Norgestrel is a progestogen, or an agonist of the progesterone receptor.[1] The biological activity of norgestrel lies in the levo enantiomer, levonorgestrel, whereas the dextro isomer is inactive.[4] As such, norgestrel is identical in its hormonal activity to levonorgestrel except that it is half as potent by weight.[4] Levonorgestrel, and by extension norgestrel, have some androgenic activity, but no estrogenic, antimineralocorticoid, or glucocorticoid activity.[4]