Masteron is the historical trade name for drostanolone propionate, the 17β-propionate ester of drostanolone. The product name must not be used as though it identifies unesterified drostanolone: the ester changes formula mass and physicochemical behaviour.
What Are the Key Masteron Research Specifications?
| Specification | Research record |
|---|---|
| Compound | Masteron |
| Category | steroids |
| Listed purity | >99% |
| Molecular weight | 360.54 g/mol for drostanolone propionate |
| Intended use | Laboratory research only |
What is the correct structure and molecular weight?
Drostanolone is 2α-methyl-5α-dihydrotestosterone and has a molecular mass near 304.47 g/mol. Drostanolone propionate has formula C23H36O3 and molecular mass 360.54 g/mol. A value of 334.5 g/mol does not match either defined structure. Researchers should verify the actual form by formula, CAS record, LC-MS and NMR rather than infer it from the trade name.
The 5α-reduced steroid nucleus means the active moiety is not a substrate for aromatization. The 2α-methyl group distinguishes drostanolone from DHT; the 17β-propionate is a pro-moiety that must be hydrolysed to generate the free 17β-hydroxyl steroid.
How does drostanolone propionate work in research?
After ester hydrolysis, drostanolone can bind the androgen receptor and alter AR-dependent transcription. In a cell-free binding assay or a cell line with little esterase activity, the intact ester may not reproduce the pharmacology of the active moiety. This is why receptor activity and formulation-release questions should be studied separately.
Which experiments are appropriate?
For structure–activity work, compare drostanolone, drostanolone propionate, DHT and testosterone on a molar basis. Measure ester hydrolysis directly in the chosen matrix. Use AR-negative or AR-knockout controls and an AR antagonist to test pathway dependence. Reporter assays should be paired with endogenous AR target genes because promoter context can alter apparent potency.
How Should Masteron Be Handled and Verified?
Define free steroid versus ester, polymorphic form and solvent. Verify identity by LC-MS and NMR; use a reference standard to support quantitative HPLC. Lipophilic steroids may adsorb to plastics or precipitate after aqueous dilution, so inspect stocks, keep vehicle concentration matched across conditions and measure final soluble concentration when possible. Protect solutions from prolonged heat and light.
Which Sources Support Masteron Research?
- PubChem record for drostanolone propionate (Masteron), including formula and mass: CID 224004.
- Gao et al., molecular pharmacology of androgen receptor signalling, Chemical Reviews (2005), DOI: 10.1021/cr020456u.
How Can Masteron Results Be Interpreted Without Overclaiming?
Begin interpretation with a falsifiable question and a predeclared primary readout. For Masteron, receptor activation, metabolism and ester or formulation behaviour are separate causal layers. A change in transcription cannot establish release kinetics, and a depot-like effect cannot establish intrinsic androgen-receptor potency. Report negative and null findings, not only the largest response. Show individual observations, biological replicates and uncertainty intervals, and identify whether replication means a new well, a new culture, a new animal or a new day.
A citable Masteron result states the species, cell line or biochemical system; exact molecular form; concentration and exposure; comparator; assay method; and statistical unit. Confirm that vehicle, pH, osmolality or precipitation did not create the phenotype. Conclusions should stay at the level tested: in vitro activity is not evidence of organism-level efficacy, and an animal phenotype is not a human claim.
Is Masteron for Research Use Only?
Drostanolone propionate is supplied for laboratory research only. It is not for human or veterinary use.
What Are Common Questions About Masteron?
What is Masteron?
Masteron is the historical trade name for drostanolone propionate, the 17β-propionate ester of drostanolone. The product name must not be used as though it identifies unesterified drostanolone: the ester changes formula mass and physicochemical behaviour.
How should researchers verify Masteron?
Confirm the exact molecular form on the lot certificate and pair chromatographic purity with an orthogonal identity method such as mass spectrometry or NMR. Use the molecular weight, counterion and content stated for that verified form when calculating molarity.
Is Masteron intended for human use?
Masteron is listed for controlled laboratory research only. It is not intended for human or veterinary use.