The way it was explained to me was pretty simple. PRP, when performed correctly, has the same effect as finasteride. It doesn't create new hair growth, it simply thickens existing hairs that have miniaturized to varying degrees. It isn't a permanent solution but different clinics will have different ideas as to how often patients need top ups. Some will say up to two years, others will say three times in the first year and then wait for a few years before another round.
It can be maddening, really, but in the end it comes down to documented evidence of efficacy. If someone says it works, have them show you the evidence, and not just one or two examples, either. If you can speak to someone that's had it, that's the best route but in the end it really comes down to who seems to be the most credible, on top of the evidence presented. I've had it myself and I know I had a small but positive effect and I've seen some impressive turnarounds via photographic documentation.
