RAD-140 (Vosilasarm / Testolone) Research Standard

RAD-140, also indexed as vosilasarm and testolone (CAS 1182367-47-0), is a non-steroidal selective androgen receptor modulator (SARM) built on a benzonitrile / 1,3,4-oxadiazole scaffold rather than a steroid nucleus. It is supplied as a reference standard for laboratory work on androgen receptor (AR) pharmacology, tissue-selective nuclear receptor signalling, and analytical method development. Its value as a research tool is that it activates AR in a cell-context-dependent way, which makes it a workable probe for the question the SARM class exists to ask: how one receptor produces different transcriptional outputs in different tissues.^[1,2]

Mechanism of Action & Research Context

The molecular target is the androgen receptor (AR, NR3C4), a ligand-activated nuclear hormone receptor that functions as a transcription factor.

• Receptor binding and specificity. RAD-140 binds AR with high affinity, assayed against a panel of four nuclear receptors, and its downstream transcriptional output differs by cell type — activating AR in one carcinoma cell background while failing to do so in another. That divergence in a controlled in vitro comparison is the direct experimental basis for the word “selective” in the compound class name.^[2]

• Distinct genomic and non-genomic routes. Non-steroidal SARMs and the endogenous ligand DHT engage AR through different signalling arms and assemble different AR/cofactor complexes at androgen-responsive enhancers. The two ligand types are therefore not interchangeable in mechanistic experiments, which is the point of running both.^[4]

• Coregulator recruitment and dimerisation. In the wider class literature, a SARM can drive AR transcriptional activity while producing markedly less AR homodimerisation than DHT and recruiting only a restricted subset of cofactors — with p160 coactivators SRC1, TIF2 and NCoA3 notably absent in yeast two-hybrid interaction assays. Differential coregulator recruitment is the leading mechanistic account of tissue selectivity.^[5]

• MAPK/ERK signalling. In cultured rat hippocampal neurons, RAD-140 acts through AR with signalling dependent on the MAPK/ERK pathway: ERK phosphorylation increases, and the effect is blocked by the MEK inhibitor U0126. This gives a defined non-genomic readout in a non-reproductive tissue model.^[3]

Research Applications

Primary fields of in vitro and preclinical laboratory investigation include:

• AR binding and transactivation assays. Competitive ligand-binding measurements with nuclear-receptor counter-screens, paired with AR-driven reporter assays in transfected cell lines.^[1,2]

• Coregulator and dimerisation profiling. Yeast two-hybrid and peptide-interaction panels mapping which coactivators a given ligand does and does not recruit.^[4,5]

• Signalling pathway dissection. Phospho-ERK readouts with MEK inhibition to separate genomic from non-genomic AR signalling.^[3]

• Preclinical tissue-response models. Skeletal-muscle fibre cross-sectional area and tibial microarchitecture by micro-CT, the standard rodent readouts for characterising this compound class.^[6]

• Analytical and forensic method development. Reference material for chromatographic and mass-spectrometric identification, retention-time matching and metabolite characterisation, including liver-microsome incubations for phase I profiling.

Analytical Documentation

Purity and identity vary by manufacturing lot. Kimera Chems does not publish a single fixed purity figure for this item; refer to the batch-specific Certificate of Analysis (COA) issued for the lot received, which reflects third-party analytical testing for that lot.

Storage & Handling

Store at controlled room temperature. Keep tightly closed. Liquid formats: do not refrigerate or freeze. Cold storage may cause the solution to cloud or precipitate. If this occurs, return to room temperature and mix until clear.

Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.