Free testosterone
Free testosterone is the unbound 2% of testosterone, measured by equilibrium dialysis or calculated. The Endocrine Society states that no harmonized reference range exists. Published lower limits for men run from 64 to 120 pg/mL by method and age. Direct analog immunoassays do not match dialysis. Low calculated levels went with sexual symptoms in men whose total testosterone was normal.
- Status
- A blood test ordered by a clinician and also sold direct to consumers by some US laboratories. A result may be measured by equilibrium dialysis, calculated from total testosterone, sex hormone-binding globulin and albumin, or read from a direct analog immunoassay, which the Endocrine Society calls inaccurate. The same guideline states that no harmonized reference range for free testosterone has been established [1]. FDA classifies testosterone test systems as class I devices [2].
- Measures
- The share of testosterone in blood that is not bound to protein, roughly 2% of the total [3].
- Also called
- free testosterone, free T, FT, testosterone free, calculated free testosterone, cFT, free testosterone calculated, free testosterone by equilibrium dialysis, free testosterone dialysis, free testosterone direct, direct free testosterone, analog free testosterone
- Tested for
- low testosterone with a normal total testosterone, low sex drive, erectile dysfunction, fatigue, effects of high or low SHBG, obesity, aging, excess hair growth in women
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Linked in research1
Reported risks0
No risks sourced yet.
Reference ranges
Each range is the one its source published, in pg/mL. Also reported in pmol/L. Where sources differ, each is shown.
Jasuja and colleagues, 2023, equilibrium dialysis, men aged 19 and older
Men aged 19 and older, measured by a standardized equilibrium dialysis procedure · [4]
| Range | What the source calls it |
|---|---|
| below 66 pg/mL | No name given |
| 66 to 309 pg/mL | "normative range" |
| above 309 pg/mL | No name given |
The 2.5th and 97.5th percentiles in 145 men whom the study classed as healthy and nonobese, printed as 66 to 309 pg/mL (229 to 1072 pmol/L). Dialysis ran for 16 hours at 37 degrees C on undiluted serum, and free testosterone in the dialysate was measured by a mass spectrometry assay certified by the Centers for Disease Control and Prevention. The authors state that dialysis methods and reference intervals vary among laboratories, and that these intervals need validation in other populations and against outcomes [4].
Jasuja and colleagues, 2023, equilibrium dialysis, men aged 19 to 39
Men aged 19 to 39, measured by a standardized equilibrium dialysis procedure · [4]
| Range | What the source calls it |
|---|---|
| below 120 pg/mL | No name given |
| 120 to 368 pg/mL | "normative range" |
| above 368 pg/mL | No name given |
The 2.5th and 97.5th percentiles in the men aged 19 to 39 within the same 145-man sample, printed as 120 to 368 pg/mL (415 to 1274 pmol/L). The abstract does not give the number of men in this age group. Levels declined across age groups [4].
Framingham Heart Study reference sample, 2011, calculated
Men, from a reference sample aged 19 to 40, calculated free testosterone · [5]
| Range | What the source calls it |
|---|---|
| below 70 pg/mL | "low" |
| 70 or above pg/mL | "normal" |
The 2.5th percentile of calculated free testosterone in 456 men aged 19 to 40 whom the study classed as healthy and nonobese, with total testosterone measured by liquid chromatography tandem mass spectrometry. The mean was 141.8 pg/mL. The abstract prints no upper limit and does not name the equation [5].
European Male Aging Study criteria, 2010, calculated
Men aged 40 to 79 who have at least three sexual symptoms, calculated free testosterone · [6]
| Range | What the source calls it |
|---|---|
| below 64 pg/mL | No name given |
| 64 or above pg/mL | No name given |
Printed as 220 pmol/L (64 pg/mL) and calculated with Vermeulen's formula. The cohort's criteria for late-onset hypogonadism are at least three sexual symptoms together with total testosterone below 11 nmol/L and free testosterone below this figure. The chance of the three sexual symptoms and of limited physical vigor rose as free testosterone fell through 160 to 280 pmol/L (46 to 81 pg/mL). Derived from 3,369 men at eight European centers [6].
