Keep Factually independent
Whether you agree or disagree with our analysis, these conversations matter for democracy. We don't take money from political groups - even a $5 donation helps us keep it that way.
Fact check: Are testosterone levels in women the highest during their periods?
Executive Summary
Scientific evidence does not support the claim that testosterone levels in women are highest during menstruation; most studies show peaks around the mid-cycle/ovulatory window or only modest, non-uniform changes across the cycle. Multiple daily- or phase-sampled investigations from 2014–2024 report mid-cycle elevations or small fluctuations, while older and some methodologically limited reports find minimal cyclical variation [1] [2] [3] [4]. The strongest recent data indicate ovulatory-window peaks in testosterone for many women, not menstrual bleeding days [2] [3].
1. Why people believe “periods = high testosterone” and what the evidence actually measures
Lay intuitions connect menstrual bleeding with hormonal extremes, so the claim that testosterone must be highest during periods is understandable, but scientific studies measure circulating total and free testosterone with sensitive assays across cycle phases and often daily sampling. Older studies used intermittently timed blood draws or assays with limited sensitivity, producing mixed results and confusing total versus free fractions [4] [1]. Recent work uses mass-spectrometry or validated immunoassays to capture small amplitude changes and distinguishes free testosterone dynamics; these methods show patterns inconsistent with a consistent menstruation peak [2] [1].
2. What repeated daily-measure studies reveal: a mid-cycle signal, not a menstrual spike
High-resolution, daily-measurement studies find testosterone concentrations tend to rise around mid-cycle—the peri-ovulatory window—rather than at menses. A 2019 study using daily serum sampling and modern assays reported higher concentrations mid-cycle in many participants, though individual variability means a clear peak is not universal across all women [2]. A 2024 salivary testosterone study also documented ovulatory-window peaks, reinforcing the pattern in non-invasive matrices; these findings contradict the statement that menstruation is when testosterone is highest [3].
3. Free versus total testosterone: nuance that changes interpretations
Some reports describe divergent patterns for total testosterone and percent free testosterone across the cycle, which can mislead interpretations about “highest” levels. A 2014 investigation showed total testosterone decreased across the cycle while percent free rose from follicular to luteal phases, and free testosterone fell only at late luteal phase, indicating no clear peak at menstruation [1]. Thus claims about “testosterone highest during periods” often conflate different measures—total, free, or percent free—or ignore the timing of sample collection.
4. Older or small studies that found little cyclic change and why they matter
Several older or lower-resolution studies reported small diurnal or episodic variations but no significant menstrual-cycle fluctuations in free testosterone [4]. These findings remain relevant because they highlight that, at a population level, cyclical changes can be subtle and subject to methodological noise. However, improvements in assay sensitivity and sampling density since those studies have revealed more reproducible mid-cycle patterns in many cohorts, reducing the weight of older null findings when interpreting present-day evidence [2] [3].
5. Clinical outliers: hyperandrogenism and amenorrhea skew patterns
Clinical populations with disorders such as polycystic ovary syndrome or amenorrhea show markedly higher testosterone levels that do not follow normal cyclical patterns, and these results have sometimes been misapplied to healthy cycles. A study noted elevated mean testosterone in hyperandrogenic, amenorrheic women—not that menstruation drives higher testosterone in otherwise cycling women—underscoring how pathology can be conflated with normal physiology [5]. Distinguishing normative cycle dynamics from disease states is essential when answering whether periods coincide with highest testosterone.
6. Reconciling variability: individual differences and measurement timing
Interindividual variability, assay differences, and the choice of matrix (serum vs saliva) create heterogeneity in reported patterns, so blanket statements about “always highest at X phase” are unsupported. Some women may show small rises near menses, others mid-cycle, and a subset will display no clear peak; sampling frequency and assay precision largely determine whether a peak is detected [2] [1]. This methodological reality explains why older literature and some brief-sampling studies appear contradictory when viewed alongside high-resolution recent work.
7. Bottom line for clinicians, researchers, and the public
The preponderance of contemporary, methodologically rigorous evidence indicates that testosterone in normally cycling women is more likely to peak around ovulation than during menstrual bleeding, and claims otherwise usually reflect misinterpretation of older, pathological, or low-resolution studies [2] [3] [1]. For precise individual assessment, clinicians should rely on timed sampling, validated assays, and differentiation of total versus free testosterone, especially when evaluating suspected hyperandrogenism or menstrual irregularities [5] [1].