Hair PRP: does it work, how many sessions and what results to expect

Hair PRP involves drawing a small amount of your own blood, separating the platelet-rich fraction by centrifugation, and injecting it into the scalp. The platelets release growth factors that stimulate the follicles. The evidence shows increased hair density in androgenetic alopecia and in alopecia areata, particularly when combined with other treatments. It is usually given as three to four initial sessions four weeks apart, followed by maintenance. Results begin to show around the third month. It is not a permanent treatment and does not replace a transplant in advanced baldness.

Does hair PRP actually work?

It works in specific situations, and that distinction is everything.

In published reviews and meta-analyses, PRP shows a consistent increase in hair density in androgenetic alopecia — the number of hairs per square centimetre rises. Its effect on the thickness of each hair is less consistent across studies.

In alopecia areata, results are superior to placebo and comparable to injectable corticosteroids, with fewer adverse effects.

What the evidence does not support: growing hair where the follicle has already disappeared. PRP stimulates follicles that still exist, even miniaturised ones. In an area that has been completely bald for years, there is nothing left to stimulate.

So the right question is not "does PRP work?" but "does PRP work in my case?" — and that depends on the type of alopecia, how long it has been going on, and the state of the follicles, which is assessed by trichoscopy.

How many hair PRP sessions are needed?

The most widely used protocol is three to four initial sessions, four weeks apart.

This is followed by a maintenance phase, generally one session every three to six months, adjusted to each person's response.

A single session does not produce a lasting result. Anyone who has one and gives up never finds out whether it would have worked.

How long before results show?

There is no visible change in the first few weeks, and it is important to know that from the outset.

The hair growth cycle is slow. Reduced shedding is usually the first sign, at around six to eight weeks. Visible density gain generally appears between the third and sixth month.

Assessment is done through standardised photographic comparison and trichoscopy, not impression. What you notice in the mirror every day is unreliable in both directions.

How long does hair PRP last?

The effect is not permanent.

Androgenetic alopecia is progressive and driven by hormonal and genetic factors that PRP does not eliminate. Without maintenance, density tends to return to baseline over the following months.

This is why PRP is planned as ongoing treatment rather than a one-off procedure. Anyone looking for a definitive fix in a single session will be disappointed — better to know that beforehand.

Does hair PRP hurt?

There is discomfort, particularly with injections in the frontal area, where the scalp is more sensitive.

The blood draw is the same as a routine blood test. The injections are superficial and quick. Topical anaesthetic is applied beforehand, and in more sensitive patients local cooling or infiltrative anaesthesia can also be used.

Most people describe the session as uncomfortable but tolerable, and return to normal activity the same day. Scalp tenderness may persist for a day or two.

How much does hair PRP cost?

The cost depends on the number of sessions, the protocol and the centrifugation equipment used, which varies considerably between clinics.

More relevant than the price per session is understanding the full plan: how many initial sessions, at what interval, and what maintenance is expected. A low price per session within a poorly defined protocol ends up costing more and delivering less.

The quote is given after the assessment consultation, because only then is the number of sessions for each case known.

Who is hair PRP suitable for?

It tends to work well in:

• Early or moderate androgenetic alopecia, with follicles still present

• Alopecia areata, alone or alongside other treatments

• Telogen effluvium with prolonged shedding

• As an adjunct to hair transplant, before or after

• People who cannot tolerate or do not want oral medication

It tends to work poorly, or is not indicated, in:

• Advanced baldness, with areas without follicles for several years

• Clotting disorders or anticoagulant therapy

• Active scalp infection

• Active haematological or oncological disease

• Anyone expecting a result without maintenance

Hair PRP or hair transplant?

They are different things, not competing options.

A transplant moves follicles from a donor area to an area without hair. It is the only way to repopulate a region where the follicle no longer exists.

PRP stimulates follicles that are still present. It does not create new ones.

In practice they are combined: PRP can be used before a transplant to improve scalp quality, and afterwards to support graft survival and slow the loss of native hair, which is still there and still falling.

Having a transplant without treating the underlying alopecia is a frequent mistake: the grafts remain, but the surrounding hair keeps thinning, and the result unravels over time.

PRP with minoxidil, or on its own?

The combination outperforms either treatment alone.

Studies comparing PRP plus topical minoxidil against minoxidil alone show greater terminal hair density in the combined group.

When compared directly with minoxidil alone in moderate androgenetic alopecia, PRP shows similar efficacy. This suggests its place is as a complementary treatment within a plan, rather than a replacement.

Is hair PRP safe?

The safety profile is favourable, because the material injected is the patient's own blood — there is no risk of rejection or allergic reaction to the product.

Reported adverse effects are almost entirely limited to injection-site pain and transient redness.

The real risk lies in the procedure, not the product. It requires blood collection, centrifugation and injection under aseptic conditions, performed by a doctor. Handling blood outside an appropriate clinical setting is the main danger associated with this treatment.

Before booking, confirm who performs the procedure and where. It should be a doctor, in a clinical environment.

Sources

• Meta-analyses and systematic reviews on PRP in androgenetic and areata alopecia published between 2023 and 2024

• American Academy of Dermatology — androgenetic alopecia recommendations

• European Academy of Dermatology and Venereology

• Portuguese Society of Dermatology and Venereology (SPDV)

Written and reviewed by Dr Ellene Papazis, dermatologist accredited in Portugal and Brazil, practising trichology. Consultations in Porto, Portugal.

Updated 25 July 2026.