YES, in some cases, you can see improvement in existing hair density. But NO NEW MATURE hairs will grow with PRP. This improvement in density is due to thickening of existing hair shafts. 100 hairs mimic like 120 hairs as their shaft diameter increases. But once you stop PRP, it gets back to same old state. PRP definitely has good role in controlling hairloss, but it cannot grow any new hairs for a bald person. For diffuse pattern hair loss, PRP can be used as a substitute.