All products are for laboratory research purposes only. Not for human consumption.
Comparison
Tesamorelin vs Sermorelin: How They Differ
Both act at the same receptor, and both are analogues of the same hormone. The difference is how much of that hormone each one reproduces, and what has been attached to stop it being broken down. This page sets out what separates them and what the published literature does and does not compare.
The short answer
Side by side
| Tesamorelin | Sermorelin | |
|---|---|---|
| Classification | Synthetic GHRH(1-44) analogue, trans-3-hexenoyl modified | Synthetic GHRH(1-29) N-terminal fragment analogue |
| CAS number | 218949-48-5 | 86168-78-7 |
| Molecular formula | C221H366N72O67S | — |
| Molecular weight | 5135.9 g/mol | ~3358 g/mol |
| Sequence | 44-residue GHRH analogue with an N-terminal trans-3-hexenoyl group | 29-residue N-terminal fragment of GHRH (YADAIFTNSYRKVLGQLSARKLLQDIMSR) |
| Strengths | 10 mg, 20 mg | 5 mg, 10 mg |
| From, per vial | $15.57 £12.30 | $7.50 £5.93 |
| From, per box of 10 | $155.71 £123.01 | $75.00 £59.25 |
| Research status | An approved prescription medicine in the US and Canada for one specific indication. Not approved in the UK. Prohibited in competitive sport under the WADA S2 category. | Formerly approved as a licensed medicine in the United States under the name Geref; discontinued commercially in 2008. Not licensed in the UK. Prohibited in competitive sport under the WADA S2 category covering growth hormone releasing factors. |
In detail
What the research actually compares
Descriptions of published research activity and findings. Nothing here is a claim about what these products do, or a statement that either is safe or effective for any purpose.
Fragment against full length
Sermorelin is GHRH(1-29): the shortest N-terminal portion of the hormone that still activates the receptor fully. Removing more residues loses that activity, which is why 29 is where the fragment stops. Tesamorelin reproduces all 44 residues. In receptor terms the extra length adds little on its own, and the literature treats the two as equivalent agonists at the point of binding.
The modification is the real difference
Unmodified sermorelin is a substrate for dipeptidyl peptidase-4 and is cleared in minutes. The trans-3-hexenoyl group on tesamorelin's N-terminus obstructs that cleavage site, and that single change is responsible for most of the practical difference between the two compounds. A short-acting and a long-acting agonist at the same receptor is a useful pairing in research precisely because it isolates exposure time as a variable.
Regulatory histories that ran in opposite directions
Tesamorelin holds approval in the United States and Canada for one specific indication concerning excess visceral abdominal fat, supported by phase 3 trial data. Sermorelin held approval earlier, marketed as Geref, and was withdrawn commercially in 2008 — not on safety grounds but as a commercial decision. Neither is licensed in the UK, and neither is supplied here as anything other than research material.
Cost, for the same nominal quantity
At matched 10 mg strength the difference is substantial: sermorelin is $100.00 per box of ten vials against $155.71 for tesamorelin. Sermorelin is also available at 5 mg, which tesamorelin is not. If a protocol calls for a short-acting GHRH agonist specifically, the cheaper compound is also the correct one, which is not usually how this works.
References
- 1Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. J Clin Endocrinol Metab (2010). PMID 20554713
- 2Reduction in visceral adiposity is associated with an improved metabolic profile in HIV-infected patients receiving tesamorelin. Clin Infect Dis (2012). PMID 22495074
- 3Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor. Biochem Biophys Res Commun (1984). PMID 6435620
- 4Kinetics of dipeptidyl peptidase IV proteolysis of growth hormone-releasing factor and analogs. Biochim Biophys Acta (1992). PMID 1353684
- 5A comparison of the biological activities of authentic rat GRF(1-43)OH with the analogue rat GRF(1-29)NH2. Can J Physiol Pharmacol (1991). PMID 1829020
Links open the record on PubMed or PubMed Central. These are citations to published research on the individual compounds, not claims about either product or about the comparison itself.
Common questions
Which is better, tesamorelin or sermorelin?
Neither, and the question does not have a general answer because they are not interchangeable. They differ in how long they persist, not in what they do at the receptor. A study examining acute receptor response wants the short-acting one; a study concerned with sustained exposure wants the long-acting one. Choosing on price alone would be choosing on the wrong axis.
Is sermorelin the same as CJC-1295?
No, though they start from the same place. Both are built on the GHRH(1-29) fragment, but CJC-1295 carries four amino acid substitutions that resist enzymatic breakdown, and the DAC form adds an albumin-binding group on top of that. Sermorelin is the unmodified fragment with none of it.
Do they have the same side effect profile?
That is a clinical question about human use and we cannot answer it. Neither compound is supplied here for human use, no page on this site gives dosing or administration guidance, and the clinical literature for each concerns licensed products that this research-grade material is not.
