Sermorelin mastery course
Unit 4 of 11

The GH and IGF-1 axis

A GH pulse is only the middle of a longer story. Growth hormone travels to the liver, drives IGF-1, and then IGF-1 and…

From a pituitary pulse to IGF-1, and back again through feedback

A GH pulse is only the middle of a longer story. Growth hormone travels to the liver, drives IGF-1, and then IGF-1 and GH themselves feed back on the hypothalamus and pituitary to keep the whole system in bounds.

This unit maps the axis across the body, follows GH to IGF-1, unpacks the feedback loops that make sermorelin self-limiting, and shows why the biggest natural pulse is tied to slow-wave sleep.

Key terms

The axis, across the body


The biggest pulse is at sleep onset


From GH pulses to a steadier IGF-1


The feedback loops that self-limit


Why intact feedback matters