Tesamorelin vs Ipamorelin
Tesamorelin and ipamorelin both raise growth hormone release, but through different receptors. Tesamorelin is a 44-amino-acid GHRH analogue that acts on the pituitary GHRH receptor and has large randomised human trials, while ipamorelin is a five-amino-acid ghrelin receptor agonist studied mostly in rats.
Side by side
| Tesamorelin | Ipamorelin | |
|---|---|---|
| Class | Growth hormone-releasing hormone (GHRH) analogue; stabilised GHRH(1-44), 44 amino acids | Growth hormone secretagogue; ghrelin (GHS-R1a) receptor agonist, pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Mechanism | Acts on the pituitary GHRH receptor, raising basal and pulsatile growth hormone release and IGF-1; does not act on the ghrelin receptor | Acts on the ghrelin receptor; in rats and pigs it released growth hormone without raising ACTH or cortisol |
| What's studied | Abdominal fat in people with HIV, liver fat, muscle, blood glucose in type 2 diabetes, cognition | Growth hormone release, postoperative ileus, bone and muscle in rats |
| Strength of the evidence | Eight human studies, most of them randomised, placebo-controlled trials (up to n=410), nearly all in people with HIV | One small human phase 2 trial (no benefit over placebo on its efficacy endpoints) and one pharmacokinetic study in healthy men; the rest in rats and pigs |
| Forms sold here | Lyophilised powder vial | Lyophilised powder vial |
| Sizes sold here | 5 mg and 10 mg vials | 10 mg vial |
| Storage | −20 °C, dry and dark; 2–8 °C once mixed, use within 28 days | −20 °C, dry and dark; 2–8 °C once mixed, use within 28 days |
| Cited studies on our pages | 8 | 8 |
Key differences
Receptor: tesamorelin copies the natural GHRH signal at the GHRH receptor, while ipamorelin acts on the separate ghrelin receptor. The two are different routes to growth hormone release, which is why they are often discussed together.
Size: tesamorelin is a 44-amino-acid chain based on the full human hormone, and ipamorelin is a five-residue peptide containing non-natural amino acids.
Evidence: tesamorelin has large phase 3 trials and is FDA-approved in the United States for excess abdominal fat in people with HIV. Ipamorelin's human data are limited to one post-surgical phase 2 trial and one single-infusion study.
FAQ
What is the difference between tesamorelin and ipamorelin?
Tesamorelin is a GHRH analogue that acts on the pituitary GHRH receptor. Ipamorelin is a growth hormone secretagogue that acts on the ghrelin receptor. Both raise growth hormone release, but through different receptors and with very different amounts of human evidence.
Which is better studied, tesamorelin or ipamorelin?
Tesamorelin, by a wide margin. Its cited studies are human trials, including two randomised placebo-controlled trials of about 400 people each. Ipamorelin's controlled human data are one phase 2 trial of 114 post-surgical patients that found no significant benefit over placebo.
Does ipamorelin raise cortisol?
In the 1998 rat and pig studies, ipamorelin did not raise ACTH or cortisol, even at doses more than 200 times the dose needed for half its growth hormone effect. That selectivity is what separated it from GHRP-6 and GHRP-2 in those studies.
Are tesamorelin and ipamorelin legal in Australia?
Neither is registered on the ARTG, and there is no TGA-approved product containing either one. Tasman supplies both as research chemicals for laboratory research only, not for human consumption.