Testosterone levels change throughout life. While testosterone is often discussed in the context of men's health, it is an important hormone in both men and women, and normal levels differ significantly by sex, age, reproductive stage, laboratory method, and individual physiology.
That is why a simple testosterone levels by age chart can sometimes create more confusion than clarity.
There is no single testosterone number that everyone of a certain age should have. Population averages can help show how testosterone changes over time, but an average is not necessarily an ideal level, a diagnostic cutoff, or a treatment target.
For example, research using standardized testosterone measurements established a reference range of approximately 264 to 916 ng/dL for healthy, nonobese men ages 19 to 39. Women naturally have substantially lower testosterone concentrations, and research also shows that female testosterone levels tend to decline across adulthood.
Understanding your testosterone level therefore requires more than comparing one laboratory result with an online chart.
This guide explains testosterone levels by age, average and healthy ranges, total versus free testosterone, testosterone levels in men and women, common measurement units, and what low or high results may mean.
Quick answer: Testosterone levels generally change with age in both men and women, but there is no universal "healthy testosterone level" for every decade of life. Men typically have much higher circulating testosterone than women. Testosterone interpretation should consider age, sex, symptoms, laboratory reference ranges, testing method, time of collection, SHBG, medications, and reproductive status.
What Is Testosterone?
Testosterone is an androgen, a class of steroid hormones involved in sexual development, reproductive function, bone health, muscle physiology, and numerous other processes throughout the body.
In men, most testosterone is produced by the testes under regulation from the hypothalamus and pituitary gland.
Women also naturally produce testosterone. Testosterone and its androgen precursors come from the ovaries, adrenal glands, and peripheral conversion of other hormones.
Testosterone plays roles in
sexual development
libido and sexual function
reproductive physiology
muscle and bone health
red blood cell production
body composition
hair growth
numerous metabolic and physiological processes
The amount of testosterone circulating in the blood differs substantially between men and women, which is why testosterone results must be interpreted in the appropriate clinical context.
What Are Normal Testosterone Levels by Age?
There is no universal normal testosterone number assigned to each age.
This distinction is important when looking for healthy testosterone levels by age.
A laboratory reference range represents values observed in a particular reference population using a particular testing method. It does not necessarily represent the ideal testosterone level for every person.
One major harmonization study involving more than 9,000 community-dwelling men from several U.S. and European cohorts established a standardized total testosterone reference range of approximately 264 to 916 ng/dL for healthy, nonobese men ages 19 to 39.
Women's testosterone concentrations are substantially lower.
Research using liquid chromatography-tandem mass spectrometry, or LC-MS/MS, in women ages 20 to 80 found an overall total testosterone reference interval of approximately 0.35 to 1.97 nmol/L, while also demonstrating that testosterone declined significantly with age.
These ranges are useful for understanding population patterns, but they should not replace the reference interval provided by the laboratory performing an individual's test.
Testosterone Levels by Age
Testosterone changes considerably from childhood through older adulthood.
Rather than thinking of each decade as having one correct testosterone number, it is more useful to understand the overall pattern.
Childhood
Testosterone concentrations are generally low before puberty in both males and females.
Puberty
Testosterone rises substantially during male puberty and contributes to changes such as development of secondary sexual characteristics.
Testosterone and other androgens also increase during female puberty, although circulating testosterone remains much lower than in males.
Late Teens and 20s
Testosterone is generally among its higher adult levels during younger adulthood, particularly in men.
Women also generally have higher androgen concentrations during younger adulthood than later in life.
30s
Population testosterone levels may begin showing gradual age-related changes, although there is considerable individual variation.
A healthy person in their 30s can have a testosterone concentration substantially different from another healthy person of the same age.
40s
Age-related differences become more apparent at the population level.
For women, reproductive changes and the transition toward menopause can also become increasingly relevant when interpreting hormone results.
50s
Men, on average, tend to have lower testosterone concentrations than during younger adulthood, although many remain within laboratory reference ranges.
For women, menopause, ovarian aging, medications, and hormone therapy can become particularly important considerations.
60s and Older
Average testosterone concentrations tend to be lower than during younger adulthood.
However, there remains considerable person-to-person variation.
An older person's testosterone should therefore not automatically be considered abnormal simply because it is lower than the average testosterone level of someone in their 20s.
