Tesamorelin vs Ipamorelin: What’s the Difference?
Tesamorelin and ipamorelin both make the pituitary release growth hormone in published studies, but they act on different receptors and are very different molecules.
Tesamorelin is a 44-amino-acid analogue of human growth hormone-releasing hormone (GHRH) with a trans-3-hexenoyl group on its first residue. It acts on the GHRH receptor, and it is the active ingredient of an FDA-approved drug (Egrifta).
Ipamorelin is a 5-residue synthetic peptide, Aib-His-D-2-Nal-D-Phe-Lys-NH2, developed by Novo Nordisk. It acts on the growth hormone secretagogue receptor (GHS-R1a, the ghrelin receptor) and has never been approved as a medicine.
In short: tesamorelin works through the GHRH pathway, ipamorelin through the ghrelin pathway. CJC-1295 and sermorelin sit on tesamorelin's side of that line.
Tesamorelin vs Ipamorelin at a Glance
Tesamorelin is a 44-residue GHRH analogue (C221H366N72O67S, 5,135.9 Da free base per the FDA label). Ipamorelin is a 5-residue ghrelin-receptor agonist (C38H49N9O5, 711.9 g/mol). Tesamorelin is the active ingredient of an FDA-approved drug; ipamorelin has no FDA approval.
| Comparison | Tesamorelin | Ipamorelin |
|---|---|---|
| Peptide length | 44 amino acids + N-terminal hexenoyl | 5 amino acids |
| Molecular weight | 5,135.9 g/mol | 711.9 g/mol |
| Sequence | Hex-YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL-NH2 | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Molecular relationship | Modified full-length GHRH(1-44) | Synthetic GHRP-class pentapeptide |
| Main research focus | GHRH receptor, endogenous GH and IGF-1 | Ghrelin receptor (GHS-R1a), selective GH release |
| Research evidence | Phase 3 trials, FDA-approved drug | Animal pharmacology, phase 1 and 2 trials |
| FDA-approved drug component | Yes (Egrifta, 2010) | No |
What are Tesamorelin and Ipamorelin
44 AA
Tesamorelin
A 44-residue GHRH analogue with a trans-3-hexenoyl group on Tyr1 that makes it resistant to dipeptidyl aminopeptidase-IV.
Research areas
GHRH receptor • GH pulsatility • IGF-1 • Visceral and liver fat in HIV
The FDA label describes tesamorelin as binding and stimulating human GRF receptors with potency similar to endogenous GRF. Its mean elimination half-life after a single subcutaneous dose was 8 to 11 minutes in healthy subjects.
Explore Tesamorelin5 AA
Ipamorelin
A 5-residue ghrelin-receptor agonist from Novo Nordisk, described in 1998 as the first selective growth hormone secretagogue.
Research areas
GHS-R1a • GH release • Bone growth in rats • Postoperative ileus
In swine, ipamorelin released GH without raising ACTH or cortisol beyond GHRH-like levels, even at doses far above its GH ED50, unlike GHRP-6 and GHRP-2. Its terminal half-life after intravenous infusion in healthy men was 2 hours.
Key Differences Between Tesamorelin and Ipamorelin
| Key differences | Tesamorelin | Ipamorelin |
|---|---|---|
| Receptor | GHRH receptor (GHRHR) on pituitary somatotrophs, the same receptor as native GHRH, sermorelin and CJC-1295. |
Growth hormone secretagogue receptor type 1a (GHS-R1a), the ghrelin receptor, the same receptor as GHRP-2 and GHRP-6. |
| Structure | 44 residues: the full human GHRH(1-44) sequence, trans-3-hexenoyl on Tyr1, C-terminal amide. |
5 residues with non-proteinogenic Aib and D-2-naphthylalanine, plus D-Phe and a C-terminal lysinamide. |
| Selectivity | Acts through the physiological GHRH pathway; in 13 healthy men it increased mean overnight GH and GH peak area. |
Released GH in swine without the ACTH and cortisol rise seen with GHRP-6 and GHRP-2. |
| Published half-life | 8 to 11 minutes after a single subcutaneous dose (FDA labels). |
2 hours after a 15-minute intravenous infusion in healthy men. |
| Clinical programme | Phase 3 trials in HIV-associated abdominal fat, published in NEJM (2007) and JCEM (2010). |
Phase 2 trials for postoperative ileus; the published trial found no significant difference from placebo. |
| Regulatory status | FDA-approved since 10 November 2010 as Egrifta for a specific HIV-related indication. |
Not FDA-approved. FDA's compounding page lists ipamorelin acetate in its safety-risk category. |
How their research profiles differ
- Tesamorelin
- 44-AA modified GHRH
- GHRH receptor
- GH and IGF-1 research
- Ipamorelin
- 5-AA GHRP-class peptide
- Ghrelin receptor (GHS-R1a)
- Selective GH-release research
Tesamorelin vs Ipamorelin: Which Is Better?
Neither is better in general, because they answer different research questions. No published trial has compared the two head to head.
