Vitex
Best for
More regular menstrual cycles
Large effect, needs confirmation 5.8 mg/day 12 weeks 1 study, n=60 #1 of 4 studied
- 3 papers
- 3 of 21 outcomes
- 2 positive
Vitex shows a large effect on period predictability, but the finding needs confirmation because evidence across other outcomes remains early and limited.
Median effective dose, most-studied outcomes
- Make menstrual cycles more predictable 5.8 mg 12 wk
- Support more regular ovulation with PCOS 5.8 mg 12 wk
What vitex actually does
Menstrual regularity means periods arrive at a predictable interval. 41428718
Breast pain can cause tenderness or aching that makes clothing, sleep, and touch uncomfortable. 36446563
PCOS can disrupt ovulation, making it harder to predict when an egg is released. 41428718
| Outcome | Effect | Evidence | Dose | Time | Rank |
|---|---|---|---|---|---|
| Worth watching 2 | |||||
| More regular menstrual cycles Large effect, needs confirmation Menstrual regularity means periods arrive at a predictable interval. | | 1 RCT 1 papers · n=60 | 5.8 mg | 12 wk | #1 /4 |
| Ease breast pain Promising early signal Breast pain can cause tenderness or aching that makes clothing, sleep, and touch uncomfortable. | | 1 meta-analysis 1 papers · n=— | — | — | #2 /5 |
| Early research 1 | |||||
| Help ovulation in PCOS Not enough research PCOS can disrupt ovulation, making it harder to predict when an egg is released. | | 1 RCT 1 papers · n=60 | 5.8 mg | 12 wk | — |
Effect tiers come from native-unit MCID where available, Cohen's d otherwise.
Dose, timing & forms
How much
The clearest signal comes from a 5.8 mg daily oral dose used for 12 weeks in a study of menstrual timing. The same daily amount also appears in early ovulation research in people with PCOS, but that finding is much less certain and needs replication before it guides expectations. 1
When and how long
The available protocols use Vitex consistently every day for months, not as an occasional remedy when symptoms show up. They do not establish a best time of day, so choose a time you can stick with and follow the product-specific directions. 1
Forms & standardisation
The dose evidence does not identify enough product detail to treat all Vitex supplements as interchangeable. Look for the exact species, the plant part used, and any extract ratio or standardization on the label. Most traditional and regulatory information concerns chaste tree fruit, not an unspecified Vitex ingredient. 1
Studied range, by outcome
| Outcome | Studied range | Median effective | Duration | Evidence |
|---|---|---|---|---|
| Make menstrual cycles more predictable | 5.8 mg | 5.8 mg | 12 wk | 1 paper 1 sig. endpoint |
| Support more regular ovulation with PCOS | 5.8 mg | 5.8 mg | 12 wk | 1 paper 1 sig. endpoint |
Adverse events and drug interactions
Safety events
What this is and how it works
- One study (n=60) reported more predictable periods, but no effect size or noticeable-change threshold was provided.1
- Three papers reviewed here span 21 outcomes, including an early signal for cycle-related breast tenderness.
- Evidence applies to Vitex agnus-castus fruit preparations, with species and plant-part labeling important.1
Vitex is a botanical name that covers a group of plants. In supplements, it often refers to chaste tree, usually made from the plant's fruit, but a label that says only “Vitex” leaves important details unanswered. Look for the full species name and plant part before assuming two products are comparable. 1
Research on chaste tree focuses on brain dopamine signals that influence prolactin release, a hormone involved in reproductive signaling. Think of prolactin as one musician in an orchestra: when it plays too loudly, it can throw off the timing of the whole group, while dopamine acts like the conductor asking it to quiet down. 1
Bottom line
Vitex is worth watching if unpredictable cycles are your main reason for considering it and you are comfortable with early evidence. The menstrual-timing result looks promising, but it rests on limited research, and the PCOS ovulation signal remains too thin for confident advice. Skip vague labels that do not name the Vitex species and plant part. 1
Common questions
Does Vitex make periods more regular?
Can Vitex support ovulation in PCOS?
What side effects can Vitex cause?
Sources
Sources
Generated August 27, 2026