Testosterone Levels in Men by Age
Testosterone levels in men rise dramatically during puberty, remain relatively high through early adulthood, and generally decline with increasing age.
But age is only one factor affecting testosterone.
Body composition, chronic illness, medications, sleep, pituitary function, testicular function, and other health factors can also influence testosterone concentrations.
A large harmonized analysis established the following reference interval for healthy, nonobese men ages 19 to 39
Total testosterone: approximately 264 to 916 ng/dL
The median was approximately 531 ng/dL.
The 5th percentile was approximately 303 ng/dL, while the 95th percentile was approximately 852 ng/dL.
These numbers should not be interpreted as treatment targets.
A man with testosterone below 531 ng/dL does not automatically have low testosterone simply because he is below the median.
Likewise, being above the population average does not necessarily mean someone has better hormonal health.
Average Testosterone Levels by Age Are Not Treatment Targets
One of the biggest problems with many testosterone level charts online is that they blur three different concepts:
Average testosterone
This describes the central tendency of testosterone measurements in a studied population.
Testosterone reference range
This describes the statistical range observed in a defined reference population.
Diagnostic threshold
This is a clinical value that may help determine whether someone meets criteria for a medical condition when considered alongside symptoms and other findings.
These numbers answer different questions.
If a study finds that the average testosterone level among a certain age group is 500 ng/dL, that does not mean everyone in that age group should have testosterone of 500 ng/dL.
It also does not mean someone at 450 ng/dL needs testosterone treatment.
What Testosterone Level Is Considered Low in Men?
For adult men, the American Urological Association recommends using a total testosterone level below 300 ng/dL as a reasonable cutoff supporting the diagnosis of testosterone deficiency.
But that number should not be interpreted in isolation.
The AUA recommends diagnosing testosterone deficiency only after testosterone is measured on two separate occasions, with both measurements performed in the early morning. Diagnosis also requires low testosterone in combination with relevant symptoms and/or signs.
The Endocrine Society similarly recommends diagnosing hypogonadism only in men who have symptoms or signs consistent with testosterone deficiency and unequivocally and consistently low testosterone concentrations. It recommends confirming the finding with repeat morning testing.
In other words
Symptoms alone do not diagnose low testosterone.
And
One low testosterone result generally does not diagnose hypogonadism.
The Endocrine Society reiterated in 2026 that the diagnostic approach applies regardless of age and emphasized the importance of distinguishing normal aging from clinically diagnosed hypogonadism.
Testosterone Levels in Women by Age
Women naturally have much lower circulating testosterone concentrations than men, but testosterone remains an important component of female endocrine physiology.
Women's testosterone levels also change with age.
A study of 985 women ages 20 to 80 using LC-MS/MS found significant age-related declines in total testosterone, free testosterone, and androstenedione.
Across the overall study population, total testosterone was approximately 0.35 to 1.97 nmol/L, while calculated free testosterone was approximately 0.0025 to 0.0253 nmol/L.
Importantly, those researchers developed age-related reference ranges rather than assuming one testosterone range was equally appropriate throughout adulthood.
Another study examining healthy, normally cycling premenopausal women ages 18 to 49 also found an age-related decrease in testosterone.
For a typical 30-year-old woman, the estimated 5th to 95th percentile values were approximately
Total testosterone: 15 to 46 ng/dL
Free testosterone: 1.2 to 6.4 pg/mL
These values describe specific study populations and testing methods. They should not replace the reference interval supplied by the laboratory performing an individual's test.
Testosterone Levels by Age in Women
Female testosterone levels do not remain constant throughout adulthood.
During puberty, testosterone and other androgens increase as part of normal development.
During the 20s and early reproductive years, testosterone concentrations are generally higher than during later adulthood.
Levels tend to decline gradually through the 30s and 40s, although the rate of change differs substantially between individuals.
During perimenopause and menopause, interpretation becomes more complex because ovarian aging occurs alongside changes in estrogen, progesterone, SHBG, and other hormones.
During older adulthood, average androgen concentrations are generally lower than during younger reproductive years.
This pattern should not be interpreted as meaning every older woman has "testosterone deficiency."
Women's hormone health cannot be determined from age and testosterone concentration alone.
Does Testosterone Drop During Menopause?
Women's testosterone levels generally decline across adulthood, but the relationship between testosterone and menopause is more complicated than simply saying testosterone suddenly falls when menopause begins.
