Testosterone therapy in women can cause a range of side effects, from mild skin changes like acne to more significant shifts in cholesterol levels and body composition. The specific effects depend heavily on the dose: women prescribed low, physiological doses for conditions like low sexual desire experience far fewer and milder changes than those taking higher doses for gender-affirming care. Understanding which effects are temporary and which can become permanent is key to making informed decisions about treatment.
Why Women Take Testosterone
The most well-established medical reason for prescribing testosterone to women is hypoactive sexual desire disorder (HSDD) in postmenopausal women. A 2019 global consensus statement found that at doses mimicking normal premenopausal levels, testosterone therapy increased satisfying sexual events by roughly one per month and improved desire, arousal, and orgasmic function compared to placebo. International guidelines are clear that blood testosterone levels should not exceed those seen in healthy young women when treating HSDD.
Women also take testosterone as part of gender-affirming hormone therapy, typically at much higher doses designed to produce masculinizing effects. The side effect profiles for these two uses overlap but differ significantly in intensity. Most of the research on pronounced side effects comes from studies of higher-dose, gender-affirming therapy.
Skin and Hair Changes
Acne is one of the earliest and most common side effects. Testosterone stimulates oil production in the skin, and breakouts often appear within the first few weeks of treatment. At low therapeutic doses, this is usually mild and manageable. At higher doses, acne can be more persistent and severe, sometimes requiring dermatological treatment.
Increased body and facial hair growth (hirsutism) is another androgenic effect. Fine vellus hairs on the face, chest, abdomen, and back can gradually become thicker and darker. This tends to develop over months and progresses slowly. At low doses used for HSDD, noticeable hirsutism is uncommon, but it remains one of the effects women report being most concerned about.
Scalp hair loss is widely assumed to be a risk, but the evidence is more nuanced than expected. A study of 285 women receiving subcutaneous testosterone implants, published in the British Journal of Dermatology, found that no patient reported hair loss as a side effect of treatment. In fact, among the 27% of women who had hair thinning before starting therapy, 63% reported hair regrowth. Women with lower baseline testosterone levels were more likely to have thinning hair before treatment, suggesting that testosterone deficiency itself may contribute to hair loss. That said, at supraphysiological doses, the conversion of testosterone to its more potent form can still drive hair thinning in genetically susceptible individuals.
Voice and Genital Changes
Two effects stand out because they are largely irreversible: voice deepening and clitoral enlargement. Testosterone thickens the vocal cords, gradually lowering pitch. At low therapeutic doses, significant voice changes are rare, but at higher doses used in gender-affirming care, deepening typically becomes noticeable within months and does not fully reverse if therapy is stopped.
Clitoral growth follows a similar pattern. Research in a mouse model found that after six weeks of testosterone treatment and subsequent cessation, nearly all reproductive changes reversed within a week of stopping therapy. Hormone levels, ovarian follicle counts, and menstrual cycling all returned to normal. The one exception was clitoral size, which remained significantly larger even after testosterone levels dropped. This finding aligns with clinical observations in humans: clitoral tissue growth tends to persist.
Cholesterol and Heart Health
Testosterone shifts lipid levels in a less favorable direction. Studies of transmasculine individuals on gender-affirming doses show consistent patterns within the first two to ten months of therapy: LDL (“bad”) cholesterol rises by about 13%, HDL (“good”) cholesterol drops by 10 to 17%, and triglycerides increase by 26 to 37%. These changes in blood fats begin appearing around four weeks and typically reach their peak at six to twelve months.
At the lower doses prescribed for HSDD, lipid changes are milder, but the direction of change is the same. For women with existing cardiovascular risk factors like high blood pressure, smoking, or a family history of heart disease, even modest shifts in cholesterol balance deserve monitoring. Long-term cardiovascular outcomes data for women on testosterone are still limited, which is one reason guidelines recommend keeping doses as low as possible.
Red Blood Cell Changes
Testosterone stimulates red blood cell production, a process called erythropoiesis. This effect becomes measurable around three months and peaks at nine to twelve months. In most women, the increase is modest and clinically insignificant. A Mount Sinai study of transmasculine individuals on full masculinizing doses found that only 8.4% developed a hematocrit (the proportion of blood made up of red cells) above 50%, and less than 1% reached the 54% threshold where intervention like therapeutic blood draws is typically recommended.
At the low doses used for HSDD, clinically significant red blood cell elevation is rare. Still, periodic blood monitoring is standard practice to catch any upward drift early.
Mood and Mental Health Effects
Concerns about testosterone causing aggression or irritability in women are common, but the clinical picture is more positive than many expect. A pilot study of peri- and postmenopausal women treated with transdermal testosterone found that 77% reported irritability at baseline before starting treatment. After therapy, 47% of women reported improved mood overall, with moderate-to-severe mood symptoms decreasing by 37%. Irritability scores dropped significantly, and improvements in mood were actually greater than improvements in cognitive symptoms like brain fog and memory problems.
This makes sense in context: many women prescribed testosterone are dealing with hormonal deficiency that itself causes low mood, anxiety, and irritability. Restoring levels to a normal range often improves these symptoms rather than worsening them. At higher doses, some women do report increased irritability or emotional intensity, though large-scale data on this are limited.
Menstrual and Fertility Effects
Higher doses of testosterone suppress the menstrual cycle. Periods typically become irregular and eventually stop, a state called amenorrhea. This happens because testosterone disrupts the hormonal signaling that drives ovulation. At the low doses used for HSDD in postmenopausal women, this is irrelevant since menstruation has already ceased.
For premenopausal women, the key question is whether fertility returns after stopping testosterone. The mouse model data are encouraging: after testosterone cessation, normal cycling resumed within one week, with no detectable differences in follicle counts, ovarian function, or hormone levels compared to untreated controls. Levels of estrogen, progesterone, and the hormones that regulate the menstrual cycle all returned to baseline. While animal models don’t translate perfectly to humans, clinical experience generally supports that menstrual cycles resume after discontinuing testosterone, though the timeline varies.
Breast Cancer Risk
One of the most persistent concerns about testosterone therapy in women is whether it increases breast cancer risk. A 2025 systematic review and meta-analysis of over 5,700 postmenopausal women followed for up to ten years found that testosterone therapy was not associated with increased breast cancer risk. In fact, the pooled data showed a statistically significant 41% reduction in breast cancer incidence among testosterone users compared to population-based cancer rates. The authors noted that while these findings suggest a possible protective effect, the studies were observational, so the results should be interpreted with caution.
When Effects Appear and How Long They Last
Side effects follow a fairly predictable timeline. Changes in sexual interest are among the earliest, appearing within three weeks and plateauing by six weeks. Mood improvements begin at three to six weeks, with maximum benefit arriving around 18 to 30 weeks. Body composition shifts, including changes in fat distribution and muscle mass, start at 12 to 16 weeks and stabilize between 6 and 12 months. Lipid changes begin at four weeks and peak at 6 to 12 months. Bone density improvements are detectable at six months and continue for at least three years.
If therapy is stopped, most metabolic and hormonal effects reverse as testosterone levels drop. Acne clears, menstrual cycles return, cholesterol levels normalize, and red blood cell counts come back down. The effects that tend to persist are structural ones: voice deepening, clitoral growth, and any facial or body hair growth driven by conversion of fine hairs to thicker terminal hairs (though hair growth may gradually thin after stopping). The degree of permanence depends on the dose and duration of therapy. Women on low-dose, short-term treatment for HSDD are far less likely to experience lasting changes than those on years of higher-dose therapy.