Every few weeks a man sits down and tells me he is thinking about platelet-rich plasma (PRP) injections into the penis. He has usually read that the treatment 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.