration of growth factors, such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF).

These molecules stimulate local stem cells in the hair follicle and enhance vascularization around the follicular bulb, potentially improving nutrient and oxygen supply. In theory, this environment favors the transition of follicles from the resting (telogen) phase to the active (anagen) phase of growth.

However, this mechanism is still largely theoretical. The degree of platelet concentration, centrifugation speed, and frequency of injections significantly influence the final composition of the PRP. Inconsistent methods between clinics mean that two treatments labeled “PRP” can differ dramatically in potency and outcome. Without standardized preparation protocols, reproducibility remains one of PRP’s greatest challenges.

The Limits of PRP and the Future of Research

PRP is not a cure for baldness. Its effects are most visible in early or moderate stages of hair loss, where follicles are still present but weakened. In advanced cases, where follicles have already atrophied, PRP offers limited benefit. Moreover, the treatment’s duration of efficacy remains uncertain, often requiring multiple sessions and periodic maintenance.

**Some recent investigations have begun combining PRP with other interventions **—such as microneedling or low-level laser therapy—to enhance the penetration and biological activation of growth factors. Preliminary evidence suggests these combinations may offer better outcomes, but more large-scale, long-term studies are needed.

What We Should Really Take Away

PRP embodies a compelling idea: using our own biology to counteract the biological process of hair thinning. However, it remains a developing field where the enthusiasm often surpasses the scientific consensus. Patients should view PRP as an experimental therapy with potential benefits, but also with clear limitations and inconsistencies in evidence. Understanding these nuances allows us to make informed decisions rather than relying on the allure of novelty.

References

Alves, R., & Grimalt, R. (2016). Platelet-rich plasma in combination with other therapies for hair loss: Systematic review and meta-analysis. Dermatologic Surgery, 42(12), 1501–1511. https://pubmed.ncbi.nlm.nih.gov/27341630/

Gentile, P., Garcovich, S., Bielli, A., Scioli, M. G., Orlandi, A., & Cervelli, V. (2015). The effect of platelet-rich plasma in hair regrowth: A randomized placebo-controlled trial. Stem Cells Translational Medicine, 4(11), 1317–1323. https://pubmed.ncbi.nlm.nih.gov/26044618/

Gupta, A. K., Carviel, J. L., & Abramovits, W. (2019). Platelet-rich plasma for the treatment of alopecia: A systematic review and meta-analysis. Journal of Cutaneous Medicine and Surgery, 23(1), 9–17. https://pubmed.ncbi.nlm.nih.gov/31290678/

Mapar, M. A., Yazdanpanah, M. J., Farajzadeh, S., & Shakeri, M. (2021). Comparison of platelet-rich plasma versus minoxidil in the treatment of androgenetic alopecia: A randomized clinical trial. International Journal of Dermatology, 60(8), 1008–1015. https://pubmed.ncbi.nlm.nih.gov/33958353/