Catalogue / Sermorelin
Sermorelin
Also written as GHRH (1-29) amide, GRF (1-29).
The N-terminal 29 residue fragment of human growth hormone releasing hormone, C-terminally amidated, and the parent of the modified analogues sold alongside it.
| Molecular formula | C149H246N44O42S |
| Average mass | 3357.88 Da |
| Monoisotopic mass | 3355.8187 Da |
| Residues | 29 |
| Termini | C-terminal amide |
| Class | Growth hormone secretagogues |
| Determination | Peptide analysis, specialist compound |
| Price | 590 USD |
Computed at build time from the composition shown on this page, not transcribed from a supplier datasheet.
Sermorelin has an average molecular weight of 3357.88 daltons and a monoisotopic mass of 3355.8187 daltons. Identity is confirmed by matching the measured deconvoluted mass to that figure, and purity is reported separately by reversed-phase chromatography at 214 nm. The two numbers answer different questions and neither substitutes for the other.
| One letter | YADAIFTNSYRKVLGQLSARKLLQDIMSR |
| Three letter | Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg |
| Modifications | C-terminal amide |
The formula and both masses in the table above are derived from this sequence and these terminal modifications. A reader who believes a figure is wrong can check the composition rather than take the number on trust, which is the point of publishing it this way.
A sequence is not an identity result. It is the expected composition against which a measured mass is compared, and the comparison is what appears on the certificate.
| Charge | m/z |
|---|---|
| [M+3H]3+ | 1119.614 |
| [M+4H]4+ | 839.962 |
| [M+5H]5+ | 672.171 |
These are the ions an electrospray source is expected to produce for a neutral mass of 3355.8187 daltons, computed from the monoisotopic mass and the proton mass. They are what a raw spectrum should show before deconvolution.
A report that gives only a deconvoluted mass without the charge states it was derived from cannot be checked. Deconvolution is a calculation, and a calculation whose inputs are not shown is an assertion.
| Sermorelin and the modified GRF analogues are routinely conflated. The modified versions carry substitutions at positions 2, 8, 15 and 27, each of which changes the mass. |
| Position 2 alanine is the site of rapid dipeptidyl peptidase cleavage. The two-residue-shorter degradation product is a real impurity, not a synthesis error, and appears with age. |
| Methionine at position 27 oxidises, adding 16 daltons. |
Every compound fails in its own way. A generic peptide method applied without regard to these specifics produces a number that looks like a result and is not one.
Short synthetic peptides, most carrying D-amino acids or unnatural residues that make them resistant to serum peptidases and invisible to sequence-only reasoning.
LC-MS identity against a certified reference standard, purity by RP-HPLC at 214 nm. D-isomers are not resolved by a conventional C18 column and are not claimed to be.
Where the delivered milligram figure matters rather than the percentage, net peptide content by combustion analysis and water by Karl Fischer are added, and the certificate carries a closed mass balance instead of a single purity number.
| LC-MS identity | Measured mass |
| RP-HPLC purity | Area at 214 nm |
| Net peptide content | Milligrams |
| Water content | Karl Fischer |
| Counter-ion | Ion chromatography |
| Bacterial endotoxins | USP <85> |
What is the molecular weight of Sermorelin?
The average molecular weight is 3357.88 daltons and the monoisotopic mass is 3355.8187 daltons, computed from the sequence YADAIFTNSYRKVLGQLSARKLLQDIMSR shown on this page. Both figures are calculated rather than transcribed, so they can be checked against the stated composition.
How is Sermorelin tested for purity and identity?
LC-MS identity against a certified reference standard, purity by RP-HPLC at 214 nm. D-isomers are not resolved by a conventional C18 column and are not claimed to be. Purity describes the chromatographable fraction only and is not the same quantity as the peptide mass delivered per vial.
What goes wrong when Sermorelin is analysed?
Sermorelin and the modified GRF analogues are routinely conflated. The modified versions carry substitutions at positions 2, 8, 15 and 27, each of which changes the mass.
What does Sermorelin analysis cost at ANALYTON?
Peptide analysis, specialist compound is priced at 590 US dollars, covering the determinations described on this page. Content, safety and elemental determinations are ordered alongside and are priced separately on the price list.
Other compounds in this class
Updated 2026-09-01. Masses computed at build, not transcribed.