PRP for hair loss: what the evidence shows

Platelet-rich plasma (PRP) is a concentrate of platelets prepared from a patient's own blood and delivered to the scalp, usually by injection. Platelets release growth factors and cytokines involved in tissue repair, and several studies show PRP can improve hair density and thickness in pattern hair loss. Its exact mechanism is still not fully explained.

How is PRP prepared and given?

A small amount of blood is drawn and spun in a centrifuge to separate the platelet-rich layer. That layer is then delivered to the thinning areas of the scalp. Because it comes from the patient's own blood, it carries no risk of rejection.

Does PRP work for hair loss?

A 2022 review in Drug Design, Development and Therapy concluded that several studies show PRP can be used effectively for hair loss, while noting that the exact mechanism has not been fully elucidated. Results vary with the preparation method, the number of sessions and the type of hair loss.

In a randomised trial led by Professor Nilforoushzadeh, 40 people with androgenetic alopecia received PRP either by injection or by microneedling, in two sessions a month apart. Two months after the last session:

Method	Hair count	Hair thickness
PRP injection	about 62% higher	about 59% higher
PRP with microneedling	about 88% higher	about 51% higher

Both groups improved significantly, the difference between them was not statistically significant, and microneedling was better tolerated. The trial was small and short, so it supports PRP as an option rather than proving it superior to established medicines.

Who is PRP suited to?

PRP is most often used for pattern hair loss, alone or combined with medical treatment, laser or a hair transplant. It is not a replacement for diagnosis: in autoimmune or scarring hair loss the first priority is controlling the underlying disease. For hair loss that has not responded to PRP, newer cell-free options such as exosomes are being studied.