Ipamorelin vs Sermorelin

Different receptors, different classes

Ipamorelin is a synthetic pentapeptide acting at the ghrelin receptor (GHSR-1a). Compounds in that class are called growth hormone secretagogues.

Sermorelin is a GHRH analogue — it corresponds to the first 29 residues of growth hormone-releasing hormone and acts at the GHRH receptor. A different receptor, on the same cells.

That is the entire answer to the comparison, and it is a mechanistic difference rather than a matter of degree. Asking which of the two is better is asking which of two different receptors is better, which is not a question a compound can answer.

Sermorelin's counterpart in our range is CJC-1295

This is the practically useful part. If sermorelin is in your comparison because you want a GHRH analogue, ipamorelin is not the compound to weigh it against — ipamorelin is in the other class entirely.

The GHRH analogues in our range are CJC-1295 DAC and the no-DAC form, which is the CJC component of our CJC-1295 + Ipamorelin blend and is also listed as mod GRF (1-29). That last synonym is the giveaway: GRF (1-29) and sermorelin describe the same 29-residue span of GHRH. The no-DAC CJC is the closer structural neighbour of sermorelin, and CJC-1295 DAC vs no DAC explains what the DAC modification changes.

Side by side

What the ipamorelin literature reports

Ipamorelin's defining study is its original characterisation, which is also where its name in the literature comes from: "the first selective growth hormone secretagogue" (PMID 9849822). It is animal and in-vitro work, and what it reported was selectivity — growth hormone release without a meaningful increase in cortisol, ACTH or prolactin at GH-releasing doses. That selectivity is the property that distinguished it from the earlier growth hormone-releasing peptides.

That is one characterisation study from 1998, in animals and cells. It is a narrower record than it is often made to sound, and the honest framing is that ipamorelin is well characterised mechanistically and thin on human data.

What we hold on sermorelin

Sermorelin has been marketed as a licensed medicine in some jurisdictions, under the name Geref. It is not in the Peptiq range and we hold no evidence file on it.

Sermorelin is not in the Peptiq range. It is described here because the comparison is asked for, and the description is limited to published chemistry and regulatory status — we do not hold an evidence file on a compound we do not supply.

The related comparison

The same receptor split appears again between ipamorelin and tesamorelin, and that one is more useful because both compounds are in our range and the evidence asymmetry between them is large. See ipamorelin vs tesamorelin.

Supply note. Peptiq supplies research compounds for laboratory research use only. We are not a pharmacy and we do not supply licensed medicines. Where a licensed medicine is named on this page it is named to draw a distinction, not because we sell it, and nothing here is guidance on use.