Age, ovarian function, adrenal androgen production, reproductive status, medications, and hormone therapy can all influence measured testosterone.
Research examining women across adulthood has demonstrated a significant age-related decline in total and free testosterone.
However, a low testosterone result in a woman should not automatically be interpreted as a disease requiring testosterone therapy.
The Endocrine Society has recommended against diagnosing a generalized androgen deficiency syndrome in healthy women, noting that a clearly defined syndrome and a consistent relationship between androgen levels and specific symptoms have not been established.
This is why women's testosterone treatment requires a different clinical framework from male TRT.
What Are Healthy Testosterone Levels by Age?
There is no single "optimal" testosterone level for every age.
A healthy testosterone result should be interpreted using the individual's overall clinical picture.
Important factors can include
age
sex
symptoms
total testosterone
free testosterone when appropriate
SHBG
time of blood collection
laboratory methodology
medications
body composition
reproductive status
menstrual or menopausal status
pituitary and gonadal function
underlying health conditions
A person can fall within a laboratory reference range and still have symptoms requiring medical investigation.
Conversely, a borderline or slightly abnormal testosterone result does not automatically mean hormone treatment is necessary.
Total Testosterone vs. Free Testosterone
Understanding the difference between total testosterone and free testosterone is important when interpreting testosterone levels by age.
Total Testosterone
Total testosterone measures testosterone circulating in the blood in multiple forms, including testosterone bound to proteins and the small amount circulating freely.
Total testosterone is commonly reported in
ng/dL
nmol/L
Free Testosterone
Free testosterone can provide additional insight into hormonal health, particularly when total testosterone results do not fully explain a person's symptoms. Sex hormone-binding globulin (SHBG) can influence how much testosterone remains unbound, making both measurements important in certain clinical evaluations. To understand why free testosterone matters and how it differs from total testosterone, read our guide: Free Testosterone: Why Measuring the Active Hormone Matters More Than Total Testosterone.
Free testosterone refers to the small fraction of testosterone that is not bound to circulating proteins.
Depending on the laboratory and method, free testosterone may be reported in:
pg/mL
ng/dL
pmol/L
Because the measurements and units are different, a total testosterone result should never be directly compared with a free testosterone reference range.
Free Testosterone Levels by Age
Free testosterone also changes with age.
A standardized study using equilibrium dialysis in healthy, nonobese adult men established a free testosterone reference interval of approximately 66 to 309 pg/mL across its overall adult study population.
Among men ages 19 to 39, the reference interval was approximately 120 to 368 pg/mL.
The researchers also found that free testosterone decreased with age and was associated with BMI and SHBG.
Women naturally have much lower free testosterone concentrations.
In the premenopausal study discussed earlier, the estimated free testosterone interval for a typical 30-year-old woman was approximately 1.2 to 6.4 pg/mL.
Free testosterone values require particularly careful interpretation because results can vary depending on how free testosterone is measured or calculated.
For this reason, an online free testosterone levels pg/mL by age chart should not override the laboratory's validated method and reference interval.
What Is SHBG and Why Does It Matter?
SHBG stands for sex hormone-binding globulin.
It is a protein that binds sex hormones, including testosterone.
Changes in SHBG can affect the relationship between total and free testosterone.
This means two people can have the same total testosterone concentration while having different amounts of free testosterone.
SHBG can itself be influenced by physiological conditions, medications, hormone status, and other health factors.
This is one reason a clinician may consider free testosterone or SHBG when total testosterone does not provide the complete clinical picture.
The Endocrine Society recommends using accurate assays and rigorously derived reference ranges when evaluating testosterone status.
Why Testosterone Reference Ranges Differ Between Laboratories
If you compare testosterone results from different laboratories, you may notice that their "normal" ranges are not identical.
That does not necessarily mean one laboratory is wrong.
Differences can result from
assay technology
calibration
reference populations
age distribution
statistical methodology
sample collection procedures
Variation between testosterone assays has historically been significant enough that researchers developed harmonization procedures to make results more comparable between laboratories.
The major harmonization study of testosterone reference ranges in men found that differences in measurement methods accounted for a substantial amount of variation between cohorts.
For that reason, the reference interval reported with your own laboratory result is generally more relevant than a generic testosterone chart found online.
