Purity ≥99% (HPLC). Selective antagonist of neurosteroid potentiation and direct gating of GABAA receptors. Selectively reduces the effects of 5α-reduced steroids compared to 5β-reduced steroids and displays no effect on potentiation evoked by barbiturates and benzodiazepines. Attenuates 3α,5α-THP-induced loss of righting reflex and total sleep time following i.c.v administration in rats. Synonym: 17-Phenyl-(3α,5α)-androst-16-en-3-ol