Growth hormone research peptides

Releasing hormones, secretagogues and growth-axis factors — the thirteen compounds Amino Club supplies for somatotropic research, and how a GHRH analogue differs from a ghrelin mimetic.

Two pathways, not one

Growth hormone research peptides fall into two mechanistic families that are routinely conflated. The first is the growth hormone releasing hormone analogues — Sermorelin, Tesamorelin and the CJC-1295 series — which act at the GHRH receptor on the pituitary somatotroph and amplify the existing pulse.

The second is the ghrelin receptor agonists, or secretagogues: Ipamorelin, GHRP-2, Hexarelin and the orally active MK-677. These act at GHSR-1a, a different receptor entirely, and additionally suppress somatostatin tone. Because the two families act at separate receptors, they are frequently studied in combination — which is what the CJC-1295 / Ipamorelin preparation is for.

Downstream of both sits the effector arm: IGF-1 LR3, a long-arginine analogue with reduced binding-protein affinity, and the mechano growth factor splice variant supplied as MGF and its pegylated form PEG-MGF. Recombinant HGH 191AA is the full 191-residue sequence itself.

Choosing between the secretagogues

The practical distinction between the ghrelin agonists is selectivity. Ipamorelin is the most selective of the group, with minimal effect on cortisol and prolactin at research concentrations. GHRP-2 is more potent as a releaser but less clean in that respect, and Hexarelin is more potent again with correspondingly greater off-target activity and faster receptor desensitisation. Studies comparing them usually turn on that trade-off rather than on raw potency, which is set out in detail on the Ipamorelin versus GHRP-2 comparison.

Within the GHRH analogues, the split that matters is the drug affinity complex. CJC-1295 with and without DAC are the same core sequence with very different half-lives, and the choice between the DAC form and the non-DAC form changes the shape of the release profile rather than its magnitude. Tesamorelin is a stabilised GHRH analogue studied specifically in the context of visceral adipose tissue.

The complete group with current strengths sits on the growth and recovery category page.

Purity, presentation and handling

Each compound in this group is specified at 99% purity or better by HPLC with identity confirmed by mass spectrometry, and is released only against the Certificate of Analysis for its own batch. The batch number on that certificate matches the one printed on the vial. The lab testing page documents the quarantine and release sequence.

This group is supplied lyophilised. Post-reconstitution stability differs sharply across it: the short secretagogue sequences and the much larger recombinant proteins do not behave alike, and IGF-1 LR3 in particular has handling requirements that do not generalise from the rest of the group. Those notes sit on each product page rather than as a single instruction. Reconstitution consumables are listed under lab supplies.

Compound guides in this group

Individual guides to the compounds in this group.

CJC-1295 — a GHRH analogue substituted at four positions to resist degradation.
Sermorelin — GRF(1-29), the shortest GHRH sequence that still activates the receptor.
Tesamorelin — full-length GHRH shielded by a single fatty acid group.
Ipamorelin — the most selective of the ghrelin receptor secretagogues.
GHRP-2 — more potent than ipamorelin, and far less selective.
Hexarelin — a secretagogue that also binds CD36.
MK-677 — orally active, and sustained rather than pulsatile.
HGH 191AA — the full somatropin sequence, which bypasses the pituitary.
IGF-1 LR3 — the growth factor itself, modified to escape its binding proteins.
MGF — a splice variant of IGF-1, not an analogue of it.
PEG-MGF — what pegylation buys, and what it costs.

Research use only

All growth hormone research peptides listed here are laboratory reference materials. They are not medicines, not supplements, and not for human or veterinary use, and no dosing guidance or administration protocol is provided for any of them. The full terms are in the research use policy.