What Are the Side Effects of a Female Taking Testosterone?

Testosterone use in women and people assigned female at birth can trigger a range of side effects, from relatively mild skin changes like acne and excess hair growth to potentially permanent shifts in voice pitch. The specifics depend heavily on dose, duration, and the reason for taking it: a postmenopausal woman using a low-dose patch for sexual dysfunction faces a different risk profile than someone on higher doses for gender-affirming care. What follows is a walk through the most common and clinically meaningful effects, what tends to be reversible, and where the science still has gaps.

Skin and Hair Changes Are Usually the First to Show Up

Acne and increased body or facial hair (hirsutism) are the most frequently reported androgenic side effects in women taking testosterone, regardless of dose or indication. A review of safety data in postmenopausal women identified these two as the major adverse reactions associated with testosterone treatment.¹ Both effects are driven by the same mechanism: testosterone stimulates sebaceous glands (producing oilier skin and breakouts) and converts fine vellus hairs into thicker terminal hairs on the chin, upper lip, chest, and abdomen.

For women on low, physiological-range doses, acne and hirsutism tend to be mild and often manageable with topical treatments or dose adjustments. At higher doses, such as those used in gender-affirming testosterone therapy, hair growth can become substantial and acne more stubborn. Facial hair growth and male-pattern body hair distribution are considered partially irreversible: if you stop testosterone, new hair growth slows, but hair follicles that have already converted to terminal hairs do not always revert. On the other hand, acne generally improves once the dose is lowered or discontinued.

Voice Deepening and Why It Can Be Permanent

One of the side effects that catches many women off guard is a change in voice. Testosterone thickens the vocal cords and triggers growth in the surrounding laryngeal structures, including the thyroarytenoid muscle, the mucosal lining, and the laryngeal cartilage itself.² The result is a lower speaking pitch. A multi-institutional case series found that women treated with androgen supplementation experienced a measurable drop in their fundamental frequency, and that even after stopping testosterone and undergoing voice therapy, the changes could be permanent.³

This is not just a concern at high doses. A controlled trial testing modest testosterone doses in women found that pitch dropped significantly even in groups receiving relatively low amounts, and that the degree of lowering tracked with rising testosterone blood levels.⁴ For women who rely on their voice professionally, or who simply do not want a permanent change in how they sound, this is worth discussing with a prescriber early on. Voice changes tend to develop gradually and can be subtle at first, which means they sometimes progress before a person realizes what is happening.

Menstrual Disruption and Fertility

Testosterone suppresses the hormonal signals that drive the menstrual cycle, and most transmasculine people on adequate testosterone doses reach amenorrhea (absence of periods) within about six months.⁵ For women using low-dose testosterone for other reasons, periods may become irregular rather than stopping entirely. In either case, the absence of a period does not guarantee that ovulation has ceased. Reports of unplanned pregnancies among people on testosterone make clear that ovulation is not reliably suppressed in everyone.⁶ Testosterone is not a contraceptive, and anyone who could become pregnant and does not want to should use a separate method.

The longer-term picture for fertility is less clear. Testosterone appears to affect the ovaries, uterus, and fallopian tubes, but whether those changes are fully reversible remains an open question. Some people have successfully become pregnant or undergone assisted reproduction after discontinuing testosterone, but researchers caution that these outcomes cannot be assumed for everyone.⁷ If future fertility matters to you, discussing egg freezing or other preservation options before starting testosterone is a practical step.

Vaginal and Genital Changes

Testosterone shifts the local tissue environment of the vaginal canal. While some people notice increased lubrication, the more commonly reported experience is vulvovaginal atrophy: dryness, thinning of the vaginal walls, and increased susceptibility to tearing and bleeding during penetration. These effects are especially well documented in transmasculine individuals on long-term therapy. A study examining clitoral blood flow and genital changes in women treated with testosterone found an increase in clitoral area, though it did not reach statistical significance over six months.⁸ Clitoral growth, unlike vaginal dryness, tends to be more persistent and may not fully reverse after stopping treatment.

Vaginal dryness is often manageable with topical estrogen creams or moisturizers, and many clinicians prescribe these alongside testosterone when needed. The discomfort is worth raising with a provider rather than enduring silently, since it can affect sexual health and overall quality of life.

Cholesterol, Blood Counts, and Heart Health

Testosterone’s effect on blood lipids is one of the more consistently documented metabolic side effects. A review of studies in postmenopausal women found that testosterone alone significantly lowered HDL cholesterol (the “good” kind), while LDL cholesterol remained unchanged. When testosterone was combined with estrogen, total and LDL cholesterol dropped, but HDL still took an unfavorable hit, likely driven by the testosterone component.⁹ A separate study of transmasculine individuals on gender-affirming hormone therapy found that HDL cholesterol dropped by about 16% within the first two to ten months.¹⁰

Whether these lipid shifts actually translate into more heart attacks or strokes is harder to pin down. Lower HDL is a recognized cardiovascular risk factor in general populations, but clinical studies of women on testosterone have not yet demonstrated a clear increase in cardiovascular events. The evidence is reassuring in the sense that no major adverse cardiac outcomes have been reported even in long-term studies of people taking supraphysiological doses, but the reassurance is limited by the relatively small size and short follow-up of most existing trials.¹¹

Erythrocytosis, an increase in red blood cell production, is another side effect that shows up in blood work. In one cohort of transmasculine individuals on testosterone, 49 people were diagnosed with erythrocytosis over the course of monitoring.¹² Higher red blood cell counts thicken the blood, which can raise the risk of clots. This is why routine blood work, including a complete blood count and hematocrit, is standard practice during testosterone therapy. If levels climb too high, clinicians typically adjust the dose or the interval between injections.

