When T-mag first broke the news on vitex, it was mentioned that it blocked estrogen without causing transcription. At the time, it seemed preliminary. But in the Biotestedge description of M it primarily states that it lowers prolactin levels but does not mention any anti-estrogen effects (although the other ingredients do). Does anyone know if vitex is actually anti-estrogenic?
In the studies I have reviewed vitex actually acted as a weak agonist in breast cancer cells without an antagonist effect (J Agric Food Chem 2001 May;49(5):2472-9). The only thing vitex has been shown to do is reduce prolactin levels in both men (Exp Clin Endocrinol Diabetes 1996;104(6):447-53) and women (Arzneimittelforschung 1993 Jul;43(7):752-6). It has also been shown to reduce PMS symptoms in women (Arch Gynecol Obstet 2000 Nov;264(3):150-3). Prolactin has a negative effect on LH and FSH release and subsequently testosterone. However, in the study I mentioned above vitex had no effect on LH, FSH, or testosterone levels. The study was only 14 days so a longer-term study might show an effect. Vitex has also been shown to lack effects on LH and FSH release in rat pituitary cells ( Exp Clin Endocrinol 1994;102(6):448-54). I have heard that an obscure German study showed that vitex increases LH but I have not been able to obtain a reference.