What is ipamorelin?
Ipamorelin is a synthetic pentapeptide growth hormone secretagogue: Aib-His-D-2-Nal-D-Phe-Lys-NH2. It was described in 1998 as the first selective member of its class, releasing growth hormone through a secretagogue receptor rather than the growth hormone releasing factor receptor (Raun et al., 1998).
The endogenous ligand of that receptor was identified a year later as ghrelin, an acylated peptide from the stomach (Kojima et al., 1999). Ipamorelin has been studied in cell culture, rats, swine and human pharmacology and clinical trials. Disguised Alpha supplies it as a lyophilized powder for laboratory research use only. Nothing on this page is guidance for use in people.
Ipamorelin reference data
| Property | Value |
|---|---|
| Name | Ipamorelin |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 (two non-natural residues and two D-amino acids) |
| Peptide class | Growth hormone secretagogue, synthetic pentapeptide |
| Molecular formula | C38H49N9O5 |
| Molecular weight | 711.86 g/mol |
| CAS number | 170851-70-4 (PubChem CID 9831659) |
| Form | Lyophilized powder |
| Testing | Third-party tested, with the certificate for each lot published on the product page and in the COA portal |
Formula, molecular weight and CAS number are from the Ipamorelin product page; the sequence is from PubChem. Because ipamorelin holds non-natural residues, it is not a fragment of any human protein. Confirm identity and measured content against your lot's certificate.
What the research covers
Published work on ipamorelin falls into five areas. Each summary below states the model used.
Selectivity in the founding study
Ipamorelin was identified within a series that removed the central Ala-Trp dipeptide of an earlier secretagogue. In primary rat pituitary cells it released growth hormone with potency similar to GHRP-6, and antagonist profiling placed its action at a secretagogue-like receptor rather than the releasing factor receptor.
It released growth hormone in rats and in conscious swine. The result that defined it was a negative one: in swine it did not raise ACTH or cortisol above the levels seen with the releasing factor, while GHRP-6 and GHRP-2 both did (Raun et al., 1998). Models: rat cell culture, rats and swine.
Two receptors, two mechanisms
The secretagogue class and the releasing factor act through separate pathways. In rat primary pituitary cell culture, a hexapeptide secretagogue and the releasing factor produced a synergistic effect on growth hormone release at maximal concentrations; the secretagogue alone did not raise intracellular cyclic AMP while the releasing factor raised it roughly three fold, and the two did not cross-desensitize (Cheng et al., 1989). That finding, made with an earlier secretagogue, is the cell-culture basis for research designs that pair the two classes. Model: rat cell culture.
Longitudinal bone growth in rats
In adult female rats, ipamorelin produced a concentration-related increase in longitudinal growth rate measured by tetracycline labelling in the proximal tibia, from 42 to 52 micrometres per day, with no change in total IGF-I or in serum markers of bone turnover (Johansen et al., 1999). Model: rat.
Human pharmacokinetics
A study at five escalating levels in healthy male volunteers reported kinetics proportional to the amount given, a terminal half-life of about two hours, and a single episode of growth hormone release peaking near 40 minutes (Gobburu et al., 1999). Model: healthy human volunteers.
A completed clinical trial
Ipamorelin is one of the few compounds in its class with a finished randomized controlled trial. In a double-blind, placebo-controlled phase 2 study in 114 adults after bowel resection, it was well tolerated but produced no significant difference from placebo in time to tolerance of a standardized solid meal, 25.3 hours against 32.6 (Beck et al., 2014). Ipamorelin is not an approved drug. Model: phase 2 clinical trial.
Key studies
- Raun K, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998. PMID 9849822. Rat pituitary cells, rats and swine: potency, receptor profile and ACTH/cortisol selectivity.
- Kojima M, et al. "Ghrelin is a growth-hormone-releasing acylated peptide from stomach." Nature. 1999. PMID 10604470. Identification of the endogenous ligand of the secretagogue receptor.
- Cheng K, et al. Endocrinology. 1989. PMID 2541999. Rat pituitary cell culture: secretagogue and releasing factor synergy, cyclic AMP.
- Johansen PB, et al. Growth Horm IGF Res. 1999. PMID 10373343. Adult female rats: longitudinal bone growth by tetracycline labelling.
- Gobburu JV, et al. Pharm Res. 1999. PMID 10496658. Healthy male volunteers: pharmacokinetic and pharmacodynamic modeling.
- Beck DE, et al. Int J Colorectal Dis. 2014. PMID 25331030. Randomized, placebo-controlled phase 2 trial after bowel resection.
Handling and storage of lyophilized ipamorelin
General laboratory practice for this material:
- Store the lyophilized powder at -20°C, protected from light, until use (storage guidance on the product page).
- Let the sealed vial reach room temperature before opening so moisture does not condense on the powder.
- Reconstitute in a sterile solvent or buffer suited to the assay, adding it gently down the vial wall and letting the powder dissolve rather than shaking it.
- Ipamorelin is a capped pentapeptide, sturdier than long-chain peptides, but no more tolerant of freeze/thaw cycles. After reconstitution keep solutions at 2 to 8°C and protected from light, and split stock into single-use aliquots.
- Record the lot number and take the molecular weight for molarity from the certificate.
Frequently asked questions
What is ipamorelin?
Ipamorelin is a synthetic five-residue growth hormone secretagogue that acts at the receptor whose natural ligand is ghrelin (Raun et al., 1998; Kojima et al., 1999).
Is ipamorelin a peptide?
Yes. It is a pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, built partly from non-natural amino acids, so it is synthetic rather than a piece of a human protein.
Ipamorelin vs CJC-1295: what is the difference?
They act on different receptors and on different timescales. Ipamorelin acts at the secretagogue receptor with a reported terminal half-life of about two hours in volunteers (Gobburu et al., 1999); CJC-1295 is a releasing factor analog acting at the releasing factor receptor. Our CJC-1295 vs Ipamorelin comparison sets the data side by side.
Is ipamorelin an approved drug?
No. It reached a phase 2 trial after bowel resection, which found no significant difference from placebo on its primary endpoint (Beck et al., 2014). Disguised Alpha sells it strictly for laboratory research.
How should ipamorelin powder be stored?
Keep the lyophilized powder at -20°C and protected from light. After reconstitution, store the solution at 2 to 8°C, protected from light, and avoid freeze/thaw cycles.
Where can researchers buy ipamorelin?
Disguised Alpha sells it for laboratory research, third-party tested with the certificate published on the product page: Ipamorelin.
Related compounds and guides
- CJC-1295 vs Ipamorelin: research comparison
- CJC-1295 No DAC research guide
- CJC-1295 No DAC & Ipamorelin
- Tesamorelin research guide
- COA portal: every published certificate, by lot
This product is for research use only. It has not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.