Published · 8 references
Ipamorelin vs Tesamorelin
Ipamorelin and Tesamorelin are different molecules: Ipamorelin is a synthetic five-residue peptide, and Tesamorelin is a synthetic 44-residue analog of human growth hormone-releasing hormone.
Structure at a glance
Ipamorelin · 5 residues
Tesamorelin · 44 residues
Hex: N-terminal trans-3-hexenoyl group. NH2: C-terminal amide. A raised D marks a D-amino acid. 2Nal: 2-naphthylalanine. Aib: alpha-aminoisobutyric acid. Codes are three-letter amino acid codes.
Drawn from the product database. Each measure's bars share one scale.
| Property | Ipamorelin | Tesamorelin |
|---|---|---|
| What it is | A five-residue peptide that does not correspond to any natural peptide sequence. | A 44-residue peptide: an analog of human growth hormone-releasing hormone with an N-terminal trans-3-hexenoyl group. |
| How they relate | Different molecules. Ipamorelin is a synthetic construct that does not correspond to any natural peptide sequence. Tesamorelin is a synthetic analog of the full 44-residue human growth hormone-releasing hormone. | |
| CAS number | 170851-70-4 | 218949-48-5 |
| Molecular formula | C38H49N9O5 | C221H366N72O67S |
| Molecular weight | 711.85 g/mol | 5,135.86 g/mol |
| Sequence | Aib-His-D-2Nal-D-Phe-Lys-NH2 | trans-3-hexenoyl-Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2 |
| Evidence base | Two human studies in the literature reviewed for it. One was a pharmacokinetic-pharmacodynamic study in healthy male volunteers.[1] The other, a randomized phase 2 trial, missed its key endpoint and its secondary analyses.[2] | Human studies, which supported an approval for one indication. A pooled analysis of two phase 3 trials covered 806 randomized participants.[3] Their primary endpoints were imaging surrogates. The trial papers were manufacturer-sponsored. |
| Regulatory status | The FDA has not approved Ipamorelin for human use. | The FDA approved tesamorelin acetate in 2010 for one therapeutic indication.[4][5] That approval is current. |
| Compared head-to-head? | No direct comparison found in PubMed (searched October 2026).[6] | |
| Handling difference | Neither contains a cysteine. Ipamorelin contains no sulfur and so no methionine; Tesamorelin contains one methionine, which oxidizes on air exposure. | |
How Ipamorelin and Tesamorelin differ
Ipamorelin and Tesamorelin are different molecules. Ipamorelin is a five-residue peptide, a synthetic construct that does not correspond to any natural peptide sequence. Tesamorelin is a synthetic analog of the full 44-residue human growth hormone-releasing hormone, with a trans-3-hexenoyl group on its N-terminus.
The literature reviewed for Ipamorelin includes two published human studies. One was an early-phase pharmacokinetic-pharmacodynamic study in healthy male volunteers.[1] The other was a randomized phase 2 trial of 114 participants, and it missed its key endpoint and its secondary analyses.[2] Almost everything else known about Ipamorelin comes from preclinical pharmacology. The foundational pharmacology study, published by Raun and colleagues in 1998, used rat cells in vitro, anesthetized rats and conscious swine.[7] Much of the defining preclinical work comes from the original developer, which raises the usual question of independent replication.
Human studies of Tesamorelin supported an approval for one indication. A pooled analysis of its two phase 3 trials covered 806 randomized participants.[3] In the literature reviewed for Tesamorelin, those trials used imaging surrogates as primary endpoints, not clinical outcomes. The two trial papers and the pooled analysis were manufacturer-sponsored, with sponsor-affiliated co-authors. A randomized phase 2 trial of 73 participants, in another indication, found no significant difference.[8]
The FDA has not approved Ipamorelin for human use. The FDA approved tesamorelin acetate in 2010 for one therapeutic indication.[4][5] That approval is current, and it belongs to tesamorelin acetate and to that one indication. Tesamorelin acetate is the active ingredient of a prescription medicine sold under another name. The material supplied here is a research-grade preparation, is not that medicine, and holds no marketing authorization.
Ipamorelin contains no sulfur, so it has no cysteine and no methionine. Tesamorelin's chemical liabilities are ordinary. It contains no cysteine but has a single methionine, which oxidizes to a sulfoxide on air exposure. Its nitrogen count indicates asparagine and glutamine, which both deamidate; Ipamorelin contains neither. Ipamorelin's remaining chemical liabilities are general: amide hydrolysis under strong acid or alkali, slow near neutral pH, and oxidation of aromatic side chains, far slower than for a tryptophan. For Tesamorelin, the principal stability concern is physical rather than chemical: a chain long enough to fold can aggregate on repeated freezing and thawing.
Have Ipamorelin and Tesamorelin been compared directly?
No direct comparison of Ipamorelin with Tesamorelin was found in a PubMed search run in October 2026.[6] That search covers PubMed only.
Read more on each compound
Ipamorelin
Frequently Asked Questions
Is Ipamorelin the same as Tesamorelin?+−
Ipamorelin and Tesamorelin are different molecules. Ipamorelin is a synthetic five-residue peptide that does not correspond to any natural peptide sequence. Tesamorelin is a synthetic analog of the full 44-residue human growth hormone-releasing hormone, with a trans-3-hexenoyl group on its N-terminus.
Is Ipamorelin or Tesamorelin approved?+−
The FDA has not approved Ipamorelin for human use; it approved tesamorelin acetate in 2010 for one therapeutic indication. Tesamorelin acetate is the active ingredient of a prescription medicine sold under another name. The material supplied here is a research-grade preparation, is not that medicine, and holds no marketing authorization.
References
- 1Gobburu JV, Agerso H, Jusko WJ, Ynddal L. Pharm Res. 1999;16(9):1412-6. doi:10.1023/a:1018955126402. PMID 10496658.
- 2Beck DE, Sweeney WB, McCarter MD. 2014;29(12):1527-1534. doi:10.1007/s00384-014-2030-8. PMID 25331030.
- 3Falutz J, Mamputu JC, Potvin D, Moyle G, Soulban G, Loughrey H, et al. J Clin Endocrinol Metab. 2010;95(9):4291-4304. PMID 20554713.
- 4US Food and Drug Administration, Center for Drug Evaluation and Research. Approval letter for tesamorelin, 10 November 2010 (Reference ID 2863003).
- 5US Food and Drug Administration, Drugs@FDA. Approval record whose active ingredient is tesamorelin acetate; marketing status Prescription. Retrieved via api.fda.gov/drug/drugsfda.json on products.active_ingredients.name "TESAMORELIN ACETATE", 3 October 2026.
- 6PubMed search via NCBI E-utilities, run 3 October 2026; records entered to 2 October 2026. Query: ("ipamorelin"[tiab]) AND ("tesamorelin"[tiab]) AND ("1800/01/01"[edat] : "2026/10/02"[edat]). 6 records; none was a direct comparison of the two compounds.
- 7Raun K, Hansen BS, Johansen NL, Thogersen H, Madsen K, Ankersen M, et al. Eur J Endocrinol. 1998 Nov;139(5):552-61. doi:10.1530/eje.0.1390552. PMID 9849822.
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