Vitex (chasteberry)
Standardised dry fruit extract — specifically Ze 440 (20 mg/day) or BNO 1095, the two extracts that carry the positive double-blind trials. Generic 'chasteberry powder' has no comparable evidence and no standardisation.
Moderate
Some good studies, not many repeats
Moderate, not strong. The pooled RR is large with a CI comfortably clear of 1, and a separate review found all 8 eligible RCTs positive — but only 3 trials met double-blind placebo-controlled standards, the meta-analysts flagged incomplete reporting of the medication itself, and most trials come from the manufacturers of Ze 440 and BNO 1095. The hormonal activity also warrants a genuinely narrower recommendation than calcium.
Across 3 careful studies of 520 women, those taking it were about two and a half times as likely to get real relief from PMS as those on a placebo.
Women on standardised vitex were 2.57 times more likely to reach symptom response than on placebo (RR 2.57, 95% CI 1.52–4.35) across 3 double-blind RCTs in 520 women.
Diterpenes in the fruit bind pituitary dopamine D2 receptors, lowering prolactin and easing the prolactin-driven component of breast tenderness and luteal mood symptoms. It works on the hormonal axis, not on the autonomic luteal shift a wearable records.
People whose charted premenstrual burden is dominated by breast tenderness and irritability, and who have completed at least two logged cycles. Explicitly not indicated for people whose only finding is the normal luteal rise in RHR and skin temperature.
What to buy
- ✓Standardised dry fruit extract — specifically Ze 440 (20 mg/day) or BNO 1095, the two extracts that carry the positive double-blind trials. Generic 'chasteberry powder' has no comparable evidence and no standardisation.
- ✓20 mg/day of Ze 440 standardised extract, or the labelled dose of BNO 1095. Trials ran three consecutive cycles before assessing response.
- ✓Third-party tested (USP, NSF, Informed Sport)
- ✕Proprietary blends that hide the dose per ingredient
- ✕Unstandardised extracts with no active-compound percentage
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The best-selling and best-reviewed vitex. The trials ran three consecutive cycles before judging response, so give it three months before you decide anything.
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A standardised extract rather than ground berry. The positive double-blind trials all used standardised extracts — Ze 440 or BNO 1095 — not generic powder.
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Five and a half thousand ratings, the most-reviewed here. Vitex works on prolactin, not on the autonomic shift your wearable records — the chart may not move even if the symptoms do.
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See all on AmazonEvery result, next to the line that means no effect
Each diamond is a study's best estimate. The thin line shows how sure the study was: the shorter the line, the more certain the result.
- Likelihood of PMS symptom responserisk ratio vs placebo · Csupor 2019, Complement Ther Med, 3 RCTs, n=520+2.57+1.52 … +4.35
- Eligible RCTs reporting a positive resultof 8 trials · Cerqueira 2017, Arch Womens Ment Health+8.00[not given]
Each unit gets its own scale, so numbers are never mixed on one line. When a study gave no range, we leave it blank instead of inventing one.
3 studies over 18 years
The studies
- 1.Vitex agnus-castus in premenstrual syndrome: A meta-analysis of double-blind randomised controlled trialsComplementary Therapies in Medicine · 2019 · rct · 3 experiments · n = 520
RR 2.57 (95% CI 1.52–4.35) for symptom remission versus placebo. Ze 440 and BNO 1095 were consistently superior to placebo in subgroup analysis, but the authors warn most studies cannot serve as efficacy evidence because of incomplete reporting of the medication used.
- 2.Vitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic reviewArchives of Women's Mental Health · 2017 · rct · 8 experiments
All 8 included RCTs were positive for vitex in PMS or PMDD across three different preparations, and it was overall well tolerated. The authors flag substantial variability in diagnostic criteria and outcome instruments between studies.
- 3.Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled studyBMJ · 2001 · rct · 1 experiments · n = 178
The pivotal Ze 440 trial (20 mg/day over three cycles) and the primary source for the vitex dose recommendation. Its specific responder percentages could not be verified from an accessible full text — the pooled estimate from Csupor 2019 should be used as the quantitative figure instead.
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