Protopanaxadiol (PPD) is an organic compound that is an aglycone of ginsenosides, a group of steroid glycosides.

One study suggests it has rapid, non-genomic effects on endothelial cells, binding to the glucocorticoid and oestrogen beta receptors.

[3] Shanghai Innovative Research Center of Traditional Chinese Medicine (SIRC-TCM) is trying to develop an antidepressant based on this substance under the brand name Yoxintine.

[5] A pharmacokinetic study done on phase IIa human volunteers reports the relationship between oral dose and blood plasma concentration, but no data is given for oral bioavailbility, half life, or volume of distribution.

[6] In rats, the oral bioavailbility is about 48% and the half-life is 6.25 hours when given as an extract containing both PPD and PPT.