Growth hormone, released from the pituitary in pulses, functions largely as a trigger signal within the broader axis. While it does act directly on some tissues, much of its documented biological significance comes from what it sets in motion downstream rather than direct action alone.
This trigger role is why measuring GH itself is clinically tricky — its pulsatile, unpredictable pattern throughout the day makes a single measurement a poor indicator of overall axis activity.
When growth hormone reaches the liver, it binds receptors that prompt hepatic cells to synthesize and release insulin-like growth factor 1 (IGF-1), sometimes called somatomedin C in older literature, into circulation.
IGF-1 then travels to tissues throughout the body — bone, muscle, and cartilage among them — promoting cell growth and proliferation, effects that were historically attributed to HGH directly before this two-step mechanism was fully characterized in the research literature.
Because IGF-1 has a much longer half-life and stays comparatively stable across the day, unlike pulsatile GH, it provides a far more reliable averaged readout of growth hormone axis activity over time, which is why clinicians measure IGF-1, not GH itself, as the standard screening test.
This is also why research and clinical discussions of "growth hormone status" almost always reference IGF-1 levels rather than attempting to characterize GH secretion directly through repeated sampling.
The GH-IGF-1 relationship is also regulated by negative feedback: elevated IGF-1 signals back to the hypothalamus and pituitary to reduce further GH release, keeping the axis in balance under normal physiology.
This explains the biological mechanism only; it is not a comparison of specific compounds sold commercially or a usage guide. Neither HGH nor IGF-1-related research peptides are part of REVIVE LAB UAE's catalog, and this article makes no product or purchase claim.