Modified GRF 1-29 is a peptide that works to naturally increase the secretion of growth hormone (GH) in order to increase lean muscle mass and decrease overall body fat. Similar to naturally occurring growth hormone-releasing hormone (GHRH), modified GRF 1-29 binds to the GHRH receptor in order to increase the rate at which GH is secreted. In turn, when GH is secreted IGF-1 is released from the liver. The effects of modified GRF 1-29 are mediated by the negative feedback loop initiated by the endogenous hormone, somatostatin. This helps to avoid any negative side effects that could be caused by unregulated levels of GH secretion (https://peptide-guide.com/blogs/peptides/modified-grf-1-29).