Published · 4 references
HGH Fragment 176-191 vs Tesamorelin
HGH Fragment 176-191 and Tesamorelin are different molecules: HGH Fragment 176-191 is a 16-residue fragment of human growth hormone, and Tesamorelin is a 44-residue analog of human growth hormone-releasing hormone.
Structure at a glance
HGH Fragment 176-191 · 16 residues
Tesamorelin · 44 residues
Hex: N-terminal trans-3-hexenoyl group. NH2: C-terminal amide. Letters are one-letter amino acid codes.
Drawn from the product database. Each measure's bars share one scale.
| Property | HGH Fragment 176-191 | Tesamorelin |
|---|---|---|
| What it is | A 16-residue peptide: residues 176 to 191 at the C-terminal end of human growth hormone. | A 44-residue peptide: an analog of human growth hormone-releasing hormone with an N-terminal trans-3-hexenoyl group. |
| How they relate | Different molecules from different parents. HGH Fragment 176-191 corresponds to residues 176 to 191 of human growth hormone. Tesamorelin is an analog of the full 44-residue human growth hormone-releasing hormone. | |
| CAS number | 66004-57-7 | 218949-48-5 |
| Molecular formula | C78H123N23O22S2 | C221H366N72O67S |
| Molecular weight | 1,799.10 g/mol | 5,135.86 g/mol |
| Sequence | FLRIVQCRSVEGSCGF | trans-3-hexenoyl-YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL-NH2 |
| Evidence base | No published study has tested HGH Fragment 176-191 in people. In the literature reviewed for it, every laboratory and animal study described used AOD-9604 or a separate peptide, growth hormone residues 177 to 191. | Human studies, which supported an approval for one indication. A pooled analysis of two phase 3 trials covered 806 randomized participants.[1] Their primary endpoints were imaging surrogates. The trial papers were manufacturer-sponsored. |
| Regulatory status | No marketing authorization, and no FDA approval for human use. | The FDA approved tesamorelin acetate in 2010 for one therapeutic indication.[2][3] That approval is current. |
| Compared head-to-head? | No direct comparison found in PubMed (searched October 2026).[4] | |
| Handling difference | HGH Fragment 176-191 carries two sulfur atoms, enough for an intramolecular disulfide; sulfur chemistry is its principal liability. Tesamorelin's single sulfur is a methionine, which oxidizes on air exposure, and it contains no cysteine. | |
How HGH Fragment 176-191 and Tesamorelin differ
HGH Fragment 176-191 and Tesamorelin are different molecules from different parents. HGH Fragment 176-191 is the C-terminal 16-residue fragment of human growth hormone, corresponding to residues 176 to 191 of that hormone. Tesamorelin is an analog of the full 44-residue human growth hormone-releasing hormone, with a trans-3-hexenoyl group on its N-terminus.
No published study has tested HGH Fragment 176-191 in people. In the literature reviewed for HGH Fragment 176-191, every laboratory and animal study described used AOD-9604 or a separate peptide, growth hormone residues 177 to 191. Findings produced with either of those are not findings about HGH Fragment 176-191. A pooled analysis of Tesamorelin's two phase 3 trials covered 806 randomized participants.[1] In the literature reviewed for Tesamorelin, those trials used imaging surrogates as primary endpoints, not clinical outcomes. The two trial papers and the pooled analysis were manufacturer-sponsored, with sponsor-affiliated co-authors.
HGH Fragment 176-191 has no marketing authorization and no FDA approval for human use. The FDA approved tesamorelin acetate in 2010 for one therapeutic indication.[2][3] That approval is current, and it belongs to tesamorelin acetate and that one indication. It is not evidence about HGH Fragment 176-191. Tesamorelin acetate is the active ingredient of a prescription medicine sold under another name. The material supplied here is a research-grade preparation, is not that medicine, and holds no marketing authorization.
HGH Fragment 176-191 carries two sulfur atoms, exactly the number an intramolecular disulfide requires. Sulfur chemistry is its principal liability. Tesamorelin's single sulfur is a methionine, which oxidizes to a sulfoxide on air exposure. Tesamorelin contains no cysteine, so no disulfide is possible. For Tesamorelin, the principal stability concern is physical rather than chemical: a chain long enough to fold can aggregate on repeated freezing and thawing.
Have HGH Fragment 176-191 and Tesamorelin been compared directly?
No direct comparison of HGH Fragment 176-191 with Tesamorelin was found in a PubMed search run in October 2026.[4] That search covers PubMed only.
Read more on each compound
HGH Fragment 176-191
Frequently Asked Questions
Is HGH Fragment 176-191 the same as Tesamorelin?+−
HGH Fragment 176-191 and Tesamorelin are different molecules from different parents. HGH Fragment 176-191 is the C-terminal 16-residue fragment of human growth hormone. Tesamorelin is an analog of the full 44-residue human growth hormone-releasing hormone, with a trans-3-hexenoyl group on its N-terminus.
Is HGH Fragment 176-191 or Tesamorelin approved?+−
HGH Fragment 176-191 has no marketing authorization; the FDA approved tesamorelin acetate in 2010 for one therapeutic indication. That approval is not evidence about HGH Fragment 176-191. Tesamorelin acetate is the active ingredient of a prescription medicine sold under another name. The material supplied here is a research-grade preparation, is not that medicine, and holds no marketing authorization.
References
- 1Falutz J, Mamputu JC, Potvin D, Moyle G, Soulban G, Loughrey H, et al. 2010;95(9):4291-4304. PMID 20554713.
- 2US Food and Drug Administration, Center for Drug Evaluation and Research. Approval letter for tesamorelin, 10 November 2010 (Reference ID 2863003).
- 3US Food and Drug Administration, Drugs@FDA. Approval record whose active ingredient is tesamorelin acetate; marketing status Prescription. Retrieved via api.fda.gov/drug/drugsfda.json on products.active_ingredients.name "TESAMORELIN ACETATE", 3 October 2026.
- 4PubMed search via NCBI E-utilities, run 3 October 2026; records entered to 2 October 2026. Query: ("176-191"[tiab] OR "fragment 176-191"[tiab] OR "frag 176-191"[tiab] OR "hGH fragment"[tiab] OR "hGH 176-191"[tiab] OR "somatotropin (176-191)"[tiab]) AND ("tesamorelin"[tiab] OR "hexenoyl"[tiab] OR "trans-3-hexenoyl"[tiab]) AND ("1800/01/01"[edat] : "2026/10/02"[edat]). 1 record; none was a direct comparison of the two compounds.
Related comparisons
AOD-9604 vs HGH Fragment 176-191
AOD-9604 and HGH Fragment 176-191 are 16-residue peptides from the C-terminal end of human growth hormone that differ at one position.
Read ComparisonAOD-9604 vs Tesamorelin
AOD-9604 is a modified 16-residue peptide from the C-terminal end of human growth hormone; Tesamorelin is a 44-residue analog of human GHRH.
Read ComparisonCJC-1295 (No DAC) vs Tesamorelin
CJC-1295 (No DAC) carries four substitutions in human GHRH's first 29 residues; Tesamorelin is an analog of the full 44-residue hormone.
Read Comparison