Testosterone Levels in ng/dL, ng/mL, and nmol/L
Another reason testosterone charts can appear confusing is that different laboratories and countries use different measurement units.
In the United States, total testosterone is commonly reported in nanograms per deciliter, or ng/dL.
Some sources use nanograms per milliliter, or ng/mL.
Internationally, testosterone is frequently reported in nanomoles per liter, or nmol/L.
These measurements can be converted.
For example
300 ng/dL = 3 ng/mL
500 ng/dL = 5 ng/mL
700 ng/dL = 7 ng/mL
For testosterone, converting ng/dL to nmol/L can be approximated by multiplying the ng/dL value by 0.0347.
Therefore
300 ng/dL ≈ 10.4 nmol/L
500 ng/dL ≈ 17.4 nmol/L
700 ng/dL ≈ 24.3 nmol/L
To convert testosterone from nmol/L back to ng/dL, multiply by approximately 28.8.
Changing the unit does not change the person's actual testosterone level. It only changes how the measurement is expressed.
Why Is Testosterone Usually Tested in the Morning?
Testosterone concentrations can change throughout the day.
In men, testosterone is generally higher earlier in the day, with the daily variation often being more pronounced in younger adults.
This is one reason major clinical guidelines emphasize early-morning testosterone measurements when evaluating suspected male hypogonadism.
The AUA recommends obtaining at least two early-morning total testosterone measurements when evaluating testosterone deficiency.
The Endocrine Society likewise recommends confirmation using repeat morning testosterone testing.
Testing considerations in women can be more nuanced because testosterone concentrations are substantially lower and reproductive factors may also affect interpretation.
Do Testosterone Levels Change During the Menstrual Cycle?
Some variation in testosterone can occur during the menstrual cycle.
Research using LC-MS/MS found that women's testosterone concentrations were statistically higher around the middle of the menstrual cycle. However, day-to-day variation was considerable, and the researchers concluded that the menstrual-cycle differences were not clinically important enough to require cycle-specific reference intervals in that study.
This illustrates an important principle about hormone testing:
A testosterone measurement represents one point in time, not a permanent hormonal state.
What Can Cause Low Testosterone?
Age is only one potential contributor to lower testosterone levels.
Depending on the individual, testosterone can be affected by conditions involving the gonads, pituitary gland, or hypothalamus.
Other health and lifestyle factors may also influence testosterone.
In men with confirmed hypogonadism, the Endocrine Society recommends determining whether the condition is primary or secondary hypogonadism.
Primary hypogonadism primarily involves impaired testicular function.
Secondary hypogonadism involves inadequate stimulation from the hypothalamic-pituitary system.
Additional testing, including luteinizing hormone and follicle-stimulating hormone, may help distinguish between these causes.
Medications can also affect testosterone.
The Endocrine Society has identified potentially reversible contributors such as obesity and medications including opioids and corticosteroids as factors that may need consideration during evaluation.
Symptoms Associated With Low Testosterone in Men
When clinically significant testosterone deficiency is present in men, possible symptoms and signs can include:
reduced libido
sexual-function changes
reduced energy
reduced muscle mass
changes in body composition
fertility problems
reduced bone density
anemia in some cases
However, these symptoms are not unique to testosterone deficiency.
Fatigue, reduced sexual desire, changes in mood, difficulty concentrating, and changes in physical performance can have numerous potential causes.
That is why symptoms need to be evaluated alongside appropriate laboratory testing rather than being used to diagnose low testosterone on their own.
What Can Low Testosterone Mean in Women?
Interpreting lower testosterone in women is more complicated.
Women naturally have much lower testosterone concentrations than men, and testosterone generally declines with age.
A low laboratory value, however, does not automatically establish a testosterone-deficiency disorder.
The Endocrine Society has stated that there is insufficient evidence to define a generalized androgen deficiency syndrome in otherwise healthy women based simply on low androgen levels and nonspecific symptoms.
Women experiencing symptoms involving sexual health, energy, muscle or strength, menstrual function, mood, or menopause may benefit from a broader hormonal and medical evaluation.
Testosterone is only one part of that evaluation.
What Can Cause High Testosterone in Women?
Higher-than-expected testosterone in women may warrant further evaluation, particularly when accompanied by signs of androgen excess.
