MW: 318.49, Purity ≥98% by HPLC. Allopregnanolone is an endogenous inhibitory pregnane neurosteroid that is synthesized from progesterone. It acts as a positive allosteric modulator of GABAA receptors at nM concentrations and of GABAC receptors at μM concentrations. Allopregnanolone displays effects similar to other GABAA receptor potentiators such as benzodiazepines, including potent anticonvulsant, anxiolytic, and sedative activity.