Does Vitex Increase Milk Supply?
Despite its longstanding use as an herb to increase breast milk supply, there is no real evidence that vitex actually is useful for this purpose. Low doses can increase levels of the hormone prolactin (which, theoretically, might increase breast milk supply), but high doses have the opposite effect and can actually decrease the supply. Changes in supply (in either direction) are probably most likely in the early phases of breastfeeding just after childbirth, when hormones play a larger role in breast milk production.
