For research purposes only. This comparison describes the chemical identity and research context of Ipamorelin and Sermorelin. It is not medical advice, does not rank the compounds for any purpose, and does not describe any effect, dose, or use in humans or animals.
Ipamorelin vs Sermorelin at a glance
| Attribute | Ipamorelin | Sermorelin |
| Class | Synthetic pentapeptide (GHS) | GHRH (1-29) analogue |
| Length | 5 aa | 29 aa |
| Approx. molecular weight | ~711.9 g/mol | ~3358 g/mol |
| Receptor / target (research) | Ghrelin / GHS receptor | GHRH receptor |
| CAS number | 170851-70-4 | 86168-78-7 |
What is Ipamorelin?
Ipamorelin is a synthetic pentapeptide (five amino acids) with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2. In research literature it is described as a selective ghrelin / growth-hormone-secretagogue receptor ligand. It is supplied as a lyophilised powder for laboratory research.
Read more in our Ipamorelin research guide, or view the Ipamorelin product page.
What is Sermorelin?
Sermorelin is a synthetic peptide corresponding to the first 29 amino acids of growth hormone-releasing hormone (GHRH 1-29), the N-terminal fragment of GHRH. It is supplied as a lyophilised powder for laboratory research.
Read more in our Sermorelin research guide, or view the Sermorelin product page.
Key differences
The defining difference is receptor class. Sermorelin is a GHRH-receptor analogue — the 29-amino-acid N-terminal fragment (GHRH 1-29) of growth hormone-releasing hormone. Ipamorelin is a much smaller five-amino-acid ligand of the ghrelin / growth-hormone-secretagogue (GHS) receptor. They engage two different receptors within the growth-hormone axis and differ greatly in size (29 vs 5 residues) and molecular weight (~3358 vs ~711.9 g/mol).
How researchers distinguish Ipamorelin and Sermorelin
In research the two are often studied side by side precisely because they represent the two principal receptor families in this area: the GHRH receptor and the ghrelin / GHS receptor. A study's choice between them is an experimental-design decision driven by which receptor pathway is under investigation — it is not a question of relative potency for any applied or human purpose, and nothing here should be read as such.
Frequently asked questions
No. They are chemically distinct peptides that act on different receptors: sermorelin is a 29-amino-acid GHRH-receptor analogue, while ipamorelin is a 5-amino-acid ghrelin / GHS-receptor ligand.
Receptor class and size. Sermorelin targets the GHRH receptor and is 29 amino acids; ipamorelin targets the ghrelin / GHS receptor and is 5 amino acids.
Yes — in growth-hormone-axis research they are sometimes used together as representatives of the two main receptor families (GHRH vs GHS). This is an experimental-design choice, not guidance for any human use.
Both are available from PurePeptides at greater than 99% purity as lyophilised powders, with same-day dispatch before 3PM and tracked UK & EU delivery. They are sold strictly for laboratory research use only.
Research-grade Ipamorelin & Sermorelin
Greater than 99% purity, lyophilised powder, same-day dispatch before 3PM with tracked UK & EU delivery. Research use only.
Buy Ipamorelin → Buy Sermorelin →Disclaimer: All products supplied by PurePeptides are strictly for laboratory research use only. They are not for human or animal consumption and are not medical products. This comparison is informational and summarises publicly available research; it is not medical, clinical, or dosing advice.