Tesamorelin vs Ipamorelin: two routes to GH release
Tesamorelin vs ipamorelin is a common comparison in growth hormone research: both stimulate GH release, but through different receptors. Tesamorelin is a 44-amino-acid GHRH analog acting on the GHRH receptor; ipamorelin is a 5-amino-acid peptide acting on the ghrelin receptor (GHS-R1a). Tesamorelin is the active ingredient of an FDA-approved medicine; ipamorelin is not approved. Both are supplied here, separately and as a blend, for laboratory research use only.
Side-by-side comparison
| Tesamorelin | Ipamorelin | |
|---|---|---|
| Class | GHRH analog | Ghrelin-receptor agonist (GHRP) |
| Receptor | GHRH receptor | GHS-R1a |
| Length | 44 amino acids | 5 amino acids |
| Key research | Randomised trials in HIV-associated abdominal fat | Animal studies of selective GH release |
| Regulatory status | Active ingredient of an FDA-approved medicine | Not approved |
Mechanism
GH release is controlled by two stimulating signals: GHRH and ghrelin. Tesamorelin mimics GHRH. Ipamorelin mimics ghrelin at the GHS-R1a receptor. Because the two receptors are separate, researchers often study GHRH analogs and ghrelin mimetics together.
What the studies found
Tesamorelin reduced visceral adipose tissue versus placebo in a 26-week randomised trial (Falutz et al., 2007). Ipamorelin was described as the first selective GH secretagogue: in animal studies it released GH without the large rises in ACTH and cortisol seen with some earlier GHRPs (Raun et al., 1998).
Frequently asked questions
What is the main difference between tesamorelin and ipamorelin?
Tesamorelin acts on the GHRH receptor; ipamorelin acts on the ghrelin receptor GHS-R1a. They are structurally unrelated.
Why are they sold as a blend?
Because they act on separate receptors, GHRH analogs and ghrelin mimetics are often studied together. The blend is supplied for research only.
Is tesamorelin or ipamorelin more studied in humans?
Tesamorelin has randomised human trials in HIV-associated abdominal fat; ipamorelin's published data are mostly early-phase and animal studies. See our research peptides guide (/learn/research-peptides) for how to compare suppliers and read test documents.
Can I buy tesamorelin and ipamorelin separately?
Yes. Both are sold individually and as a blend, for laboratory research only. See our research peptides guide (/learn/research-peptides) for how to compare suppliers and read test documents.
Is this product for human use?
No. PeptidesDirect sells this compound for laboratory research only. It is not a drug, food or cosmetic and is not for human or veterinary use. This page summarises published research and is not dosing or medical guidance.
References
- Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007. PubMed 18057338
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998. PubMed 9849822
Research compounds
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Research Use Only. Not for human or veterinary use. Not dosing or medical guidance.
