Tamoxifen Citrate 20mg 50 Tablets Altamofen is a selective estrogen receptor modulator (SERM) useful in blocking estrogen receptors to reduce expression. Testosterone and many anabolics aromatise to estrogens. Tamoxifen blocks estrogen receptors to stop the estrogen from increasing fat storage, water weight, & emotional liability. Tamoxifen is useful after androgen therapy to block estrogen while waiting for the body to restart testosterone production. For male breast tissue growth: 40mg per day For male estrogen management: 10mg-40mg per day