And yo, you were going on about how IGF-1 is not in the scalp only in plasma GET THIS - the majority of IGF-1 distributed to tissues is from plasma. 25. Breier BH, Gluckman PD: The regulation of postnatal growth: nutritional influences on endocrine pathways and function of the somatotrophic axis. Livest Prod Sci 1991;27:77-94. So yeah, all those dudes with vertex balding HAD HIGH IGF-1 in THE SCALP!!