Possible signs can include
increased facial or body hair
acne
scalp hair changes
menstrual irregularity
other symptoms of androgen excess
The clinical significance depends on how elevated testosterone is, symptoms, medications, reproductive status, and the accuracy of the assay.
Because female testosterone concentrations are relatively low, accurate measurement is particularly important.
A clinician may investigate potential ovarian, adrenal, medication-related, or other causes depending on the individual's history and findings.
What Can Cause High Testosterone in Men?
A high testosterone result in a man can also have several possible explanations.
These can include
testosterone therapy
anabolic-androgenic steroid use
timing of testosterone medication
laboratory variation
individual physiology
less common endocrine conditions
For someone already receiving testosterone therapy, the timing of blood testing relative to a dose can substantially affect the measured concentration.
A high laboratory result therefore needs to be interpreted within the context in which the test was obtained.
Is Higher Testosterone Always Better?
No.
This is one of the most important misconceptions surrounding testosterone.
It can be tempting to assume that if testosterone within a healthy physiological range is important, then having even more testosterone must result in more:
muscle
energy
libido
confidence
athletic performance
Human physiology is more complicated.
Medical hormone treatment is not designed to create the highest possible testosterone number.
When testosterone therapy is clinically appropriate, treatment decisions should consider symptoms, laboratory findings, potential benefits, adverse effects, fertility goals, and ongoing monitoring.
Does Testosterone Always Decline With Age?
At the population level, testosterone generally decreases with age.
But individual people do not all follow the same trajectory.
Some older adults maintain testosterone concentrations within laboratory reference ranges.
Some younger adults can have low testosterone because of medical conditions, medications, obesity, pituitary or gonadal disorders, or other factors.
Age alone therefore cannot diagnose testosterone deficiency.
The Endocrine Society has emphasized that the definition of male hypogonadism should not change simply because someone is older and that normal aging should not automatically be labeled as a testosterone disorder requiring treatment.
Should Your Testosterone Be High for Your Age?
Not necessarily.
Age-related reference information can help clinicians understand how testosterone changes across populations.
But the goal is not automatically to make an older person's testosterone resemble the average level of someone decades younger.
For example, a person in their 60s does not necessarily require treatment because their testosterone is below the average observed among healthy people in their 20s.
Likewise, being "normal for your age" does not automatically rule out a medical condition.
Symptoms, repeat testing when appropriate, laboratory methodology, health history, and the underlying cause all matter.
Does a Testosterone Level Below 300 ng/dL Mean You Need TRT?
No.
The commonly cited 300 ng/dL threshold applies to the evaluation of testosterone deficiency in men. It should not be used as a treatment threshold for women.
Even in men, the AUA recommends combining a low laboratory result with appropriate symptoms or signs and confirming low testosterone on two separate early-morning measurements.
The cause of the low testosterone should also be considered.
A diagnostic cutoff is therefore part of an evaluation. It is not an automatic prescription for testosterone replacement therapy.
What About Testosterone Therapy in Women?
Testosterone therapy in women is a separate clinical issue from male testosterone replacement therapy.
A low testosterone result in a woman does not by itself establish an indication for treatment.
The Endocrine Society recommends against broadly diagnosing androgen deficiency syndrome in healthy women and against generalized testosterone use for purposes such as overall well-being, cognition, cardiovascular health, metabolic health, or bone health.
This does not mean testosterone has no potential clinical role in women's health.
It means treatment should be based on an appropriate clinical indication and individualized assessment rather than simply trying to increase a laboratory number.
Women receiving testosterone therapy also require dosing and monitoring appropriate to female physiology rather than protocols designed for men.
When Should You Have Testosterone Tested?
Testosterone testing may be appropriate when symptoms, medical history, medications, reproductive concerns, physical findings, or other clinical factors suggest an androgen-related problem.
Testing should ideally answer a clinical question rather than simply determine whether someone's testosterone is "optimal."
Depending on the situation, a clinician may evaluate testosterone alongside other laboratory markers such as
SHBG
LH
FSH
estradiol
prolactin
thyroid-related testing
other tests based on symptoms and medical history
The appropriate workup differs between men and women and depends on what condition is being investigated.
What If Your Testosterone Is Normal but You Still Have Symptoms?
A normal testosterone result does not mean symptoms should be ignored.
It also does not prove testosterone is responsible for those symptoms.