European Association of Urology guideline, 2026
Men with conditions that alter sex hormone-binding globulin, calculated free testosterone · [7]
| Range | What the source calls it |
|---|---|
| below 64 pg/mL | No name given |
| 64 or above pg/mL | No name given |
Printed as 220 pmol/L (6.4 ng/dL), which is 64 pg/mL. The guideline states that limited evidence indicates this can be considered a reliable threshold. It calls equilibrium dialysis the most accurate method, accepts calculation from sex hormone-binding globulin and albumin, and states that available immunoassays do not give an accurate estimate [7].
International Society of Andrology, ISSAM, EAU, EAA and ASA recommendations, 2008
Men assessed for late-onset hypogonadism whose total testosterone is not diagnostic · [8]
| Range | What the source calls it |
|---|---|
| below 65 pg/mL | No name given |
| 65 or above pg/mL | No name given |
Printed as 225 pmol/L (65 pg/mL). The five societies state that there are no generally accepted lower limits of normal for free testosterone, and offer this figure as supporting evidence in men whose total testosterone is not diagnostic. They name equilibrium dialysis as the gold standard and state that analog displacement immunoassays do not give an accurate measurement [8]. The British Society for Sexual Medicine keeps the same 225 pmol/L figure in its 2023 guideline [9].
American Board of Internal Medicine laboratory reference ranges, 2026, men
Men, as a general laboratory reference range · [10]
| Range | What the source calls it |
|---|---|
| below 70 pg/mL | No name given |
| 70 to 300 pg/mL | "reference range" |
| above 300 pg/mL | No name given |
The table names no method, assay or age group, and gives no free testosterone range for women [10].
Braunstein and colleagues, 2011, premenopausal women, measured
Premenopausal women with regular menstrual cycles, estimated for age 30 · [11]
| Range | What the source calls it |
|---|---|
| below 1.2 pg/mL | No name given |
| 1.2 to 6.4 pg/mL | "reference range" |
| above 6.4 pg/mL | No name given |
The estimated 5th and 95th percentiles for a 30-year-old woman, printed as 1.2 to 6.4 pg/mL (4.16 to 22.2 pmol/L), from 161 women aged 18 to 49 sampled in the morning at three points in the menstrual cycle. The abstract does not name the method used for the measured value. The authors included employees of a commercial laboratory and of two companies [11].
Braunstein and colleagues, 2011, premenopausal women, calculated
Premenopausal women with regular menstrual cycles, estimated for age 30, calculated free testosterone · [11]
| Range | What the source calls it |
|---|---|
| below 1.3 pg/mL | No name given |
| 1.3 to 5.6 pg/mL | "reference range" |
| above 5.6 pg/mL | No name given |
The estimated 5th and 95th percentiles of calculated free testosterone for a 30-year-old woman, printed as 1.3 to 5.6 pg/mL (4.5 to 19.4 pmol/L), from the same 161 women [11].
What has been shown to move it
Shown to lower it4
Lower testosterone and higher SHBG
Shown to lower total testosterone and cut free testosterone by about 61% in healthy women on combined pills, while SHBG rose about 99 nmol/L.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Total testosterone fell (MD -0.49 nmol/L, 95% CI -0.55 to -0.42), free testosterone fell 61% (relative level 0.39), and SHBG rose (MD 99.08 nmol/L, 95% CI 86.43 to 111.73). Ethinyl estradiol dose and progestin type did not change the testosterone fall, but pills with second-generation progestins or 20 to 25 µg ethinyl estradiol raised SHBG less [7].
- Population
- 1,495 healthy women aged 18 to 40 in 42 studies [7].
- Sources
- [7]
- Caveats
- Half the studies were non-comparative. The clinical effects of lower androgens remain unclear [7].
Hormones and blood sugar in PCOS
Shown to lower free and total testosterone and glucose and raise SHBG in women with PCOS. Metformin did better on hirsutism.
The numbers and sources
- Effect
- Against placebo, inositol lowered BMI (MD -0.45), free testosterone (MD -0.41), total testosterone (MD -20.4) and glucose (MD -3.14), and raised sex-hormone-binding globulin (MD 32.1) [1]. The guideline review found benefits for some metabolic measures and none for others. Metformin did better on waist-hip ratio and hirsutism [3].
