The invention relates to an intra-dermally, sub-dermally or topically administrable growth factor concentrate derived from approximately 500 x106 to 1500 x106 human platelets per ml for treating hair loss. The concentrate comprises approximately 800 to 1200 pg/ml of Epidermal growth factor (EGF), 20 to SO pg/ml of Vascular Endothelial growth factor (VEGF), 15 to 30 pg/ml of Basic fibroblast growth factor (b-FGF), 30000 to 40000 pg/ml of Transforming growth factor-β (TGF- β) and 100000 to 200000 pg/ml of Platelet Derived growth factor-AB (PDGF-AB).