Fatigue, reduced libido, difficulty gaining muscle, mood changes, problems concentrating, sleep difficulties, and changes in weight can have many possible causes.
If testosterone testing is normal, the next step is generally to investigate other possible causes rather than automatically trying to increase testosterone.
This is particularly important because testosterone therapy is not a universal treatment for fatigue, aging, weight gain, reduced physical performance, or nonspecific symptoms.
Why You Should Not Compare Your Testosterone Level With Someone Else's
Two people of exactly the same age can have considerably different testosterone levels.
Suppose two 45-year-old men have total testosterone measurements of 420 ng/dL and 650 ng/dL.
The difference alone does not establish that the person with 650 ng/dL is healthier.
Similarly, two women of the same age can have different testosterone concentrations while both fall within an appropriate physiological range.
Interpretation may depend on
sex
symptoms
SHBG
free testosterone
medications
body composition
reproductive status
time of testing
laboratory method
underlying endocrine function
hormone therapy
Testosterone is a clinical measurement, not a competition.
Frequently Asked Questions About Testosterone Levels by Age
What are normal testosterone levels by age?
There is no universal testosterone number for each age. Testosterone changes across the lifespan, but normal ranges depend on sex, testing method, laboratory, population, and individual factors. Healthy, nonobese men ages 19 to 39 had a harmonized reference range of approximately 264 to 916 ng/dL in one major study, while women naturally have substantially lower concentrations.
What is a healthy testosterone level?
A healthy testosterone level is one interpreted in the context of age, sex, symptoms, laboratory reference range, testing method, SHBG, medications, reproductive status, and overall health. There is no single optimal testosterone number for everyone.
What are average testosterone levels by age?
Population averages generally change with age, with testosterone tending to decline across adulthood. However, an average testosterone level is not the same as a normal range, diagnostic cutoff, or treatment target.
What are normal testosterone levels for men?
A large harmonized study established a reference range of approximately 264 to 916 ng/dL among healthy, nonobese men ages 19 to 39. Reference intervals can differ between laboratories and age groups.
What are normal testosterone levels for women?
Women have substantially lower testosterone concentrations than men. One LC-MS/MS study of women ages 20 to 80 reported an overall total testosterone reference interval of approximately 0.35 to 1.97 nmol/L, with significant age-related changes.
What testosterone level is considered low in men?
The AUA uses total testosterone below 300 ng/dL as a reasonable cutoff supporting the diagnosis of testosterone deficiency. Diagnosis also requires appropriate symptoms or signs and confirmation with two separate early-morning testosterone measurements.
Is 300 ng/dL low testosterone?
In adult men, 300 ng/dL is commonly used as a clinical cutoff during evaluation for testosterone deficiency. However, a single result at or below 300 ng/dL does not automatically establish hypogonadism or mean TRT is appropriate.
Is 500 ng/dL a good testosterone level?
A total testosterone result of 500 ng/dL falls within many adult male laboratory reference intervals. However, whether a testosterone result is appropriate cannot be determined from the number alone. Sex, age, symptoms, assay, SHBG, free testosterone, medications, and clinical context all matter.
What are normal free testosterone levels by age?
Free testosterone generally decreases with age, but reference ranges depend heavily on the measurement method. One equilibrium-dialysis study reported approximately 66 to 309 pg/mL in healthy nonobese adult men overall and 120 to 368 pg/mL among men ages 19 to 39.
Does testosterone decrease with age?
Population research shows age-related declines in testosterone in both men and women. However, the degree and clinical significance vary considerably between individuals.
Do women have testosterone?
Yes. Women naturally produce testosterone and other androgens. Levels are substantially lower than in men, but testosterone is still part of normal female endocrine physiology.
Does testosterone drop after menopause?
Testosterone generally declines across women's adult lives, but menopause should not be viewed as an abrupt testosterone "off switch." Age, ovarian and adrenal function, medications, reproductive status, and hormone therapy can all influence testosterone.
Can women have low testosterone?
Women can have low measured testosterone concentrations, but a low result alone does not establish a generalized testosterone-deficiency syndrome or automatically justify testosterone therapy.
Why is testosterone tested in the morning?
Testosterone has daily variation, particularly in men. Major guidelines therefore recommend early-morning measurements when evaluating suspected male testosterone deficiency.
Should testosterone be tested more than once?