- Population
- 1,691 women in 26 trials [1]; 2,230 women in 30 trials [3].
- Sources
- [1], [3]
- Caveats
- Units are as reported in the abstract. The guideline review rated BMI evidence very uncertain [3].
Reproductive hormones and cycles in PCOS
Shown in pooled studies, mostly before and after the diet, to lower LH and testosterone and raise SHBG in women with PCOS. Against other diets, androgen results were inconsistent.
Compared with before the diet, in the same women [25][23][21][22]; other diets [21]; low-calorie diets [22]
The numbers and sources
- Effect
- After 45 days or more on a ketogenic diet, the LH to FSH ratio fell (d -0.851, 95% CI -1.015 to -0.686), free testosterone fell (d -0.223, 95% CI -0.328 to -0.119) and SHBG rose (d 9.086, 95% CI 3.379 to 14.792) [25]. A second review found lower LH, LH to FSH ratio, free and total testosterone and higher SHBG and FSH after the diet [23]. Menstrual cycle length shortened and LH fell from before to after the diet, while androgen results against other diets were inconsistent [21]. In 2 RCTs, LH was lower than on low-calorie diets [22].
- Population
- Women with PCOS in single- or double-arm clinical trials [25]; 7 studies [23]; 15 studies, 10 pooled [21]; 10 studies including 3 RCTs [22].
- Sources
- [25], [23], [21], [22]
- Caveats
- Diets lasted weeks to months, and all reviews were limited by small, mostly uncontrolled studies. Pregnancy and live birth data were too scarce to pool [23].
Lower testosterone and HDL cholesterol
Shown to lower testosterone and HDL cholesterol in healthy men, more at higher doses. Levels returned to baseline after stopping.
FSH and free testosterone fell at the highest dose.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- LGD-4033 lowered total testosterone, sex hormone-binding globulin, HDL cholesterol and triglycerides in a dose-dependent way. FSH and free testosterone fell at the highest dose. Levels returned to baseline after stopping [1]. The 2026 review reports suppression of testosterone, sex hormone-binding globulin and HDL cholesterol across randomized trials, with reversible rises in liver enzymes for some compounds [4].
- Population
- 76 healthy young men over 21 days and 5 weeks of follow-up [1]; trials summarized in a review [4].
- Sources
- [1], [4]
- Caveats
- Trial doses were lower and shorter than the stacked, unmonitored use the review describes [4].
Shown to raise it1
Testosterone in men: clomiphene
Shown to raise total testosterone in men with low testosterone, by about 274 ng/dL against placebo, in pooled trials of clomiphene or enclomiphene.
Compared with placebo [13]; testosterone gel [13]; human chorionic gonadotropin [13]; the same men before treatment [14]
Across 17 studies pooled in a second review, total testosterone rose during treatment (pooled estimate 2.60, 95% CI 1.82 to 3.38, unit not given in the abstract), along with free testosterone, LH, FSH, SHBG and estradiol.
The numbers and sources
- Effect
- Against placebo, clomiphene or enclomiphene raised total testosterone by 273.76 ng/dL (95% CI 191.87 to 355.66, I² 89%), LH by 4.66 IU/L and FSH by 4.59 IU/L. Total testosterone did not differ from testosterone gel. Levels were higher than with hCG alone [13]. Across 17 studies pooled in a second review, total testosterone rose during treatment (pooled estimate 2.60, 95% CI 1.82 to 3.38, unit not given in the abstract), along with free testosterone, LH, FSH, SHBG and estradiol. Symptom scores on the Androgen Deficiency in Aging Males questionnaire improved. Side effects were reported by fewer than 10% of study populations and no serious adverse events were reported [14].
- Population
- Men with functional hypogonadism in randomized trials [13]. 1,642 men with hypogonadism in 19 studies, 4 randomized and 15 observational, treated for 1.5 to 52 months [14].
- Sources
- [13], [14]
- Caveats
- The first review pooled clomiphene with enclomiphene and heterogeneity was high [13]. The second rests mostly on before-and-after observational studies [14]. Use in men is off-label in the US [1]. Neither abstract reports fractures, heart events or fertility.
