IGF-1 is a biomarker associated with protein intake and is part of the growth hormone and mTOR pathways.

“by convention we use igf-1 as a biomarker for protein intake yeah and uh it's certainly associated with protein intake but you want to tell people what igf-1 is you know a little bit of background of you know where it comes from and what it's a proxy for sure so igf-1 is insulin-like growth factor one um it's uh a hormone that's in in the growth hormone pathway so when so it's you can think of as a growth promoting hormones are sort of part of this central pathway that um promotes uh growth in many many different tissues so if you have high growth hormone levels you'll have high igf-1 levels and that in high m tour right so this is a this is a a part of the mtor pathway as well upstream of mtor”