Vitex agnus-castus (often referred to as Vitex) is a shrub that originates from the Mediterranean. Some of the earliest scientific studies on Vitex for women's problems date back to 1954 in Germany. Vitex has been shown to help alleviate premenstrual symptoms, cycle irregularities and adverse menopausal symptoms.

Vitex berries are used in the manufacture of the herbal extract and contain a wide range of active compounds, including flavonoids and a group of compounds referred to as iridoids, which include aucubin and agnuside. Modern research has shown that the action of Vitex is at the highest level of hormonal control: the pituitary gland in the brain. Here, it is thought that Vitex mimics an important neurotransmitter referred to as dopamine, which helps to normalise the output of gonadotrophins, which control sex hormones.