Studies disagree2
Testosterone
Mixed results: one 12-day trial found testosterone up 42% from baseline in untrained men, while trials in trained men found no rise or a fall at 6 g.
In resistance-trained men, 3 g a day for 28 days did not change total or free testosterone, LH or estradiol.
The numbers and sources
- Effect
- In 23 men aged 27 to 37 given 3.12 g of sodium D-aspartate a day for 12 days, testosterone rose from 4.5 to 6.4 ng/mL, a 42% increase over baseline, and LH rose 33%. Twenty men on placebo did not change [1]. In resistance-trained men, 3 g a day for 28 days did not change total or free testosterone, LH or estradiol [2]. In 24 trained men over 14 days, 3 g a day had no effect, and 6 g a day lowered total and free testosterone [3]. In 22 trained men over 12 weeks, 6 g a day did not change total or free testosterone [4]. In 16 boxers at simulated altitude, 6 g a day for 14 days did not change resting testosterone or LH [5]. A systematic review of 4 human studies found the results inconsistent and the studies few and of poor quality [6].
- Population
- Healthy men in Italy [1]; resistance-trained men [2][3][4]; male boxers [5].
- Sources
- [1], [2], [3], [4], [5], [6]
- Caveats
- The rise in [1] was reported against the same men's baseline, and the product was a commercial preparation also containing vitamins B6, B12 and folic acid. All trials were small and lasted 2 to 12 weeks.
Lower testosterone at 6 g a day
One small trial found 6 g a day for 14 days lowered total and free testosterone in 24 trained men. A 12-week trial found no change.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- In trained men, 6 g a day for 14 days lowered total testosterone (p = 0.03), and free testosterone was lower than with the flour placebo (p = 0.005). Estradiol, SHBG and albumin did not change [3].
- Population
- 24 resistance-trained men [3].
- Sources
- [3]
- Caveats
- The 12-week trial at the same dose found no change in testosterone [4].
Tested, and not shown to change it3
Testosterone and estrogen in men
Not shown to change total or free testosterone, estrogen or SHBG in men eating soy foods, soy protein or isoflavones, in two pooled analyses of clinical studies.
Compared with placebo groups [15]; values before intake in the same men, in simpler models [15]; control and baseline values the abstract does not detail [14]
The numbers and sources
- Effect
- Across 41 studies, soy protein or isoflavone intake had no significant effect on total testosterone, free testosterone, estradiol, estrone or SHBG, regardless of the statistical model, dose or study duration [14]. An earlier analysis of 15 placebo-controlled treatment groups, and 36 groups in simpler models, found no effect on testosterone, SHBG, free testosterone or free androgen index [15].
- Population
- Total testosterone measured in 1,753 men, free testosterone in 752 and estradiol in 1,000 [14]. Adult men in 32 reports [15].
- Sources
- [14], [15]
- Caveats
- Several authors of both analyses overlap. Studies included isoflavone extracts from soy or red clover as well as soy foods [14][15].
Total testosterone
Shown to raise total testosterone in men, including men with low testosterone, in few small trials, one run partly by the maker.
In 105 men aged 50 to 70 with testosterone below 300 ng/dL, 200 mg a day raised total testosterone over placebo at weeks 4, 8 and 12, and free testosterone did not differ between groups.
The numbers and sources
- Effect
- Across 5 RCTs, tongkat ali raised total testosterone (SMD 1.352, 95% CI 0.565 to 2.138), with the effect confirmed in the hypogonadism subgroup [1]. In 105 men aged 50 to 70 with testosterone below 300 ng/dL, 200 mg a day raised total testosterone over placebo at weeks 4, 8 and 12, and free testosterone did not differ between groups [2].
- Population
- Healthy and hypogonadal men in 9 studies reviewed and 5 pooled [1]; ageing men in India for 12 weeks [2].
- Sources
- [1], [2]
- Caveats
- Few small trials. Two authors of [2], including the first author, were at Biotropics Malaysia Berhad, maker of the Physta extract it tested.
Testosterone
Limited evidence: total testosterone rose by a small amount in men, free testosterone did not change, and certainty was very low.