Insulin Resistance

Testosterone can nudge the body toward insulin resistance, meaning cells become less responsive to insulin’s signal to absorb glucose. A study in postmenopausal women found that three months of testosterone treatment reduced insulin-stimulated glucose uptake by roughly 20%, whether testosterone was given alone or alongside estrogen.¹³ Research in postmenopausal women more broadly has found that free testosterone levels tend to positively correlate with measures of insulin resistance.¹⁴

This relationship is also visible in conditions involving naturally elevated androgens. In women with polycystic ovary syndrome, elevated testosterone levels are associated with higher baseline insulin, reduced insulin binding on cells, and blunted responses to blood sugar swings.¹⁵ For someone already at risk for type 2 diabetes, such as those with a family history or who carry excess weight, the metabolic nudge from testosterone therapy is worth monitoring. Periodic fasting glucose or hemoglobin A1c checks can catch meaningful changes early.

Sleep Apnea Risk

Obstructive sleep apnea is already more common in men than in women, and testosterone appears to be part of the reason. In transmasculine individuals, researchers found that the number of people reporting snoring increased after starting testosterone therapy, supporting the idea that exogenous testosterone raises the risk of sleep-disordered breathing.¹⁶ The mechanism ties back to the structural changes in the throat and airway. The same thickening and enlargement of laryngeal tissue that deepens the voice can also narrow the upper airway and make it more collapsible during sleep.²

If you are starting testosterone and notice new or worsening snoring, daytime fatigue, or waking up gasping, a sleep study is worth requesting. Untreated sleep apnea carries its own cascade of cardiovascular and metabolic risks, so catching it early matters.

Bone Density

This is one area where testosterone’s effects tend to be favorable rather than harmful. A case series of female-to-male transsexuals on supraphysiological testosterone found a significant increase in bone mineral density at the hip of about 7.8% over two years, with bone density at the spine maintained.¹⁷ Observational data in postmenopausal women have also found a positive association between serum testosterone levels and lumbar spine bone density, though the relationship may flatten out or reverse beyond a certain concentration.¹⁸

For postmenopausal women, who are at heightened risk for osteoporosis, this bone-protective effect is sometimes cited as a potential benefit of testosterone therapy. That said, the bone gains documented so far come from small studies, and testosterone is not approved or recommended as a primary treatment for osteoporosis. The takeaway is that bone health is generally not a concern during testosterone use, and may modestly improve.

Testosterone and Pain Sensitivity

A less commonly discussed effect of testosterone involves pain perception. Research in men has found that those with lower testosterone concentrations have lower pain thresholds and reduced pain tolerance compared to men with normal levels, with free testosterone levels correlating positively with tolerance.¹⁹ In female mice, testosterone treatment appeared to protect against the development of widespread muscle pain by modulating serotonin signaling in a brainstem region involved in pain processing. Testosterone-treated female mice showed lower expression of the serotonin transporter and higher expression of a serotonin receptor in that region, effectively keeping pain-related signaling closer to normal.²⁰

This area of research is still early, and the clinical implications for women on testosterone therapy are not established. But it raises an interesting possibility: some women who report feeling “tougher” or less bothered by chronic aches after starting testosterone may be experiencing a genuine neurochemical shift, not just a placebo effect. Whether this protective effect is meaningful for conditions like fibromyalgia or chronic pelvic pain is a question researchers are still working through.

Dose Makes the Difference

Many of the side effects described above are dose-dependent, and the distinction between physiological and supraphysiological dosing matters enormously. A review examining safety data from female-to-male transsexuals treated with pharmacological (high) doses for extended periods found no significant serious adverse effects, which led the authors to conclude that treatment at lower, physiological doses for conditions like sexual dysfunction should produce even fewer and milder side effects.¹¹ One study of women with sexual dysfunction treated at physiological testosterone levels for six months reported no hirsutism, acne, or other adverse events at all.⁸

The practical lesson is that a woman using a low-dose testosterone cream or patch under medical supervision for low libido is in a fundamentally different situation from someone self-administering injectable testosterone at doses designed to produce masculinizing effects. Blood levels, monitoring frequency, and the likelihood and severity of side effects all scale with the dose. Self-dosing without lab monitoring is where the most avoidable problems occur, because testosterone blood levels can climb well above the intended range without obvious symptoms until changes like voice deepening or clitoral growth have already become difficult to reverse.

What Reverses and What Stays

A common question for anyone considering testosterone is which changes will go away if they stop. The answer splits along predictable lines. Effects driven by ongoing hormone levels, like oily skin, acne, mood shifts, menstrual suppression, and altered cholesterol, tend to reverse within weeks to months of discontinuation. Erythrocytosis corrects as red blood cell turnover brings counts back to baseline. Insulin sensitivity generally returns to pre-treatment levels.

Structural changes are another story. Voice deepening involves physical remodeling of the vocal cords and laryngeal cartilage, and while some modest recovery is possible with voice therapy, the pitch drop is often permanent.³ Facial hair follicles that have been activated by androgens do not necessarily go dormant again. Clitoral enlargement may partially regress but often does not return to pre-treatment size. These are the changes that clinicians emphasize discussing before treatment begins, because they represent a line that cannot easily be uncrossed.

For anyone starting testosterone, the single most useful habit is consistent lab monitoring and honest communication with a prescriber. Blood work catches rising hematocrit, shifting lipids, and supraphysiological hormone levels before they cause problems. And paying attention to early signs of voice change or unwanted hair growth gives you the chance to adjust course while the changes are still modest.