The P-Shot (PRP): What the Evidence Shows

Every few weeks a man sits down and tells me he is thinking about the P-Shot. He has usually read that it is "regenerative", that it uses his own blood, and that it is natural. All three of those things are true, and none of them answers the question he came in with.

Does it work? And underneath that, quite often, there is a second question he finds harder to say out loud — will it make him bigger?

So let me answer both, and let me do it with the awkward part first. The scientific societies that have reviewed the evidence do not think it should be offered as a routine treatment yet. Not because it is dangerous. It appears to be reasonably safe. But because the evidence that it works is genuinely split, and because a treatment with split evidence sitting behind a price list is a different proposition from a treatment with split evidence sitting inside a trial.

That is not my opinion dressed up as a consensus. Three separate bodies have looked at this and reached the same place, in three different forms of words. I will show you all three below.

I am a private surgeon. I could offer you this tomorrow. I don't, and what follows is why.

What is actually in the syringe

Platelet-rich plasma — PRP — is made from your own blood. We take a sample and spin it in a centrifuge. The spinning separates the blood into layers. One of those layers is rich in platelets, the cells that clot your blood and release growth factors when tissue is injured. That layer is drawn off and injected into the penis.

The theory is straightforward, and it is not unreasonable. Growth factors help tissue repair. Erections depend on healthy blood vessels and healthy smooth muscle. So deliver growth factors to the place where the vessels have struggled, and the tissue may recover.

That is a hypothesis. It is a decent one. Whether it happens in a real penis, in a way a real man notices, is a separate question — and it is the question the trials were built to answer.

The question most men are really asking: does it make you bigger?

Most men who arrive at this page are actually looking for penile enlargement, not for a treatment for erections.

So, plainly: there is no good evidence that the P-Shot produces a permanent increase in penile size. The claim is common in promotional material but does not appear consistently in clinical trials. Neither of the two randomised trials of PRP for erections measured length or girth as an outcome at all — which tells you how seriously the research community takes the enlargement claim.

If size is the reason you are here, I would rather you read what I have written about it directly than spend money on this. Most men who believe they are small are not. The ones who are helped are helped by understanding, not by a syringe.

Does it help erections? Two good trials, two different answers

This is where honesty gets harder, because the evidence does not point one way.

The first trial said yes. In 2021 a randomised, double-blind, placebo-controlled study gave either PRP or a dummy injection, twice, a month apart. At six months, 69% of the men who had PRP had reached the minimal clinically important difference — the smallest improvement a man would actually notice — against 27% of the men who had the placebo. That gap is real and it is not small.

The second trial said no. In 2023 a study of the same design, with the same two injections a month apart, in men with mild to moderate difficulty, measured its main outcome one month after the second injection. It found 58% of the PRP group reaching that threshold and 54% of the placebo group. Both groups improved by around three points on the standard erection questionnaire. The improvement was real. It just did not depend on which injection the man had received.

The two studies are not perfectly comparable, and it is worth knowing why. The 2021 result quoted above is at six months. The 2023 headline result is at one month, though those men were followed to six months as well. Placing them side by side shows you the disagreement; it does not show you a like-for-like race.

That last point matters more than it looks, because it explains something you may have heard. Men do leave these clinics feeling better. In the 2023 trial, so did the men who were given nothing.

Two studies of the same design reached opposite conclusions. When that happens, the honest position is not to pick the one you prefer.

Neither study was large enough to settle the question on its own. When small trials disagree, the usual scientific response is not to choose a winner but to perform larger studies designed to resolve the uncertainty.

One reason the evidence remains difficult to interpret is that "PRP" is not a single standardised treatment. Different studies use different preparation methods, platelet concentrations and injection protocols, making direct comparison difficult. The authors of the positive trial say so themselves: their results, they write, cannot be extrapolated to other PRP separation systems.

It is also worth asking who benefits when that uncertainty is glossed over.

What the professional bodies say, and the part that gets left out

Three organisations have reviewed this evidence formally, and they agree.

