Product Description per second website (reference to fin bolded):
Allopregnanolone (3α-hydroxy-5α-pregnan-20-one or 3α,5α-tetrahydroprogesterone; also abbreviated as THP or THPROG)
is a prototypic neurosteroid present in the blood and also the brain. It is a metabolite of progesterone and potent modulator of GABAA receptors.
While allopregnanolone, like other GABAA receptor active neurosteroids such as allotetrahydrodeoxycorticosterone (3α,21-dihydroxy-5α-pregnan-20-one; THDOC), positively modulates all GABAA receptor isoforms, those isoforms containing δ-subunits exhibit greater magnitude potentiation.
Allopregnanolone has pharmacological properties similar to other positive modulators of GABAA receptors, including anxiolytic and anticonvulsant activity.[1]
The biosynthesis of allopregnanolone starts with the converting of progesterone into 5α-dihydroprogesterone by 5α-reductase type I. After that, 3α-hydroxysteroid oxidoreductase isoenzymes (also referred to as 3α-hydroxysteroid dehydrogenase) converts this intermediate into allopregnanolone.
Anxiety and depression are common side effects of 5α-reductase inhibitors such as finasteride and dutasteride, and they are believed to be caused, in part, by the prevention of the endogenous production of allopregnanolone.
The 5-epimer of this compound (pregnanolone; 3α-hydroxy-5-pregnan-20-one) has similar properties to allopregnanolone, and the 3-methyl analogue, ganaxolone, is under development to treat epilepsy and other conditions.
Allopregnanolone may serve as an endogenous anticonvulsant and play a role in catamenial epilepsy.[2]