Sermorelin
What sermorelin is
Sermorelin is the first 29 amino acids of growth hormone releasing hormone. Natural GHRH is 44 amino acids long, and sermorelin reproduces the shortest fragment that retains full biological activity. Everything beyond residue 29 turns out not to be required for receptor binding.
That makes it the most conservative compound in the secretagogue group: not a novel analogue, just the working portion of a hormone the body already produces.
At a glance
| Class | GHRH (1-29) analogue |
|---|---|
| Target | GHRH receptor |
| Presentation | Lyophilised powder, or pre-filled SerenQ pen |
| Reported half-life | Approximately 10 to 20 minutes |
| Storage | 2 to 8 °C, refrigerated |
The shortest half-life here
At roughly ten to twenty minutes, sermorelin clears faster than anything else in this reference. Compare across the secretagogues:
| Compound | Receptor | Half-life |
|---|---|---|
| Sermorelin | GHRH | 10-20 minutes |
| CJC-1295 (no DAC) | GHRH | ~30 minutes |
| Ipamorelin | Ghrelin | ~2 hours |
| CJC-1295 (DAC) | GHRH | Several days |
| MK-677 | Ghrelin | ~24 hours |
A very short half-life is not a deficiency. It produces a defined pulse rather than a sustained elevation, which is the point when the research question concerns pulsatile release patterns rather than raising a baseline.
Sermorelin against CJC-1295
Both act at the same receptor, and they are frequently compared. Sermorelin is the natural GHRH(1-29) sequence. CJC-1295 is that sequence modified to resist enzymatic breakdown, which is why it lasts longer even in its no-DAC form. If you want the unmodified fragment, that is sermorelin.
Reconstitution
Room temperature first. Swab, draw the diluent, run it down the inside wall of the vial, and let it dissolve without agitation. Never shake. The solution should be clear and colourless.
Concentration is total peptide divided by diluent volume. Given the short half-life there is little reason to make up a large volume at once; time in solution is what degrades peptides. See the reconstitution guide for worked examples.
Storage
Sealed and lyophilised, 2 to 8 °C away from light. Reconstituted, keep refrigerated, upright and dark, and never freeze. Freeze-thaw cycles shear peptide chains invisibly.
The pre-filled SerenQ pen removes the reconstitution step entirely, arriving as a sealed made-up solution. Refrigerate it the same way and do not freeze it.
Frequently asked
Is sermorelin HGH? No. Growth hormone is a 191 amino acid protein given directly. Sermorelin is a 29 amino acid fragment that stimulates the body's own release instead.
Why only 29 amino acids when GHRH has 44? Because residues beyond 29 are not required for receptor activity. The shorter fragment is simpler to synthesise and behaves the same at the receptor.
Sermorelin or CJC-1295? Same receptor. Sermorelin is the unmodified natural fragment with a very short half-life; CJC-1295 is modified for longer duration.
Can it be combined with ipamorelin? They act on separate receptors, GHRH and ghrelin, so the combination is studied for complementary effect. Reconstitute separately.