Vitex agnus-castus (Chaste Tree)

Vitex agnus-castus contains diterpenes and flavonoids that modulate dopamine receptors to reduce prolactin secretion. This hormonal rebalancing effect alleviates PMS symptoms and regulates menstrual cycles.

Origin & History

Vitex agnus-castus, commonly known as chaste tree or chasteberry, is a flowering shrub native to the Mediterranean region and Central Asia. The medicinal preparation uses extracts from the dried fruit, which contains a complex mixture of bioactive compounds including flavonoids, iridoid glycosides, and essential oils. Clinical studies typically employ standardized extracts delivered as capsules or tablets at doses of 20-40 mg daily.

Historical & Cultural Context

Vitex agnus-castus is described as a popular herbal treatment in Anglo-American and European practice, predominantly used for female reproductive conditions. The common name 'chaste tree' reflects its traditional association with women's health, though specific historical uses are not detailed in the available research.

Health Benefits

• Reduces premenstrual syndrome (PMS) symptoms with moderate effect size (SMD: 0.67) based on meta-analysis of 6 RCTs with 718 participants
• Alleviates cyclic breast pain and tenderness, proven effective in 17 RCTs according to systematic review
• Normalizes menstrual cycles by reducing prolactin levels and increasing progesterone in women with latent hyperprolactinemia (double-blind RCT, n=52)
• Improves bleeding intensity (83.4%), frequency (79.2%), and menstrual pain (85.2%) based on real-world data
• Reduces menopausal symptoms including anxiety and vasomotor dysfunction compared to placebo (RCT evidence)

How It Works

Vitex agnus-castus contains diterpenes (particularly casticin and agnuside) that bind to dopamine D2 receptors in the anterior pituitary gland. This binding inhibits prolactin release, which helps normalize the luteinizing hormone to follicle-stimulating hormone ratio. The resulting hormonal balance reduces estrogen dominance and supports progesterone production during the luteal phase.

Scientific Research

Vitex has been evaluated in 12 randomized controlled trials for female reproductive disorders, with a meta-analysis of 6 RCTs (n=718) demonstrating moderate effectiveness for PMS. Clinical trials show efficacy within one menstrual cycle, with 91% responder rate by the third cycle in Japanese patients (n=69). A systematic review of 25 studies (17 RCTs) confirmed effectiveness for cyclic mastalgia, with Vitex proving noninferior to conventional treatments.

Clinical Summary

A meta-analysis of 6 randomized controlled trials with 718 participants demonstrated moderate effectiveness for PMS symptom reduction (SMD: 0.67). Systematic review of 17 RCTs confirms significant reduction in cyclic breast pain and tenderness. Most studies used standardized extracts providing 20-40mg daily for 3-6 menstrual cycles. Evidence quality is moderate, with some studies lacking proper blinding protocols.

Nutritional Profile

Vitex agnus-castus is a medicinal herb rather than a nutritional food source, so macronutrient and caloric content are not clinically relevant; however, its bioactive phytochemical profile is well-characterized. Key bioactive compounds include: iridoid glycosides (agnuside at approximately 0.4–0.6% dry weight of fruit extract, and aucubin), which are considered primary marker compounds used for standardization of commercial extracts; flavonoids including casticin (0.01–0.1% dry weight), vitexin, isovitexin, orientin, and luteolin, which contribute to dopaminergic and antiestrogenic activity; diterpenes including rotundifuran, vitexilactone, and clerodadienols, present at approximately 0.02–0.08% in fruit extracts, which demonstrate dopamine D2 receptor agonist activity linked to prolactin suppression; essential oils (0.5–1.0% in dried fruit) comprising 1,8-cineole, limonene, sabinene, and beta-caryophyllene; and alkaloids including viticin in trace amounts. The standardized extract Ze 440 (used in clinical trials) is typically standardized to 0.6% agnuside. Bioavailability data is limited but flavonoids such as casticin show moderate oral absorption with hepatic first-pass metabolism. No significant conventional macronutrients (protein, fat, carbohydrate), vitamins, or dietary minerals are present at nutritionally meaningful concentrations, as the herb is consumed in extract form at doses of 20–40 mg dried extract per day rather than as a food.

Preparation & Dosage

Standardized extract: 20-40 mg daily of dried fruit extract for 3 months. Specific products studied include Prefemin® (efficacy within one cycle), Strotan® capsules (20 mg daily), and Cyclodynon®/Mastodynon®. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitamin B6, Magnesium, Evening Primrose Oil, Dong Quai, Black Cohosh

Safety & Interactions

Common side effects include nausea, headache, gastrointestinal upset, and menstrual irregularities during initial weeks of use. May interact with dopamine agonists, antipsychotic medications, and hormonal contraceptives by altering prolactin levels. Contraindicated during pregnancy and breastfeeding due to hormonal effects. May interfere with in vitro fertilization treatments due to prolactin suppression.