Growth Hormone & Secretagogues

The growth-hormone axis has three useful research entry points: replace GH directly, stimulate the pituitary with a GHRH analog, or stimulate it with a ghrelin-receptor agonist. Each approach produces a different pulse shape, feedback profile, and IGF-1 response, which is why the category includes recombinant hormone, GHRH analogs, ghrelin mimetics, and the downstream IGF-1 analog.

What the research covers

Recombinant HGH binds the GH receptor directly, activating JAK/STAT signalling and increasing hepatic and local IGF-1. It is used to study longitudinal bone growth, nitrogen balance, lipolysis, and body composition. Because it bypasses pituitary feedback, GH and IGF-1 must be monitored together.

Sermorelin is a 29-amino-acid GHRH analog that binds the GHRH receptor on somatotrophs and stimulates pulsatile GH release. Tesamorelin is a stabilised 44-amino-acid GHRH analog with a trans-3-hexenoyl group that resists DPP-4 cleavage; it is studied for visceral-fat reduction. Ipamorelin is a selective ghrelin-receptor agonist that releases GH with minimal cortisol or prolactin effect. The IPA/CJC-1295 blend pairs ipamorelin with a long-acting GHRH analog to amplify the pulse.

IGF-1 LR3 is a long-acting IGF-1 analog with reduced binding-protein affinity. It activates the IGF-1 receptor and downstream PI3K/Akt and MAPK pathways, making it a tool for muscle protein synthesis, cell proliferation, and tissue repair studies.

How to choose

If the question is downstream GH action, use recombinant HGH. If the question is pituitary reserve or pulsatility, use sermorelin or tesamorelin. If the question is ghrelin-receptor selectivity, use ipamorelin. If the question is combined GHRH and ghrelin activation, use the IPA/CJC-1295 blend. If the question is IGF-1 receptor signalling independent of GH, use IGF-1 LR3.

Documentation and handling

HGH is a large protein; freeze-thaw damage and aggregation are the main sources of variability. Reconstitute gently, do not shake, and store at 2-8C after reconstitution. Peptide secretagogues follow standard lyophilised storage at -20C.

FAQ

Does a secretagogue raise GH the same way as HGH? No. Secretagogues act upstream and preserve pulsatility; HGH replaces the hormone directly.

Why measure IGF-1? GH acts partly through IGF-1, so changes in GH without IGF-1 data are incomplete.

Is tesamorelin the same as sermorelin? No. They are different GHRH analogs with different stability and clinical research histories.