Extraordinary claims require extraordinary evidence. I think it's appropriate to utilize skeptical thinking in the face of claims that cosmetically significant results were achieved in a two-week period.
I don't think the skeptics should be shouted down by the positive-thinkers...after all, the list of ineffective hair-loss treatments is very long, and the list of successes, vanishingly short.
I, for one, greet with raised eyebrow the hypothesis that there is a mechanism by which PRP can cause sufficient thickening of a hair shaft within two weeks so as to create a visible effect. Hair grows, what, a quarter of an inch in that time? The claim challenges credulity--I think more work needs to be done. For instance, I'd like to see direct evidence of hair-shaft thickening High magnification photos of the hair root, two-weeks apart, would reveal this sort of dramatic growth, no?
Of course, I'm not a doctor. Dr. Feller seems enthused by the procedure, and I have been given no reason to question his motives. So I am warily interested in these developments. I would even consider the treatment myself, if I can be convinced that the risk/reward ratio tilts far enough in the right direction.