The numbers and sources
- Effect
- Across 6 placebo-controlled trials, fenugreek preparations raised total testosterone by a small amount (SMD 0.25, 95% CI 0.02 to 0.48, I² 0%), while free testosterone did not change (SMD 0.08, 95% CI -0.48 to 0.63). None of 13 studies was rated low risk of bias, and certainty was very low. The authors state the evidence does not support testosterone-boosting claims [4]. An earlier meta-analysis of 4 trials reported a significant effect on total testosterone without stating its size in the abstract [5]. In 95 men aged 40 to 80, 12 weeks of an extract did not raise plasma testosterone over placebo (9.0%, p = 0.122) but raised salivary testosterone (37.2%, p = 0.042) [6].
- Population
- Adult men [4][5]; 95 men aged 40 to 80 who completed a 12-week trial [6].
- Sources
- [4], [5], [6]
- Caveats
- The trial in [6] was funded in part by Vitas Ltd and PurOmega Ltd, and its product also contained essential nutrients.
How it compares with the reference method
Mixed results3
Calculated free testosterone
Mixed results: calculated values tracked dialysis closely in two comparisons, while a study of 2,159 samples found common formulas overestimated it.
The numbers and sources
- Compared with
- Equilibrium dialysis
- Effect
- Free testosterone calculated from total testosterone and sex hormone-binding globulin was almost identical to the dialysis value under all conditions studied except pregnancy [17]. In 147 women, calculated values correlated with dialysis at r = 0.99, and the agreement depended strongly on the assays used for total testosterone and the binding globulin [14]. In 2,159 serum samples from men at one research laboratory, commonly used formulas significantly overestimated free testosterone against dialysis, while two newer empirical formulas were more concordant, and correcting for albumin, obesity, ethnicity or gonadal status did not change accuracy [19]. The Endocrine Society states that estimates from an allosteric model closely approximate dialysis values [1].
- Population
- Sera with varied binding globulin levels [17]. 147 women [14]. 2,159 samples from men [19].
- Sources
- [17], [14], [19], [1]
- Caveats
- A calculated value inherits the error of the total testosterone and binding globulin assays behind it [14]. The first comparison was run by the group whose formula it tested [17].
Variation after glucose and from one test to the next
Limited evidence: free testosterone fell after a glucose drink in one study, and repeat hormone results in one man often differed by a fifth or more.
The numbers and sources
- Compared with
- The same man's fasting or earlier sample
- Effect
- In 74 men given a 75 g oral glucose load, total and calculated free testosterone both fell significantly, with total testosterone down 25% [20]. In 132 men sampled up to six times over 6 months, within-person variation across eleven hormone measures, free testosterone among them, implied that two results would differ by more than 18 to 28% about half the time, depending on the hormone [21].
- Population
- 74 men aged 19 to 74 [20]. 132 men aged 30 to 79 in Boston [21].
- Sources
- [20], [21]
- Caveats
- Neither abstract gives the size of the change for free testosterone alone [20][21].
Diagnosing raised androgens in polycystic ovary syndrome
Shown in three meta-analyses to pick out women with PCOS with 76% to 89% sensitivity and 82% to 85% specificity, as calculated free testosterone or the free androgen index.
The numbers and sources
- Compared with
- PCOS diagnosed by the Rotterdam, NIH or Androgen Excess and PCOS Society criteria, against women without PCOS
- Effect
- In one meta-analysis, calculated free testosterone had a pooled sensitivity of 0.89 (95% CI 0.69 to 0.96), specificity of 0.83 (0.79 to 0.86) and area under the curve of 0.85 (0.81 to 0.88). The free androgen index had 0.78, 0.85 and 0.87. Mass spectrometry gave better sensitivity than direct immunoassay for both, and better specificity [22]. Two meta-analyses of the free androgen index alone found a sensitivity of 0.76 and specificity of 0.82, area under the curve 0.84, in 7 studies [23], and 0.81 and 0.82, area under the curve 0.88, in 14 studies whose cut-offs varied [24]. The 2023 international PCOS guideline names free testosterone, assessed by calculation, equilibrium dialysis or ammonium sulfate precipitation, or estimated with the free androgen index, as a first test alongside total testosterone [25].
- Population
- 2,857 participants, 1,650 with PCOS, in 18 studies [22]. 7 studies [23]. 2,870 women with PCOS and 3,985 without, in 14 studies [24].
