Ipamorelin vs Tesamorelin
Quick Answer
Ipamorelin and Tesamorelin act on different receptors. Ipamorelin is a selective ghrelin / GH-secretagogue receptor (GHS-R) agonist; Tesamorelin is a GHRH-receptor analog. In research they target two distinct arms of GH secretion, which is why they are sometimes studied in combination rather than as substitutes. Both are ≥99% HPLC-verified at Peptide.Express for in-vitro research only.
Ipamorelin vs Tesamorelin: At a Glance
| Attribute | Ipamorelin | Tesamorelin |
|---|---|---|
| Receptor target | Ghrelin / GHS-R | GHRH receptor |
| Mechanism class | Selective GHSR-1a agonist | Full-length stabilized GHRH analog |
| Peptide length | 5 amino acids (pentapeptide) | 44 amino acids |
| CAS number | 170851-70-4 | 218949-48-5 |
| Molecular weight | ~711.9 Da | ~5135.9 Da |
| Selectivity note | Minimal effect on cortisol/prolactin in studies | GHRH-pathway specific |
| Purity (Peptide.Express) | ≥99% HPLC verified | ≥99% HPLC verified |
How Ipamorelin and Tesamorelin Differ in Research
Ipamorelin and Tesamorelin are often compared, but they are not interchangeable: they act on different receptors. Ipamorelin is a small, selective ghrelin-receptor (GHS-R) agonist, while Tesamorelin is a GHRH-receptor analog. They represent the two complementary signaling arms of growth-hormone secretion studied in the somatotropic axis.
Because of this complementarity, research designs sometimes investigate a GHRH analog and a ghrelin agonist together rather than choosing between them. Ipamorelin is noted in the literature for its selectivity relative to older secretagogues. Tesamorelin, by contrast, is a longer stabilized GHRH analog.
Peptide.Express supplies both at ≥99% HPLC-verified purity with a Certificate of Analysis. All compounds are for in-vitro laboratory research use only.
Frequently Asked Questions
Do Ipamorelin and Tesamorelin work the same way?
No. Ipamorelin is a ghrelin / GHS-R agonist and Tesamorelin is a GHRH-receptor analog. They act on different receptors and are studied as complementary, not equivalent, research compounds.
Can Ipamorelin and Tesamorelin be studied together?
In research models a GHRH analog and a ghrelin agonist are sometimes combined to investigate both arms of GH secretion. Note: CJC-1295 (No DAC) is the GHRH analog most commonly paired with Ipamorelin. For laboratory research use only.
Which is more selective?
Ipamorelin is frequently cited for its selectivity as a GH secretagogue with minimal off-target effects in study models, relative to earlier-generation compounds.
References
- Raun K, et al. "Ipamorelin, the First Selective Growth Hormone Secretagogue." European Journal of Endocrinology, 1998. Read the Raun ipamorelin selectivity study on PubMed
- Smith RG, et al. "Modulation of Pulsatile GH Release Through a Novel Receptor in Hypothalamus and Pituitary Gland." Recent Progress in Hormone Research, 1996. Read the GH secretagogue receptor and phospholipase C signaling review on PubMed
- Bowers CY, Momany FA, Reynolds GA, Hong A. "On the In Vitro and In Vivo Activity of a New Synthetic Hexapeptide That Acts on the Pituitary to Specifically Release Growth Hormone." Endocrinology, 1984. Read the founding Bowers GHRP hexapeptide study on PubMed
- Falutz J, et al. "Long-term safety and effects of tesamorelin, a growth hormone-releasing factor analogue, in HIV-infected patients with abdominal fat accumulation." AIDS, 2008. Read the tesamorelin long-term safety study on PubMed
- Falutz J, et al. "Tesamorelin Improves Fat Quality Independent of Changes in Fat Quantity." AIDS, 2021. Read the tesamorelin fat quality analysis on PMC
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury — Tesamorelin. National Institute of Diabetes and Digestive and Kidney Diseases, NIH Bookshelf. Read the LiverTox tesamorelin monograph on NCBI Bookshelf
- Egrifta (tesamorelin for injection) FDA prescribing information, 2024. The authoritative source for the approved indication, pharmacokinetic parameters and monitored laboratory values. Read the Egrifta FDA prescribing information (PDF)