How effective is platelet rich plasma in treating moderate hair loss? i am 40 years old and have thinning hair in crown area.

Jury's not out: The studies involving PRP for various types of hair loss ranging from androgenic alopecia to alopecia areata are all quite small but promising. Not unlike the early data for PRP and multiple orthopedic indications. Though like for many issues it may provide some limited benefit with very limited adverse effects, except on the wallet. Understand that there's even less long-term efficacy data!