- Sources
- [22], [23], [24], [25]
- Caveats
- The free androgen index is calculated from total testosterone and SHBG, so it shifts with SHBG, which changes with age, weight and medication [22]. Raised androgens are one of the criteria that define PCOS, so the test is partly measured against a diagnosis it helps make. The guideline notes that the combined pill raises SHBG, which makes testing in women taking it unreliable [25].
Did not match the reference method1
Direct analog immunoassay
Shown not to match equilibrium dialysis: direct analog immunoassays read a fraction of the dialysis value and followed total testosterone, not free testosterone.
The numbers and sources
- Compared with
- Equilibrium dialysis
- Effect
- Across sera with widely varying sex hormone-binding globulin, analog immunoassay values were only a fraction of the free testosterone found by dialysis, and the fraction changed with the binding globulin level [17]. In laboratory experiments, an analog assay did not detect the free testosterone in dialysate, and its results followed total testosterone and did not follow free testosterone when total testosterone was held constant [18]. In 147 women, direct radioimmunoassay had high systematic bias and random variability and correlated less closely with dialysis (r = 0.81) than calculated values did (r = 0.99) [14]. The Endocrine Society, the European Association of Urology and a joint statement of five societies each state that these assays are inaccurate [1][7][8].
- Population
- Sera from men and women with low to very high binding globulin levels [17]. Serum fractions from normal male serum [18]. 147 women with varied androgen and estrogen status, each sampled three times in a month [14].
- Sources
- [17], [18], [14], [1], [7], [8]
- Caveats
- A laboratory report does not always say which method produced a free testosterone result. The American Urological Association describes the direct method differently, as correlating with dialysis and being unreliable because of high variation [3].
What studies tie it to
Linked in research1
Symptoms, physical function and diabetes in men
Linked to sexual symptoms, slower walking and diabetes in men with low calculated free testosterone, including men whose total testosterone was in range.
The numbers and sources
- Effect
- In 3,334 European men aged 40 to 79, the 277 with normal total testosterone and calculated free testosterone below 220 pmol/L were older and in poorer health and reported more sexual and physical symptoms than men with both in range, with lower hemoglobin and bone ultrasound values. The 96 men with low total testosterone and normal free testosterone were younger and more obese and lacked features of androgen deficiency [12]. In three cohorts, men below the 2.5th percentile of a young reference sample for total and free testosterone were more likely to have slow walking speed, difficulty climbing stairs or frailty, and diabetes, than men with normal levels [5]. In the European cohort, the chance of three sexual symptoms rose as free testosterone fell through 160 to 280 pmol/L (46 to 81 pg/mL) [6].
- Population
- 3,334 community-dwelling men aged 40 to 79 in the European Male Aging Study [12]. Men in the Framingham Heart Study, the European Male Aging Study and the Osteoporotic Fractures in Men Study [5]. 3,369 men aged 40 to 79 [6].
- Sources
- [12], [5], [6]
- Caveats
- Cross-sectional, so these studies cannot show which came first. Free testosterone was calculated, not measured, in all three. Two of the three analyses use the same European cohort.
Mixed results1
Outcomes in trials that raised testosterone
Limited evidence: the large testosterone treatment trials enrolled men by total testosterone, so they do not show what correcting a low free testosterone alone does.
The numbers and sources
- Effect
- A trial of 790 men aged 65 or older enrolled on a total testosterone below 275 ng/dL and found improved sexual function with no benefit for vitality or walking distance [15]. A trial of 5,246 men enrolled on two fasting total testosterone levels below 300 ng/dL and found no difference in major cardiac events (hazard ratio 0.96, 95% CI 0.78 to 1.17) [16]. The American Urological Association states that total and free testosterone are not interchangeable and that no clear data point to consistent thresholds between the two below which symptoms appear and above which treatment benefits occur [3].
- Population
- 790 men treated for 1 year [15]. 5,246 men aged 45 to 80, mean follow-up 33.0 months [16].
- Sources
- [15], [16], [3]
- Caveats
- A marker that tracks an outcome is not always one whose correction changes it. Neither trial reports results by free testosterone level in its abstract.
