Testosterone Supplementation Does Not Appear to Directly Shrink Fibroids, But May Promote Fibroid-Associated Changes in the Myometrium
Based on available evidence, testosterone supplementation in women is not an established treatment for reducing fibroid size and may actually induce myometrial changes similar to those seen in fibroid-bearing uteri.
Current Evidence on Testosterone and Uterine Fibroids
The provided guidelines on fibroid management 1, 2, 1, 2 comprehensively review medical therapies for uterine fibroids but notably do not include testosterone as a treatment option. The established medical approaches focus on:
- First-line: Oral contraceptives, progestin-containing IUDs, tranexamic acid 2
- Second-line: GnRH agonists and antagonists (which reduce fibroid volume by 40-50% through estrogen suppression) 2
- Emerging: Selective progesterone receptor modulators like ulipristal acetate 1
The pathophysiology of fibroids centers on estrogen and progesterone signaling 1, with progesterone and its receptors being essential for fibroid growth and proliferation. Testosterone is not part of the established hormonal framework for fibroid development or treatment.
Concerning Research Findings
Recent research suggests testosterone may have adverse effects on the myometrium:
A 2025 study found that myometrial tissue from testosterone-treated patients (for gender dysphoria) showed transcriptomic and DNA methylation profiles that clustered with fibroid-bearing myometrium rather than normal myometrium 3. The study identified 1,321 differentially expressed genes between testosterone-treated and normal myometrium, with upregulation of fibroid-associated genes including TGFβ3, CCND1, SERPINE1, and FGFR1.
A 2016 prospective study of female-to-male patients on testosterone found fibroids or hypertrophic myometrium in 58% of patients 4, with sustained androgen receptor expression in the myometrium (69%) and persistent Ki67 proliferative markers.
A 2019 multicenter case series of 94 transmasculine persons on testosterone showed active endometrium persisted in 69.1% despite amenorrhea, with one case of complex hyperplasia 5.
Safety Considerations from FDA Labeling
The FDA labeling for testosterone explicitly states it is contraindicated in pregnant women due to teratogenic effects 6. In animal studies, testosterone exposure resulted in structural impairments of reproductive tissues in female offspring, including intrauterine growth retardation and reduced ovarian reserve 6.
Testosterone gel is not indicated for use in women 6, and the 2019 Global Consensus Statement on testosterone therapy for women only supports its use for hypoactive sexual desire disorder (HSDD) in postmenopausal women 7—not for fibroid management.
Clinical Recommendation
Do not use testosterone supplementation to treat uterine fibroids. The evidence suggests:
- No therapeutic benefit: Testosterone is absent from all major fibroid management guidelines
- Potential harm: Emerging data indicate testosterone may induce fibroid-like myometrial changes and promote proliferative activity
- Established alternatives exist: GnRH agonists/antagonists effectively reduce fibroid volume by 40-50% 2, and selective progesterone receptor modulators show promise for both bleeding control and fibroid shrinkage 1, 2
For Patients Requiring Testosterone for Other Indications
If a woman with fibroids requires testosterone therapy for an approved indication (e.g., HSDD in postmenopausal women 7), close monitoring is warranted:
- Baseline pelvic ultrasound to document fibroid size
- Serial imaging every 6-12 months to assess for fibroid growth or new development
- Prompt evaluation of any abnormal uterine bleeding
- Consider alternative fibroid management strategies if symptoms worsen
The association between elevated androgens (as seen in PCOS) and increased fibroid risk further supports caution with exogenous testosterone administration in women with or at risk for fibroids 3.