LGD-4033 (Ligandrol) Research Standard

LGD-4033, also indexed as ligandrol and VK5211 (CAS 1165910-22-4), is a nonsteroidal selective androgen receptor modulator of the pyrrolidinyl-benzonitrile structural class, supplied as a reference standard for androgen receptor pharmacology and analytical method development.^[3]

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.

• Its own chemical class. The pyrrolidinyl-benzonitrile scaffold is catalogued separately from the arylpropionamides, quinolinones, indoles and phenyl-oxadiazoles in validated screening methods, so a panel intended to cover the class needs this standard specifically.^[3]

• The highest hair concentrations of the three common SARMs. Segmental hair analysis quantified ligandrol at 14–42 pg/mg against ostarine at 3–21 and andarine at 0.1–0.7 pg/mg. Hair testing detects both parent and numerous metabolites, and segmental analysis distinguishes long-term from single exposure.^[1]

• Covered by validated multi-matrix methods. Detection capability of 5 ng/mL in blood, and 0.1–1.0 ng/mL in urine screening.^[2,3]

• Distinct genomic and non-genomic routes. Nonsteroidal SARMs and endogenous androgens engage AR through different signalling arms and assemble different AR/cofactor complexes at androgen-responsive enhancers, so the two ligand types are not interchangeable in mechanistic work.^[4]

• Coregulator recruitment and dimerisation. 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 assays. Differential coregulator recruitment is the leading mechanistic account of tissue selectivity.^[5]

Research Applications

Primary fields of in vitro and preclinical laboratory investigation include:

• AR binding and transactivation assays with nuclear-receptor counter-screens.^[4,5]

• Trace-level and segmental analysis in hair, urine and blood.^[1,2,3]

• Cross-class method validation as the pyrrolidinyl-benzonitrile representative.^[3]

• Coregulator recruitment profiling against steroidal androgens.^[4,5]

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.