Catalogue / Andarine
Andarine
Also written as S-4, GTx-007.
An aryl propanamide carrying a nitro group and an acetamido group, which makes it both the most strongly absorbing and the least stable compound in the class.
| Molecular formula | C19H18F3N3O6 |
| Average mass | 441.36 Da |
| Monoisotopic mass | 441.1148 Da |
| Molecular target | Androgen receptor |
| Electrospray polarity | Negative |
| Class | Androgen receptor modulators |
| Determination | Small molecule analysis, catalogue compound |
| Price | 267 USD |
Computed at build time from the composition shown on this page, not transcribed from a supplier datasheet.
Andarine has an average molecular weight of 441.36 daltons and a monoisotopic mass of 441.1148 daltons, computed from the molecular formula C19H18F3N3O6. Identity is confirmed by matching the measured mass against a certified reference standard, and purity is reported separately by reversed-phase chromatography at the compound's own ultraviolet maximum rather than at the 214 nm used for peptides. Neither figure states which enantiomer is present, which is a third determination on a chiral stationary phase.
| Ion | m/z |
|---|---|
| [M+H]+ | 442.122 |
| [M-H]- | 440.1075 |
Usable response for this compound is in negative mode. The other ion is given because it is the one a wrongly configured method looks for.
A molecule of this size does not produce the multiply charged envelope a peptide does. It produces one singly charged ion, and which polarity that ion appears in is decided by the functional groups rather than by convenience. A nitro or cyano aromatic responds in negative mode; a basic amine responds in positive.
That is why a screen acquired in a single polarity misses part of its own compound list, and why a non-detect from such a screen is not evidence that a substance is absent. The polarity used belongs on the certificate alongside the result.
| The nitro group reduces to the corresponding amine, losing 30 daltons. The reduction happens in light, in aged material, and in an ion source run too hot, so a peak 30 daltons light is a degradation product, an artefact of the source, or both, and the report has to say which was excluded. |
| Samples are handled under light protection from receipt. A determination run on material left on an open bench answers a question about the bench. |
| Strong ultraviolet absorbance makes it easy to see and easy to over-quantify: an area percentage at a wavelength where the target absorbs strongly and its impurities do not will read high. |
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.
Non-steroidal small molecules, most of them a single enantiomer of an aryl propanamide. They are not peptides and almost nothing carried over from peptide work applies: there is no amide backbone to detect at 214 nm, the molecules are a fraction of the mass of the smallest peptide in this catalogue, and the impurity that matters most is a mirror image that no achiral column separates from the target.
LC-MS identity against a certified reference standard, acquired in the ionisation polarity the compound actually responds in rather than in whichever polarity the instrument was left in. Purity by HPLC-UV at the compound's own absorbance maximum, not at 214 nm. Enantiomeric purity is a separate determination on a chiral stationary phase and is reported as a separate figure, because an achiral method cannot see it.
Where the delivered milligram figure matters rather than the percentage, assay against a certified reference standard gives content directly, and where no such standard exists quantitative NMR against a certified internal standard gives an absolute purity that needs no standard of the analyte at all.
| LC-MS identity | Measured mass |
| HPLC-UV purity | Area at the UV maximum |
| Enantiomeric purity | Chiral stationary phase |
| Water content | Karl Fischer |
| Elemental impurities | ICP-MS |
| Residual solvents | GC-MS |
What is the molecular weight of Andarine?
The average molecular weight is 441.36 daltons and the monoisotopic mass is 441.1148 daltons, computed from the molecular formula C19H18F3N3O6 shown on this page. Both figures are calculated rather than transcribed, so they can be checked against the stated composition.
How is Andarine tested for purity and identity?
LC-MS identity against a certified reference standard, acquired in the ionisation polarity the compound actually responds in rather than in whichever polarity the instrument was left in. Purity by HPLC-UV at the compound's own absorbance maximum, not at 214 nm. Enantiomeric purity is a separate determination on a chiral stationary phase and is reported as a separate figure, because an achiral method cannot see it. Purity is an area ratio measured at the compound's own ultraviolet maximum, and it describes the chromatographable fraction only. It says nothing about which enantiomer is present, because mirror images are not separated by an achiral column.
What goes wrong when Andarine is analysed?
The nitro group reduces to the corresponding amine, losing 30 daltons. The reduction happens in light, in aged material, and in an ion source run too hot, so a peak 30 daltons light is a degradation product, an artefact of the source, or both, and the report has to say which was excluded.
What does Andarine analysis cost at ANALYTON?
Small molecule analysis, catalogue compound is priced at 267 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.
Updated 2026-09-01. Masses computed at build, not transcribed.