These three peptides are sold side by side on the same clinic menus, usually described in the same sentence, and they are not equivalent in any respect that matters. Two of them act on the same receptor; the third acts on a different one. One has been through phase 3 trials and carries an FDA approval; the other two have not. Here is the comparison laid out on the axes that actually separate them.
They do not act on the same receptor
Sermorelin and tesamorelin are both analogs of growth-hormone-releasing hormone: they bind the GHRH receptor on the pituitary and amplify the body’s own pulsatile GH release. Sermorelin is the truncated GHRH(1-29) fragment; tesamorelin is a stabilized GHRH analog developed for a specific clinical indication.
Ipamorelin is not in that family. It is a ghrelin-receptor (GH secretagogue receptor) agonist, and its claim to attention when first characterized was selectivity: it was described as the first selective growth hormone secretagogue, releasing GH with a potency comparable to earlier peptides in its class but without the accompanying rise in adrenocorticotropic hormone and cortisol.[1] That is a real pharmacological distinction, and it is the reason ipamorelin displaced messier predecessors on clinic menus — the broader class comparison sits in growth hormone secretagogues.
| Sermorelin | Ipamorelin | Tesamorelin | |
|---|---|---|---|
| Class | GHRH analog (1-29) | Ghrelin-receptor agonist | Stabilized GHRH analog |
| Receptor | GHRH receptor | GH secretagogue receptor | GHRH receptor |
| Strongest evidence | Pediatric GH deficiency | Phase 2 in postoperative ileus | Two phase 3 trials in HIV lipodystrophy |
| FDA-approved product | No current US product | No | Yes — for HIV-associated excess abdominal fat |
| Evidence in healthy older adults | None | None | None |
Tesamorelin is the only one with phase 3 data
Tesamorelin was developed for a specific, well-defined problem: the excess visceral abdominal fat that accumulates in people with HIV on antiretroviral therapy. In the pivotal randomized trial, it reduced visceral adipose tissue against placebo in that population.[2] A pooled analysis of two multicenter, double-blind, placebo-controlled phase 3 trials with safety-extension data confirmed the effect and characterized the safety profile.[3]
That evidence earned an approval, and the approval is the narrowest part of the story: it is for reduction of excess abdominal fat in HIV-infected patients with lipodystrophy. It is not an approval for body composition in healthy adults, for athletic performance or for aging. We cover the trial detail in the tesamorelin evidence review and the two head-to-head questions in tesamorelin versus sermorelin and tesamorelin versus ipamorelin.
What sermorelin’s record actually consists of
Sermorelin has the longest clinical history of the three and the most misread one. Its documented use is in children with idiopathic growth hormone deficiency, where it served both as a diagnostic agent and as treatment.[4] That is a genuine evidence base for a genuine condition, and it is not the condition it is now sold for.
The adult data are thinner and more recent. An observational study in hypogonadal men reported that growth hormone secretagogue treatment raised serum IGF-1 levels.[5] Raising IGF-1 is a pharmacodynamic result — evidence the drug is doing something — not a clinical outcome, and the distinction is the entire argument. A broader review of growth hormone in the aging male sets out why the leap from “raises GH/IGF-1” to “improves how older adults function” has repeatedly failed to survive testing.[6] More on the individual compound in the sermorelin evidence review and ipamorelin versus sermorelin.
Choosing between them, honestly
If the question is which has the best evidence, the answer is tesamorelin, and it is not close — but its evidence is in a population most buyers are not in. If the question is which has the cleanest hormonal selectivity, ipamorelin has a defensible claim. If the question is which has the longest clinical track record, sermorelin does, in pediatric endocrinology.
If the question is which will change body composition in a healthy adult over 40, none of the three has evidence that answers it. That is not a hedge; it is the state of the literature, and the same conclusion reached from the muscle side in what actually treats age-related muscle loss. Practical handling questions — reconstitution, storage, injection technique — are covered in how to reconstitute peptides and how to store peptides, and the sourcing question in how to read a certificate of analysis. Providers prescribing these compounds are listed on our peptide provider comparison.
The honest bottom line
Two GHRH analogs and a ghrelin agonist, sold as if they were interchangeable. Tesamorelin has phase 3 evidence and an approval confined to HIV-associated lipodystrophy. Ipamorelin has a real selectivity advantage and no outcome trials. Sermorelin has decades of pediatric use and little adult evidence beyond IGF-1 movement. Anyone choosing between them for anti-aging purposes is choosing between three compounds that have never been tested for it.
