Tesamorelin and sermorelin are both growth-hormone-releasing hormone analogues, and they are searched against each other more than any other pair in their class. The record separates them more sharply than the searches suggest: one has two current US labels, a randomised trial and a biologic's application number; the other has a discontinued approval, an uncontrolled paediatric study and a compounding market. This page compares them on what the labels, registries and trials state, and converts each figure into molecules and syringe units. It recommends neither.
The full per-compound pages are the tesamorelin dosage page and the sermorelin dosage page; Peptifact's comparison covers the same pair from its own angle. The compounds themselves are covered in Medibact's Tesamorelin guide and Sermorelin guide.
Side by side
| Tesamorelin | Sermorelin | |
|---|---|---|
| Structure | GHRH 1-44 + hexenoyl group | GHRH 1-29, amidated |
| Amino acids | 44 | 29 |
| Molecular weight | 5,135.9 (free base, label) | 3,357.9 (PubChem) |
| US status | EGRIFTA SV and WR, current labels | GEREF, discontinued (NDA 020443, NDA 019863) |
| Application type | BLA 022505 (approved 2010-11-10) | NDA |
| Labelled or studied daily amount | 1.4 mg (SV), 1.28 mg (WR); 2 mg in the pivotal trial | 30 mcg/kg at bedtime in children (GEREF study) |
| Half-life on record | 8 min (SV) and 11 min (WR), subcutaneous | 4.3 min, intravenous infusion |
| Pivotal evidence | Randomised, placebo-controlled, 412 people with HIV | Open-label, uncontrolled, 110 children |
Sources and dates for every row are in the facts above and the list at the foot of the page.
Why one is a biologic and the other is not
Drugs@FDA lists tesamorelin's application as BLA 022505, with an original approval on 2010-11-10, and sermorelin's as NDAs. The difference is a counting rule, not a judgment about either molecule: 21 CFR 600.3(h)(6) defines a protein as an alpha amino acid polymer of more than 40 amino acids, and proteins are regulated as biological products. Tesamorelin, at 44, crosses the line; sermorelin, at 29, does not. Separately, and for a different reason, the two reach patients differently: tesamorelin through its labelled products, sermorelin through compounding since GEREF was discontinued.
Half-life: both are minutes
Pages comparing the two often describe tesamorelin as the longer-acting option. The current labels do not support that framing. EGRIFTA SV's label gives a mean elimination half-life of 8 minutes after a 1.4 mg subcutaneous dose in healthy subjects, and EGRIFTA WR's gives 11 minutes after 1.28 mg. For sermorelin, Soule, King and Millar infused GHRH(1-29)-NH2 intravenously in 10 men and measured a disappearance half-time of 4.3 ± 1.4 minutes (JCEM 1994, PMID 7962295). A subcutaneous half-life includes absorption and an intravenous one does not, so the numbers are not directly comparable; what they share is the order of magnitude. Neither is present for hours. The growth-hormone response each prompts lasts longer than the peptide itself: a 1993 intravenous study of GHRH(1-29)-NH2 in 30 men found growth hormone elevated for about 3 hours after a rapidly eliminated dose (PMID 8329825).
The same milligram is not the same number of molecules
Tesamorelin is the larger molecule, so a milligram of it holds fewer molecules. Per milligram, sermorelin supplies about 1.53 times as many (5,135.9 ÷ 3,357.9).
| 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 |
| Sermorelin, clinic figure (low) | 200 mcg | ≈0.06 |
| Sermorelin, clinic figure | 300 mcg | ≈0.09 |
| Sermorelin, clinic figure (high) | 500 mcg | ≈0.15 |
| Sermorelin, GEREF study scaled to 70 kg | 2.1 mg | ≈0.63 |
The clinic figures for sermorelin are those this site recorded from clinic, pharmacy and vendor pages on 2026-09-18; they are compounding conventions, not label figures. Two readings from the table: tesamorelin's labelled daily amount is about three times the molecules of a 300 mcg sermorelin figure, and the paediatric study's per-kilogram amount, scaled to an adult, would be larger than either, which shows the adult clinic figures were not derived from it. Molecules are not effect; the two analogues differ in receptor binding and breakdown, and no study compares them head to head.
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 |
| Sermorelin 200 mcg | 8 units | 4 units | 2 units |
| Sermorelin 300 mcg | 12 units | 6 units | 3 units |
| Sermorelin 500 mcg | 20 units | 10 units | 5 units |
Where the concentrations come from: 2.5 mg/mL is a 5 mg vial with 2 mL; 5 mg/mL is a 5 mg vial with 1 mL or a 10 mg vial with 2 mL; 10 mg/mL is a 10 mg vial with 1 mL. The labelled products set their own: EGRIFTA SV reconstitutes 2 mg in 0.5 mL (4 mg/mL, so 1.4 mg is 35 units) and EGRIFTA WR an 11.6 mg vial with 1.3 mL to a stated 8 mg/mL (so 1.28 mg is 16 units). Sermorelin's microgram figures sit at two to five units at 10 mg/mL, at the edge of a 1 mL barrel's 2-unit marks, which is the arithmetic reason its vials are usually worked more dilute. The tesamorelin calculator and sermorelin calculator do the same for any figure entered, and the mg to units page sets out the formula.
Together, and what is not established
No trial of tesamorelin with sermorelin was found. Both act at the GHRH receptor, which the stacking guide treats as a class collision: two compounds competing for one receptor rather than adding a mechanism. Not established by any source read for this page: a head-to-head comparison of the two, any sermorelin data in adults at the clinic figures, and any labelled use of tesamorelin outside HIV-associated lipodystrophy. Nothing here is a suggested amount; decisions about amounts belong with a prescriber.
Sources and dates
Opened 2026-09-23: the EGRIFTA SV (set id 3d783378-b02d-4f19-99dd-0fc91a042224) and EGRIFTA WR (set id 839334d3-8c1d-4c26-9036-2ab524a6ea75) labels via openFDA, both effective 2026-07-29, sections 2, 11 and 12.3; Drugs@FDA records for BLA 022505, NDA 020443 and NDA 019863 via openFDA; 21 CFR 600.3(h)(6) via the eCFR API; PubChem records for tesamorelin (CID 16137828) and sermorelin (CID 16132413); abstracts via NCBI E-utilities for Falutz et al., NEJM 2007 (PMID 18057338), Thorner et al., JCEM 1996 (PMID 8772599), Soule, King and Millar, JCEM 1994 (PMID 7962295) and Wilton et al., Acta Paediatr Suppl 1993 (PMID 8329825). The sermorelin clinic figures are from this site's sermorelin page (sources read 2026-09-18). Molar and unit arithmetic by this site. Corrections go to the contact page.