Do trans females possess more testosterone than biological females?
Executive summary
Untreated transgender women generally have male-range testosterone prior to any medical transition [1]; however, most transgender women who undergo standard feminizing hormone therapy (GAHT) — and especially those who have orchiectomy (gonadectomy) — reach testosterone concentrations within or below typical cisgender female reference ranges [2] [3] [4]. That said, suppression is heterogeneous: a subset of treated trans women do not consistently suppress to female ranges, and sports-physiology studies warn that low measured testosterone does not erase all prior testosterone-driven advantages [2] [1] [5].
1. Baseline physiology: untreated trans women typically have higher testosterone
Before any gender‑affirming medical treatment, transgender women (assigned male at birth) have circulating testosterone concentrations characteristic of natal males, which are higher than typical female ranges; multiple reviews and descriptive papers describe that transition begins from these higher baseline male levels [1] [2].
2. Feminizing hormone therapy usually lowers serum testosterone into female ranges, often markedly
Clinical cohorts and systematic reviews report that initiating GAHT causes a steep decline in total testosterone, with many studies finding post‑treatment mean values within the cisgender female reference range and several cohorts reaching very low levels after gonadectomy [3] [6] [7]. Large multi‑center data and clinic series show that most treated trans women have testosterone values below about 2 nmol/L, and in some post‑gonadectomy cohorts levels are lower than those seen in premenopausal cisgender women [6] [4] [8].
3. Suppression is variable — a meaningful minority may not reach typical female ranges
Endocrinology reviews and cohort studies document heterogeneity: up to a quarter of trans women on feminizing regimens can have nonsuppressed testosterone for reasons ranging from regimen choice, pharmacokinetics, adherence, or individual biology, and some studies report subsets who remain above conventional female limits despite therapy [2] [1] [6]. Clinic data show that in the highest‑suppressing quartile measured testosterone can be brought into the female range reliably (example: steady‑state 27 ng/dL reported in one cohort), but other quartiles or regimens produce wider spread [7] [9].
4. Gonadectomy and adjunct anti‑androgens drive testosterone even lower — sometimes below cis female norms
When orchiectomy is performed or when potent androgen‑lowering drugs (GnRH agonists, certain antiandrogens) are added, studies report testosterone concentrations that fall to the lowest parts of female reference ranges or below, attributed to loss of gonadal production and lower bioavailable androgens — a pattern observed across multiple reports [3] [4] [2].
5. What "more testosterone" means for function and sport: hormone level is one piece, not the whole story
Even when serum testosterone is suppressed, longitudinal research on strength and performance indicates residual advantages in some measures for months to years after starting GAHT — for example, one study found trans women remained faster and stronger than female comparators up to two years after treatment despite testosterone suppression — and systematic reviews note that muscle mass and haemoglobin change over differing time courses and with interindividual variability [5] [10] [6]. Researchers and commentators therefore caution against equating current serum testosterone alone with elimination of physiological advantages accrued from prior exposure [1] [11].
6. Bottom line and limits of the reporting
Answering the narrow question: at baseline, trans women (assigned male at birth) have higher testosterone than cisgender females, but with feminizing medical care most achieve female‑range or lower testosterone concentrations — yet not universally; a nontrivial minority may not suppress fully, and surgical removal of testes typically produces the lowest levels [1] [2] [3] [4]. The cited literature also makes clear that serum testosterone is only one variable in complex physiological outcomes (performance, haemoglobin, muscle), and the sources provided do not settle how hormone history versus present serum levels should be weighted in policy or sport eligibility [6] [5].