The Sexual Medicine Society of North America concluded that restorative therapies "should be reserved for clinical trials and not offered in routine clinical practice". The American Urological Association lists platelet-rich plasma for erectile dysfunction as one that "should be considered experimental", on expert opinion — the lowest grade of evidence it uses. The European Association of Urology states that PRP injection "should be used only in a clinical trial setting".

Three separate bodies, three different forms of words, one position. That is about as close to a settled professional view as sexual medicine gets.

There is a fourth statement, and it is the one that rarely reaches a clinic's website. Presenting the position statement at the Sexual Medicine Society of North America's 22nd Annual Fall Scientific Meeting on 22 October 2021, and reported in the society's own meeting write-up, Trinity Bivalacqua finished with a blunter version of the same thought.

Until then, we should not be charging our patients for restorative therapies.

That is one clinician's phrasing rather than the society's own, and I quote it as such. I quote it because it names the part the formal wording leaves implicit. If a treatment is still being tested, the cost of testing it should not fall on the man in the chair.

Some good clinicians do offer it, and I am not going to pretend otherwise. A treatment being experimental does not make everyone who provides it a chancer. What it does mean is that anyone offering it should be telling you exactly what I have told you on this page — that the evidence is split, that the professional position is that it belongs in trials, and what it will cost you. If that is the conversation you are having, you are in careful hands. If instead you are being told that it works, ask to see what that claim is based on.

It is probably safe. That is a different claim from working

I want to be careful here, because it would be easy and cheap to frighten you.

Both randomised trials looked for harm and did not find much. No priapism, no fibrous plaques, no penile deformity, no significant bleeding problems. The 2023 trial reported one minor adverse event in each group and no major ones. Men tolerated it. If you have already had the P-Shot and nothing went wrong, that is entirely consistent with what the studies show, and there is no reason to be alarmed now.

So my argument against it is not that it will hurt you. It is that you may be paying a considerable amount for something that, in a randomised, double-blind, placebo-controlled trial — the strongest study design we have — performed no better than placebo. The money and the appointment might buy you a proper diagnosis instead.

What about Peyronie's disease, or premature ejaculation?

PRP is marketed for both, so it is worth saying where each stands.

For Peyronie's disease — curvature caused by scar tissue — the position statements I have quoted address restorative therapies for erectile dysfunction, not for curvature. So I am extending their reasoning rather than citing it: the trial evidence for PRP in Peyronie's is thinner still than for erections, and I would treat it the same way.

For premature ejaculation, which comes up often when men search for this treatment, I am not aware of trial evidence that PRP helps, and none of the three guideline documents mentions it for that purpose. That one matters, because premature ejaculation does have treatments that work. Spending on an unproven injection can delay something that would have helped.

What I would want checked before you spend anything

If your erections have changed, that change is information. It is worth understanding before it is treated, and certainly before it is treated with something experimental.

I would want to know whether the difficulty is there in every situation or only some. I would want your blood pressure, your fasting glucose, your cholesterol and a morning testosterone. In some men I would want a Doppler scan, to look at the blood flow directly.

That last one is not a formality. Erectile difficulty is sometimes the first sign of a vascular problem that matters well beyond the bedroom, and it can appear years before anything else does.

None of this is a preamble to selling you something. Quite often the answer is a tablet that costs very little, or a change that has nothing to do with the penis at all.

Where I have landed

If you want to try PRP, I would rather you did it inside a clinical trial. The protocol is scrutinised, the outcome is measured properly, and the cost is not yours.

If you have already had it and felt a benefit, I am not going to argue with your experience. Improvements seen after treatment are not always caused by the treatment itself. Sexual medicine is one of the fields where placebo responses can be substantial. But a real improvement is a real improvement, however it arrived.

And if you are about to spend a four-figure sum on a first course, my advice is to spend a fraction of it on finding out what is actually going on first. Whatever the eventual treatment turns out to be, understanding the problem comes first. That is the part I know adds value.

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