Checked, no link found1
Sexual function in women
One survey found no link between a low free testosterone and low self-reported sexual function in women aged 18 to 75.
The numbers and sources
- Effect
- In a community survey, no clinically significant relationship was found between a low score in any domain of sexual function and a low serum total or free testosterone. A low dehydroepiandrosterone sulfate level did go with low scores in some domains, and the authors concluded that no single androgen level predicts low sexual function in women [13].
- Population
- 1,021 women drawn at random from the electoral roll in Victoria, Australia [13].
- Sources
- [13]
- Caveats
- One cross-sectional survey from 2002 and 2003. A comparison of methods in women found the direct immunoassay had high bias and a higher detection limit than dialysis [14].
Sources
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology and Metabolism. 2018. https://doi.org/10.1210/jc.2018-00229
- US Food and Drug Administration. 21 CFR 862.1680, Testosterone test system. Electronic Code of Federal Regulations. https://www.ecfr.gov/current/title-21/section-862.1680
- Mulhall JP, Trost LW, Brannigan RE, et al. Evaluation and Management of Testosterone Deficiency: AUA Guideline. Journal of Urology. 2018. https://doi.org/10.1016/j.juro.2018.03.115
- Jasuja R, Pencina KM, Spencer DJ, et al. Reference intervals for free testosterone in adult men measured using a standardized equilibrium dialysis procedure. Andrology. 2023. https://doi.org/10.1111/andr.13310
- Bhasin S, Pencina M, Jasuja GK, et al. Reference Ranges for Testosterone in Men Generated Using Liquid Chromatography Tandem Mass Spectrometry in a Community-Based Sample of Healthy Nonobese Young Men in the Framingham Heart Study and Applied to Three Geographically Distinct Cohorts. The Journal of Clinical Endocrinology and Metabolism. 2011. https://doi.org/10.1210/jc.2010-3012
- Wu FCW, Tajar A, Beynon JM, et al. Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men. New England Journal of Medicine. 2010. https://doi.org/10.1056/nejmoa0911101
- European Association of Urology. EAU Guidelines on Sexual and Reproductive Health, chapter 3, Male Hypogonadism. 2026 edition. https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-hypogonadism
- Wang C, Nieschlag E, Swerdloff R, et al. Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations. European Journal of Endocrinology. 2008. https://doi.org/10.1530/eje-08-0601
- Hackett G, Kirby M, Rees RW, et al. The British Society for Sexual Medicine Guidelines on Male Adult Testosterone Deficiency, with Statements for Practice. The World Journal of Men's Health. 2023. https://doi.org/10.5534/wjmh.221027
- American Board of Internal Medicine. ABIM Laboratory Test Reference Ranges. January 2026. https://www.abim.org/Media/bfijryql/laboratory-reference-ranges.pdf
- Braunstein GD, Reitz RE, Buch A, et al. Testosterone Reference Ranges in Normally Cycling Healthy Premenopausal Women. The Journal of Sexual Medicine. 2011. https://doi.org/10.1111/j.1743-6109.2011.02380.x
- Antonio L, Wu FCW, O'Neill TW, et al. Low Free Testosterone Is Associated with Hypogonadal Signs and Symptoms in Men with Normal Total Testosterone. The Journal of Clinical Endocrinology and Metabolism. 2016. https://doi.org/10.1210/jc.2015-4106
- Davis SR, Davison SL, Donath S, Bell RJ. Circulating Androgen Levels and Self-reported Sexual Function in Women. JAMA. 2005. https://doi.org/10.1001/jama.294.1.91
- Miller KK, Rosner W, Lee H, et al. Measurement of Free Testosterone in Normal Women and Women with Androgen Deficiency: Comparison of Methods. The Journal of Clinical Endocrinology and Metabolism. 2004. https://doi.org/10.1210/jc.2003-030680
- Snyder PJ, Bhasin S, Cunningham GR, et al. Effects of Testosterone Treatment in Older Men. New England Journal of Medicine. 2016. https://doi.org/10.1056/nejmoa1506119
- Lincoff AM, Bhasin S, Flevaris P, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. New England Journal of Medicine. 2023. https://doi.org/10.1056/nejmoa2215025
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