Peptide reference · 44-residue GHRH analog with N-terminal hexenoyl group
Tesamorelin COA check: molecular weight, formula and what to look for
Use these reference values to check the identity result on a Tesamorelin Certificate of Analysis. The theoretical average molecular weight of Tesamorelin is 5,135.78 Da and the monoisotopic mass is 5,132.717 Da.
Check a Tesamorelin COA nowTesamorelin reference data
| Name | Tesamorelin |
|---|---|
| Also known as | TH9507 |
| Type | 44-residue GHRH analog with N-terminal hexenoyl group |
| Molecular formula | C221H366N72O67S |
| Average molecular weight | 5,135.78 g/mol (Da) |
| Monoisotopic mass | 5,132.7166 Da |
| Residues | 44 |
| Reference source | PubChem CID 16137828 (formula and mass cross-checked) |
Expected mass spectrometry ions
A Tesamorelin COA may list one of these m/z values instead of the neutral mass. That is still consistent with Tesamorelin. How charge states work.
| Ion | m/z (monoisotopic) | m/z (average) |
|---|---|---|
| [M+3H]3+ | 1,711.91 | 1,712.93 |
| [M+4H]4+ | 1,284.19 | 1,284.95 |
| [M+5H]5+ | 1,027.55 | 1,028.16 |
| [M+6H]6+ | 856.46 | 856.97 |
What else can show up on a Tesamorelin COA
Masses calculated from Tesamorelin's formula for the adducts, degradation products and synthesis impurities a lab report can show. A match tells you what the extra peak probably is.
| Signal | Value | What it means |
|---|---|---|
| Na adduct, deconvoluted (M + 21.98) | 5,154.70 Da | Sodium adduct: an MS artifact, not a separate impurity. The [M+Na]+ ion itself is at M + 22.99 |
| K adduct, deconvoluted (M + 37.96) | 5,170.67 Da | Potassium adduct: an MS artifact. The [M+K]+ ion itself is at M + 38.96 |
| TFA adduct (M + 113.99) | 5,246.71 Da | Trifluoroacetic acid from purification seen as an adduct; residual TFA salt is real vial content |
| M + 16 (oxidation) | 5,148.71 Da | Oxidation of Met |
Adduct rows are deconvoluted masses (the shift seen against [M+H]+); the singly charged [M+Na]+ ion itself sits at M + 22.99. Deletion masses alone can't say which copy of a repeated residue is missing.
At over 5 kDa, Tesamorelin is harder to purify; 98% or higher with one sharp main peak is a strong result. The full checklist is in how to read a peptide COA.
Tesamorelin-specific things to watch
Tesamorelin is the full 44-residue GHRH sequence with a trans-3-hexenoyl group on the N-terminus, about 5135.9 Da average.
At over 5 kDa, the average and monoisotopic masses differ by about 3 Da, so check which value the COA reports. ESI spectra typically show charge states such as 1028.2 m/z (5+) and 857.0 m/z (6+).
Like sermorelin, tesamorelin contains methionine, so a +16 Da peak can indicate oxidation.
Compounds with similar mass
If a COA's mass is off, compare it with these neighbors. A match to one of them can point to a mislabeled product.
- Thymosin Beta-4: 4,963.44 Da (-172.34 Da)
- Tirzepatide: 4,813.45 Da (-322.33 Da)
- Retatrutide: 4,731.35 Da (-404.43 Da)
Sources
- PubChem CID 16137828: Tesamorelin formula and reference mass.
- CIAAW: Standard atomic weights: Used to calculate average molecular weights.
- NIST CODATA: proton mass: Used to convert m/z charge states to neutral mass.
- PeptideCOACheck methodology: How the checker's thresholds work.
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Frequently asked questions
What is the molecular weight of Tesamorelin?
The average molecular weight of Tesamorelin (C221H366N72O67S) is 5,135.78 Da and its monoisotopic mass is 5,132.7166 Da, calculated from the molecular formula and cross-checked against PubChem CID 16137828.
What other masses can show up on a Tesamorelin COA?
Besides the main peak, a Tesamorelin COA can show a sodium adduct (deconvoluted mass near 5,154.70 Da) and an oxidation product near 5,148.71 Da. The table on this page lists every expected variant with its mass.
For laboratory research use only. This page describes analytical chemistry data. It is not medical advice and makes no claim about effects in humans or animals.