When diagnosing male hypogonadism, yes. The AUA recommends two separate early-morning total testosterone measurements, and the Endocrine Society likewise recommends confirmation of consistently low testosterone.
What is the difference between total and free testosterone?
Total testosterone includes testosterone that is protein-bound as well as testosterone circulating freely. Free testosterone represents the small fraction that is not bound to circulating proteins.
What does ng/dL mean for testosterone?
ng/dL means nanograms per deciliter. It is one of the most commonly used units for reporting total testosterone in the United States.
How do you convert testosterone from ng/dL to nmol/L?
Multiply testosterone in ng/dL by approximately 0.0347. For example, 500 ng/dL is approximately 17.4 nmol/L.
How do you convert testosterone from nmol/L to ng/dL?
Multiply testosterone in nmol/L by approximately 28.8.
Testosterone Levels by Age: The Bottom Line
Testosterone levels change throughout life, but an age-based testosterone number should be treated as clinical context rather than a universal target.
Men generally have substantially higher circulating testosterone concentrations than women. Testosterone tends to decline across adulthood in both sexes, although the pattern and clinical significance differ considerably between individuals.
The most important points to remember are:
average testosterone is not necessarily optimal testosterone
reference ranges are not treatment targets
men's and women's testosterone levels require different interpretation
total and free testosterone are different measurements
SHBG can affect testosterone interpretation
laboratory methods and reference ranges can differ
testosterone generally changes with age, but age alone does not diagnose a hormone disorder
symptoms alone do not diagnose testosterone deficiency
a single abnormal testosterone result may not provide the complete picture
treatment decisions should be based on clinical evaluation rather than an online testosterone levels by age chart
For men being evaluated for hypogonadism, major medical guidelines emphasize relevant symptoms or signs together with consistently low testosterone, rather than treating a laboratory number in isolation.
For women, testosterone interpretation requires a different clinical framework. Testosterone concentrations are naturally much lower, change across adulthood, and a generalized female androgen deficiency syndrome cannot simply be diagnosed from a low testosterone number.
At Affinity Whole Health, hormone evaluation can consider symptoms, laboratory findings, medical history, age, and individual health goals rather than relying on a single testosterone number. When treatment is clinically appropriate, therapy should be individualized and appropriately monitored.
Key Resources
Harmonized Reference Ranges for Testosterone in Men, Travison et al., 2017
Supports the 264 to 916 ng/dL reference range for healthy, nonobese men ages 19 to 39 and the percentile values used in the article. PubMedAge-Specific Testosterone Reference Ranges in Women, Haring et al., 2012
Supports the discussion of age-related testosterone changes in women and LC-MS/MS reference ranges. PubMedTestosterone Reference Ranges in Healthy Premenopausal Women, Braunstein et al., 2011
Supports the approximately 15 to 46 ng/dL total testosterone and 1.2 to 6.4 pg/mL free testosterone values for a typical 30-year-old woman. PubMedFree Testosterone Reference Intervals in Adult Men
Supports the free testosterone discussion and the importance of standardized equilibrium-dialysis measurement. PubMedEndocrine Society: Testosterone Therapy in Men With Hypogonadism
Supports morning testing, repeat testing, symptoms plus consistently low testosterone, free testosterone/SHBG considerations, and evaluation of the cause of hypogonadism. Endocrine Society SupportEndocrine Society 2026 Statement on Testosterone Replacement Therapy
Useful for the current discussion of aging versus diagnosed hypogonadism and the importance of symptoms plus consistently low testosterone. Endocrine SocietyEndocrine Society: Androgen Therapy in Women
Supports the women's health discussion, particularly why a low testosterone number alone should not be labeled a generalized female androgen-deficiency syndrome. Endocrine Society Support
Endocrine Society guidelineTestosterone Changes During the Menstrual Cycle, Bui et al., 2013
Supports the section explaining mid-cycle testosterone variation and why a single measurement may not represent overall testosterone status. PubMed
Medical Disclaimer
This article is for educational purposes only and is not a substitute for individualized medical advice, diagnosis, or treatment. Testosterone results should be interpreted using the reference range and testing method of the laboratory performing the test, together with symptoms, medical history, medications, reproductive status, and other relevant clinical information. Do not start, stop, or change hormone therapy based solely on an online testosterone range or age comparison.