Glossary · Treatments

SERM (Selective Estrogen Receptor Modulator)

Also called: Selective Estrogen Receptor Modulator.

Definition: SERMs are compounds that act as estrogen receptor agonists in some tissues and antagonists in others. Examples include tamoxifen (breast antagonist, uterine agonist), raloxifene (bone agonist, breast antagonist), and ospemifene (vaginal agonist, breast antagonist). SERMs allow tissue-selective benefits without full estrogen agonism.

Detailed definition

Selective estrogen receptor modulators (SERMs) are non-steroidal compounds that bind estrogen receptors and produce tissue-specific agonist or antagonist effects depending on local cofactors and receptor isoforms. Tamoxifen is an antagonist in breast tissue (used for breast cancer) and a partial agonist in endometrium (small endometrial cancer risk). Raloxifene (Evista) is FDA-approved for postmenopausal osteoporosis prevention and treatment, and reduces breast cancer incidence in high-risk women — agonist on bone, antagonist on breast and endometrium. Ospemifene is an agonist on vaginal tissue (treating GSM) with breast-antagonist activity. Bazedoxifene is combined with conjugated estrogens in Duavee (a tissue-selective estrogen complex, TSEC) for combined HRT in women with a uterus without requiring traditional progestogen — bazedoxifene provides endometrial protection. SERMs typically share the oral-route VTE risk of estrogen.

Why it matters in menopause

SERMs offer mechanism-specific options for women who need targeted estrogen-pathway intervention without full systemic estrogenization. Raloxifene for osteoporosis with breast cancer risk reduction, ospemifene for GSM in women avoiding estrogen, and Duavee for women who cannot tolerate progestogens are the three main menopause-relevant uses.

Sources

External references: Wikipedia.

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