Tesamorelin is the better-characterised molecule clinically: it has randomised phase 3 trials and an FDA label. Ipamorelin's literature is mostly animal pharmacology, a human pharmacokinetic study and phase 2 trials in postoperative ileus.
The deciding question is the pathway. Work on the GHRH receptor points to tesamorelin, sermorelin or CJC-1295. Work on the ghrelin receptor and selective GH secretagogues points to ipamorelin.
Does the model need to stimulate the GHRH receptor, or the ghrelin receptor (GHS-R1a)?
Can Tesamorelin and Ipamorelin Be Studied Together?
GHRH and ghrelin-receptor agonists act on two separate stimulatory pathways for GH release, and published work has looked at the two classes together: Veldhuis et al. (2009) studied simultaneous GHRH and GHRP-2 infusion in 47 men, and Fintini et al. (2005) combined a GHRH analogue with GHRP-2 in GHRH-knockout mice.
Neither study used tesamorelin or ipamorelin, and we found no published study of that specific pairing. A design that compares the two should keep separate experimental groups so each compound's effect can be attributed.
There Isn’t One Universal “Winner”
Tesamorelin
GHRH-receptor research profile
44 AA • GHRHR • FDA-approved molecule
Ipamorelin
Ghrelin-receptor research profile
5 AA • GHS-R1a • selective GH secretagogue
Compare the Research. Verify the Material.
Clean Peptide stocks tesamorelin in 5 mg and 10 mg. Each size has its own lot, analysed by ILS Laboratories: HPLC purity, net peptide content and identity by HPLC retention time against a reference standard, all on the product page.
We do not stock ipamorelin at the moment. Its identity, structure and published research are summarised in our ipamorelin guide.
Research use only
Identity
verified
Purity
verified
Tested
in USA
Question
Frequently Asked
What is the difference between tesamorelin and ipamorelin?
Tesamorelin is a 44-residue GHRH analogue that acts on the GHRH receptor. Ipamorelin is a 5-residue ghrelin-receptor (GHS-R1a) agonist. They reach growth hormone release through different receptors.
Is tesamorelin a GHRH analogue or a GHRP?
A GHRH analogue. Its sequence is the full 44 residues of human GHRH with a trans-3-hexenoyl group on the first tyrosine.
Is ipamorelin a GHRP?
Ipamorelin belongs to the GHRP class of growth hormone secretagogues. Raun et al. (1998) described it as the first selective growth hormone secretagogue.
Which has the longer half-life, tesamorelin or ipamorelin?
In published human data, ipamorelin's terminal half-life was 2 hours after intravenous infusion, and tesamorelin's mean elimination half-life was 8 to 11 minutes after a subcutaneous dose.
How does CJC-1295 compare with tesamorelin and ipamorelin?
CJC-1295 is a modified GHRH(1-29) analogue, so it works on tesamorelin's receptor, not ipamorelin's. The original CJC-1295 carries a maleimide (DAC) that binds albumin; published human data gave it a half-life of 5.8 to 8.1 days.
Is tesamorelin FDA-approved?
Yes. Tesamorelin has been FDA-approved since 2010 as Egrifta for a specific HIV-related indication. Tesamorelin sold as a research material is not that approved product.
Is ipamorelin FDA-approved?
No. Ipamorelin has never been approved by FDA, and FDA's compounding page lists ipamorelin acetate in its safety-risk category.
Does Clean Peptide sell ipamorelin?
Not at the moment. We stock tesamorelin in 5 mg and 10 mg with a per-lot ILS Laboratories certificate.
Research Peptides. Documented by Batch.
Every size in the catalogue ships against the certificate issued for its own lot.
For laboratory research use only. Not for human or veterinary use.
References
Identity data come from the FDA labels, the FDA substance registry (GSRS) and PubChem. Study findings are paraphrased from the PubMed abstracts.
- FDA label EGRIFTA SV (tesamorelin) for injection Structure, molecular weight, mechanism and half-life of tesamorelin.
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue European Journal of Endocrinology, 1998. Discovery, receptor profile and selectivity in swine.
- Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers Pharmaceutical Research, 1999. Terminal half-life of 2 hours.
- Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV New England Journal of Medicine, 2007. Phase 3 trial of tesamorelin, 412 patients.
- Stanley TL, et al. Effects of a growth hormone-releasing hormone analog on endogenous GH pulsatility and insulin sensitivity in healthy men Journal of Clinical Endocrinology and Metabolism, 2011. Tesamorelin and GH pulsatility in 13 men.
- Beck DE, et al. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients International Journal of Colorectal Disease, 2014. Phase 2, NCT00672074.
- Teichman SL, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults Journal of Clinical Endocrinology and Metabolism, 2006. CJC-1295 (DAC) half-life of 5.8 to 8.1 days.
- Veldhuis JD, et al. Determinants of GH-releasing hormone and GH-releasing peptide synergy in men GHRH and GHRP-2 infused together in 47 men, 2009.
- PubChem Ipamorelin, CID 9831659 Formula, molecular weight and CAS 170851-70-4.
