Cimetidine for Reducing Libido in Women
There is extremely limited evidence for cimetidine's effects on female libido, with only one published case report from 1983 documenting depression and loss of libido in a woman taking cimetidine. 1
Available Evidence in Women
The literature on cimetidine's sexual effects is almost entirely focused on men, with minimal data in women:
A single case report exists describing a healthy young woman who developed marked depression and loss of libido while taking cimetidine, with prompt resolution after discontinuation. 1 This represents the only documented evidence of cimetidine affecting female sexual function.
The mechanism in this case could not be explained by the accepted theories of cimetidine's CNS effects at the time, and depression had not been previously reported as an adverse effect. 1
Evidence in Men (Not Applicable to Women)
The bulk of research demonstrates cimetidine's antiandrogenic effects specifically in males:
Cimetidine inhibits estradiol 2-hydroxylation in men, reducing it from 31.7% to 19.7% after two weeks of treatment (800 mg twice daily), while simultaneously increasing serum estradiol concentrations by approximately 20%. 2 This mechanism explains gynecomastia and sexual dysfunction in male patients.
Cimetidine can block testosterone synthesis through a reversible defect in 17-beta-hydroxysteroid dehydrogenase, causing low testosterone levels and sexual dysfunction in men. 3
The FDA label confirms reversible impotence in men with pathological hypersecretory disorders receiving cimetidine, particularly at high doses for at least 12 months. 4
Cimetidine demonstrates weak antiandrogenic effects in animal studies, manifested as reduced prostate and seminal vesicle weights. 4
Critical Limitations
The mechanism of action differs fundamentally between sexes: Cimetidine's sexual side effects in men result from antiandrogenic effects and altered estrogen metabolism—pathways that would not be expected to reduce libido in women. 2, 3
No controlled trials exist examining cimetidine for intentional libido reduction in women.
The single case report cannot establish causation or predict reproducibility. 1
Clinical Implications
Cimetidine should not be considered a viable option for reducing female libido given:
- The absence of mechanistic rationale for efficacy in women
- Only one case report of uncertain causality 1
- The availability of FDA-approved medications for female sexual dysfunction (flibanserin, bremelanotide) that have been properly studied 5, 6
- Potential for significant adverse effects including confusional states, particularly in patients over 50 years or those with liver/renal disease 4
If libido reduction is clinically indicated in women, consider SSRIs/SNRIs which are known to cause reduced libido and anorgasmia as side effects, though this represents off-label use. 7