Raloxifene

Hormonal / PCT

Also known as: Evista, Raloxifene HCl, Keoxifene

Selective Estrogen Receptor ModulatorsResearch phase: FDA-approvedRegulatory: FDA-approved for osteoporosis prevention/treatment (1997) and invasive breast cancer risk reduction (2007). Available by prescription as Evista.

Mechanism

Raloxifene is a second-generation SERM FDA-approved for osteoporosis prevention and treatment in postmenopausal women, and for breast cancer risk reduction. Unlike tamoxifen, it does not stimulate the uterine lining, giving it a better safety profile for long-term use. In the performance community, it is sometimes preferred over tamoxifen for gynecomastia management.

Technical detail

Raloxifene is a benzothiophene-derived SERM that functions as an ER antagonist in breast and uterine tissue while acting as an ER agonist in bone. Its tissue selectivity derives from differential recruitment of coactivator (SRC-1, SRC-3) and corepressor (NCoR, SMRT) complexes depending on the cellular context. Unlike tamoxifen, raloxifene does not activate uterine ER-alpha, eliminating endometrial stimulation risk. The MORE and RUTH trials demonstrated 65-76% breast cancer risk reduction alongside vertebral fracture prevention. It has less potent effects on hypothalamic-pituitary ER antagonism compared to tamoxifen or clomifene.

Build a personalized protocol with Raloxifene →