Comparison
Ipamorelin vs Tesamorelin
Ipamorelin vs tesamorelin: a ghrelin-receptor pentapeptide and a full-length stabilized GHRH analog. Receptor, structure and regulatory status. Research use only.
Side by side
| Specification | Ipamorelin | Tesamorelin |
|---|---|---|
| Category | Peptides | Peptides |
| Form | Lyophilized powder | Lyophilized powder |
| Fill amount | 10 mg | 5 mg |
| Molecular formula | C38H49N9O5 | C221H366N72O67S |
| Molecular weight | 711.9 g/mol | 5135.9 g/mol |
| CAS number | 170851-70-4 | 218949-48-5 |
| Research status | Investigational — never approved | FDA-approved ingredient (Egrifta, 2010) — one indication |
| Evidence levels | in-vitro, animal, clinical-trials | clinical-trials, approved-use |
| Cited sources | 4 | 6 |
Identifiers describe the compound as listed on each product page; see each page for the source of every value. Purity and testing results appear only on a published Certificate of Analysis.
What this comparison covers
Ipamorelin and tesamorelin both stimulate growth hormone release from the pituitary gland, but they come from opposite ends of peptide research: one is a five-amino-acid agonist of the ghrelin receptor that was never approved, the other a 44-amino-acid hormone analog that is the active ingredient of an approved medicine. This page sets them side by side.
It does not rank them, and it makes no statement about use, administration or outcomes. Every scientific claim below is drawn from the sources cited on the two product pages and listed at the end.
Shared ground
Both stimulate the pituitary's own growth hormone release rather than supplying growth hormone [1][3], and both are prohibited at all times in sport under the WADA Prohibited List [6].
Both are sold by Renuvia Labs as lyophilized powder for laboratory research use only, with verified identifiers on each product page and a lot Certificate of Analysis in the COA library once testing is complete.
How they differ
They use different receptors. Ipamorelin activates the growth hormone secretagogue receptor (GHS-R1a), the receptor for ghrelin [1]. Tesamorelin binds GHRH receptors, the receptors for growth hormone-releasing hormone [3].
They differ by an order of magnitude in size. Ipamorelin is five amino acids, several of them unnatural (711.9 g/mol). Tesamorelin is the full 44-amino-acid GHRH sequence with a trans-3-hexenoyl group on the first tyrosine (5135.9 g/mol).
Their regulatory status differs. Ipamorelin was never approved; its phase 2 trial in bowel-surgery patients found no significant difference from placebo [2], and FDA lists ipamorelin acetate among bulk substances that may present significant safety risks in compounding [5]. Tesamorelin is the active ingredient of Egrifta, approved in 2010 for one indication in adults with HIV and lipodystrophy, on the basis of phase 3 randomized trials [3][4]. Research-grade material of either is not an approved drug product.
Which research questions each is associated with
Ipamorelin appears in literature on selective growth hormone release: in rat and pig studies it released growth hormone without significantly raising ACTH or cortisol [1]. It also appears in research on ghrelin-like effects on gut movement after bowel surgery [2].
Tesamorelin appears in literature on HIV-associated lipodystrophy and liver fat in people with HIV, and on GHRH receptor signaling [3][4].
Questions researchers ask
- What is the difference between ipamorelin and tesamorelin?
- Ipamorelin is a five-amino-acid ghrelin-receptor (GHS-R1a) agonist that was never approved. Tesamorelin is a 44-amino-acid stabilized GHRH analog and the active ingredient of Egrifta. Both are studied for stimulating the pituitary's own growth hormone release, through different receptors.
- Which one has more clinical evidence?
- Tesamorelin, whose approval rests on phase 3 randomized trials in adults with HIV [4]. Ipamorelin's main published human efficacy trial, a phase 2 study in bowel surgery, found no significant difference from placebo [2]. More evidence for one indication is not evidence for any other use.
- What form are they supplied in?
- Both are lyophilized powder in a sealed, lot-numbered vial. The molecular data on each product page describe the free peptide, not the acetate salt.
- Are these products for human use?
- No. Both are sold for laboratory research use only by qualified researchers. They are not drugs, dietary supplements, cosmetics or foods.
Sources
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998
- Beck DE, et al. Proof-of-concept study of the ghrelin mimetic ipamorelin for postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014
- FDA / DailyMed. EGRIFTA SV (tesamorelin) prescribing information, Theratechnologies, revised December 2025
- Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med 2007
- FDA. Certain bulk drug substances for use in compounding that may present significant safety risks (updated April 2026)
- WADA. The 2026 Prohibited List, section S2.2.4 (copy published by JADCO)
For laboratory research use only by qualified researchers. Not for human or veterinary use. Not a drug, dietary supplement, cosmetic or food. Not evaluated by the FDA for any use.