Vitex, also known as Vitex agnus-castus or chaste tree, has a long history of use in traditional herbal medicine, especially for supporting hormonal balance in women. Traditionally, it has been used to address symptoms of premenstrual syndrome (PMS), irregular menstrual cycles, and other menstrual disorders. The mechanism often cited is its action on the pituitary gland, potentially influencing levels of luteinizing hormone (LH) and, consequently, progesterone production.

Scientific evidence supports some of these traditional uses, albeit with moderate strength. Several randomized controlled trials and meta-analyses indicate that Vitex can reduce PMS symptoms, including breast tenderness, mood swings, and headaches. A systematic review published in Planta Medica (2013) concluded that Vitex extracts are more effective than placebo in alleviating PMS symptoms, with few adverse effects. Additional studies suggest benefits for mild hyperprolactinemia and cycle irregularity.

However, the overall quality of evidence is moderate due to variability in study methodologies, small sample sizes, and differences in extract formulations. Most research focuses on women of reproductive age, and there is limited data on efficacy for other hormonal issues or for use in men. Despite these limitations, current evidence justifies considering Vitex as a supportive agent for the "Hormones" body system, especially in the context of PMS and menstrual irregularities.