Tamoxifen is a selective estrogen receptor modulator that is used as a drug to treat breast cancer in pre-menopausal and post-menopausal women. Tamoxifen was developed by ICI Pharmaceuticals (now AstraZeneca) and causes competitive inhibition of estrogen receptors and stimulation of progesterone receptors.
Nolvadex is a brand name for tamoxifen, which is also a SERM. It has been approved in the United States since 1962 and is prescribed for the treatment of breast cancer, infertility, and also for the prevention of gynecology. Like Clomid, Nolvadex blocks the interaction of estrogen with the pituitary gland. When estrogen interacts with the pituitary gland, less luteinizing hormone (LH) and follicle stimulating hormone (FSH) are produced. Leads to a decrease in testosterone.
One study showed that a dose of ten to 20 milligrams of tamoxifen, also known under the brand name Nolvadex, when taken daily, reduced gynecomastia in 90 percent of cases within three to nine months.
If the estrogen level is increased significantly more than is naturally the case due to the exogenous intake of anabolic steroids, a higher dose of tamoxifen than described above will often be necessary in order to compete with the estrogens for the receptors. At least if the treatment of gynecomastia with tamoxifen is to take place during the cure. An amount of 30 to 40 milligrams daily should be sufficient in most cases.