Tesamorelin and ipamorelin are searched against each other more than either is searched against most of its own class. They are not alternatives in the way the searches imply: they work through different receptors, one has two current US labels and the other has none, and their figures are written in different units, milligrams for one and micrograms for the other. This page compares them on what the labels, registries and studies state (read 2026-10-06), puts both on a molecule scale and in syringe units, and recommends neither.
The per-compound pages are the tesamorelin dosage page and the ipamorelin dosage page. The two used together are covered on the tesamorelin and ipamorelin stack page; this page is the comparison. Peptifact's comparison of the pair covers it from its own angle. The compounds themselves are covered in Medibact's Tesamorelin guide and Ipamorelin guide.
Side by side
| Tesamorelin | Ipamorelin | |
|---|---|---|
| Class | GHRH analogue (GHRH 1-44 + hexenoyl group) | Ghrelin-receptor agonist (growth hormone secretagogue) |
| Receptor | GHRH receptor | GHS-R1a (ghrelin receptor) |
| Amino acids | 44 | 5 |
| Molecular weight | 5,136 | 711.9 |
| US label | EGRIFTA SV (1.4 mg daily), EGRIFTA WR (1.28 mg daily) | None |
| Labelled use | Excess abdominal fat in HIV-infected adults with lipodystrophy | None |
| Pivotal human evidence | Randomised, placebo-controlled, 412 people (2 mg daily, 26 weeks) | Two intravenous ileus trials; the larger had 114 patients and missed its endpoint |
| Half-life on record | 8 min (SV) and 11 min (WR), subcutaneous | 2 h terminal, intravenous |
| Registry records (2026-10-06) | 24 | 3, all intravenous |
| Figures in circulation | 1–2 mg daily | 100–300 mcg per injection |
Sources and dates for each row are in the facts above and the list at the foot of the page.
Two receptors, two signals
Growth hormone release from the pituitary is driven by two separate inputs: GHRH, acting at its own receptor, and ghrelin, acting at the growth hormone secretagogue receptor. Tesamorelin imitates the first; ipamorelin the second. That is why the comparison is not like-for-like, and why combination pages describe the pair as complementary. The paper that introduced ipamorelin called it "the first selective growth hormone secretagogue", reporting growth hormone release in animals without the cortisol or ACTH release earlier secretagogues caused (Raun et al., European Journal of Endocrinology 1998, PMID 9849822). Tesamorelin's selectivity question is a different one: its labels concern IGF-1 monitoring and glucose, not cortisol.
A milligram against a microgram
The figures look a thousandfold apart (1.4 mg against 200 mcg), but most of that gap is molecular size. Ipamorelin's molecule weighs about one seventh of tesamorelin's, so a microgram of it carries about 7.2 times as many molecules.
| Figure | Amount | Micromoles |
|---|---|---|
| Tesamorelin, EGRIFTA WR | 1.28 mg | ≈0.25 |
| Tesamorelin, EGRIFTA SV | 1.4 mg | ≈0.27 |
| Tesamorelin, pivotal trial | 2 mg | ≈0.39 |
| Ipamorelin, figure in circulation (low) | 100 mcg | ≈0.14 |
| Ipamorelin, figure in circulation | 200 mcg | ≈0.28 |
| Ipamorelin, figure in circulation (high) | 300 mcg | ≈0.42 |
| Ipamorelin, largest trial (0.03 mg/kg at 70 kg, IV) | 2.1 mg | ≈2.95 |
On a molecule count, then, the common ipamorelin figures sit in the same range as tesamorelin's labelled doses, not three orders of magnitude below them. Molecule counts are not potency: the two act at different receptors, so an equal number of molecules says nothing about an equal effect. The comparison only removes a false impression created by the units. The trial row shows the other gap: the one sizeable ipamorelin trial used about ten times the molecules of any figure in circulation, intravenously.
Half-lives measured differently
Tesamorelin's labels give a mean elimination half-life of 8 minutes (EGRIFTA SV, 1.4 mg) and 11 minutes (EGRIFTA WR, 1.28 mg) after subcutaneous injection in healthy subjects. Ipamorelin's only human pharmacokinetic study infused it intravenously over 15 minutes in eight healthy men per dose level and reported a terminal half-life of 2 hours and a single growth-hormone peak at 0.67 hours, about 40 minutes, falling to negligible levels at every dose (Gobburu et al., 1999). An intravenous half-life excludes absorption and a subcutaneous one includes it, so the two numbers are not directly comparable; no study measured both peptides the same way.
Each figure as syringe units
Units on a U-100 syringe = mg ÷ mg/mL × 100. Research-market vials of both are commonly labelled 5 mg and 10 mg.
| Amount | 2.5 mg/mL | 5 mg/mL | 10 mg/mL |
|---|---|---|---|
| Tesamorelin 1.28 mg | 51.2 units | 25.6 units | 12.8 units |
| Tesamorelin 1.4 mg | 56 units | 28 units | 14 units |
| Tesamorelin 2 mg | 80 units | 40 units | 20 units |
| Ipamorelin 100 mcg | 4 units | 2 units | 1 unit |
| Ipamorelin 200 mcg | 8 units | 4 units | 2 units |
| Ipamorelin 300 mcg | 12 units | 6 units | 3 units |
The labelled tesamorelin products set their own concentration: EGRIFTA SV is reconstituted to 4 mg/mL (1.4 mg = 35 units) and EGRIFTA WR to 8 mg/mL (1.28 mg = 16 units); the WR label specifies bacteriostatic water and the SV label sterile water, and states that the two are not substitutable. Ipamorelin's microgram figures fall to one to three units at 10 mg/mL, below the 2-unit marks of a 1 mL barrel, which is the arithmetic reason its vials are usually worked more dilute. The tesamorelin calculator and ipamorelin calculator do the same for any figure entered.
What is not established
Not established by any source read for this page: a head-to-head comparison of the two, any human trial of them together, any subcutaneous human dosing study of ipamorelin, and any labelled use of tesamorelin outside HIV-associated lipodystrophy. The pairing's comparisons with the other GHRH analogues are on tesamorelin vs sermorelin and tesamorelin vs CJC-1295. Nothing here is a suggested amount; decisions about amounts belong with a prescriber.
Sources and dates
Opened 2026-10-06: the EGRIFTA WR (set id 839334d3-8c1d-4c26-9036-2ab524a6ea75, revised 03/2025) and EGRIFTA SV (set id 3d783378-b02d-4f19-99dd-0fc91a042224) labels via the DailyMed web services, section 2 and section 5 (injection site reactions); PubChem records CID 16137828 and CID 9831659; ClinicalTrials.gov API v2 intervention searches for tesamorelin and ipamorelin; the Gobburu et al. 1999 abstract (PMID 10496658) via NCBI E-utilities. The label half-lives, the Falutz 2007 trial, the Raun 1998 and Beck 2014 ipamorelin papers and the figures in circulation are as recorded on this site's tesamorelin, ipamorelin and tesamorelin-vs-sermorelin pages (sources read 2026-09-18 and 2026-09-23). Molar and unit arithmetic by this site. Corrections go to the contact page.