SERM
Also called Selective estrogen receptor modulator
A SERM (selective estrogen receptor modulator) is a medicine that binds to estrogen receptors and acts like estrogen in some tissues while blocking estrogen in others. Raloxifene (sold as Evista), for example, mimics estrogen in bone and blocks its effects in the breast. Tamoxifen blocks estrogen's action in breast tissue and is used in breast cancer care.
Clomiphene (sold as Clomid) is a mixture of two isomers, enclomiphene and zuclomiphene, which act on the estrogen receptor in opposite ways. Enclomiphene acts as an estrogen blocker. In the pituitary, blocking estrogen's braking signal leads to more luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which is why clomiphene and enclomiphene have been used off-label to treat low testosterone in men.
Why it matters after 45
Men in midlife meet this class when low testosterone comes from the pituitary signal rather than the testes, and fertility or the body's own production is a consideration. Women meet it after menopause, when raloxifene is used to prevent and treat osteoporosis, or in breast cancer care.
Where it comes up
- Enclomiphene ODTthe compounded preparation ACT 2 prescribes, and how it is monitored
- Enclomiphene vs Clomidhow the single isomer differs from the two-isomer mixture
- Enclomiphene and secondary hypogonadismthe kind of low testosterone this approach is aimed at
- TRT vs enclomiphenehow replacing testosterone differs from signaling the body to make more
Related terms
References
- MedlinePlus. Raloxifene. U.S. National Library of Medicine. https://medlineplus.gov/druginfo/meds/a698007.html
- MedlinePlus. Tamoxifen. U.S. National Library of Medicine. https://medlineplus.gov/druginfo/meds/a682414.html
- Saffati G, et al. Safety and efficacy of enclomiphene and clomiphene for hypogonadal men. Transl Androl Urol, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11491226/
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