Testosterone is one of the most important hormones affecting men's health. Its role goes beyond regulating sexual desire and reproductive function; it also contributes to muscle development, bone density, red blood cell production, and fat distribution. Although it is commonly associated with men, testosterone is also present in women at much lower levels, where it plays important roles in overall health.
Certain signs may prompt a doctor to recommend a testosterone test, such as reduced sexual desire, erectile dysfunction, decreased muscle mass, or persistent fatigue. However, these symptoms do not necessarily indicate low testosterone, as they may be associated with various physical and psychological conditions.
A testosterone test measures the level of this hormone in the blood. However, obtaining an accurate result depends on choosing the appropriate test, collecting the blood sample at the right time, and interpreting the results in light of symptoms and the laboratory's reference range.
In this article, we explore the different types of testosterone tests, why they are performed, and how to interpret testosterone levels in men and women.
Types of Testosterone Tests
When requesting a testosterone test, your doctor may recommend measuring total or free testosterone, or sometimes both. Understanding the difference is important because each test measures a different portion of the hormone in the blood.
Total Testosterone Test
A total testosterone test measures the overall amount of testosterone in the blood, including:
- Testosterone bound to blood proteins, such as sex hormone-binding globulin (SHBG) and albumin.
- Free testosterone, which is the portion not bound to proteins.
Total testosterone is usually the initial test used when low testosterone is suspected in men. The American Urological Association (AUA) guidelines use a level below 300 ng/dL as a reference threshold supporting the diagnosis, provided that compatible symptoms or signs are present and the low level is confirmed through two separate morning measurements.
Free Testosterone Test
A free testosterone test measures the portion of testosterone that is not bound to blood proteins and is available to body tissues.
A doctor may request this test when the total testosterone result is inconclusive or when certain factors may affect the level of hormone-binding proteins, such as changes in SHBG.
It is important to understand that total and free testosterone are not interchangeable tests. One should not be substituted for the other without medical guidance. Your doctor determines the appropriate test based on your condition and may also request SHBG measurement or calculate free testosterone using other test results when necessary.
What Is Testosterone and What Does It Do?
Testosterone is an androgen hormone produced primarily in the testicles in men, with smaller amounts produced by the adrenal glands. In women, it is produced in much lower quantities by the ovaries and adrenal glands.
Testosterone production increases during puberty in males, contributing to the development of secondary sexual characteristics. It continues to perform several important functions throughout life.
The main functions of testosterone include:
- Development of male characteristics: It contributes to the growth of reproductive organs, facial and body hair, and voice deepening during puberty.
- Supporting sexual desire: It plays a role in regulating libido in both men and women.
- Maintaining muscle mass: It helps build muscle and preserve muscle strength.
- Supporting bone health: It contributes to maintaining bone density and reducing the risk of bone weakness.
- Sperm production: It works within a broader hormonal system that regulates testicular function and sperm production.
- Red blood cell production: It contributes to regulating red blood cell production in the body.
- Fat distribution: It affects the distribution of body fat and muscle mass in men.
When testosterone levels become abnormal, changes in some of these functions may occur. A testosterone test can help assess hormone levels, but the results must always be interpreted alongside symptoms and a medical evaluation.
Low Testosterone Symptoms in Men
Low testosterone may cause a range of symptoms. Their severity varies from person to person depending on the hormone level, how long it has been low, and the individual's overall health.
Some of the most common low testosterone symptoms that may lead a doctor to recommend a testosterone test for men include:
- Reduced sexual desire: A man may notice a persistent and significant decrease in his interest in sexual activity.
- Erectile dysfunction: Low testosterone may be associated with erection problems, although it is not the only possible cause.
- Fewer morning erections: Some men may notice a decrease in spontaneous erections upon waking.
- Persistent fatigue: A person may feel tired and lack energy even after getting enough sleep.
- Reduced muscle mass: Maintaining muscle may become more difficult, accompanied by a decline in physical strength.
- Increased body fat: Some men may experience increased body fat, particularly when physical activity decreases.
- Mood and concentration changes: Symptoms may include difficulty concentrating, reduced motivation, or feelings of sadness.
- Reduced bone density: Persistent testosterone deficiency may be associated with a higher risk of weakened bones.
- Reduced fertility: Sperm production may be affected by hormonal dysfunction.
However, having one or more of these symptoms does not confirm low testosterone. Fatigue, sleep disturbances, and erectile dysfunction, for example, may also be associated with diabetes, cardiovascular disease, thyroid disorders, stress, or certain medications.
Therefore, symptoms alone should not be used to diagnose testosterone deficiency. A doctor determines whether a testosterone test or additional investigations are needed to identify the possible cause.
Normal Testosterone Levels in Men
Normal testosterone levels vary depending on age, sex, test type, measurement method, and laboratory. There is no single value that can be considered normal for everyone, so the reference range provided in the laboratory report should be reviewed first.
According to the American Urological Association (AUA) guidelines, a total testosterone level below 300 ng/dL is used as a reference threshold that supports suspicion of testosterone deficiency. However, this result alone is not sufficient to establish a diagnosis.
The following points should be considered:
- If the result is below 300 ng/dL, it may indicate low testosterone, but it must be evaluated alongside symptoms and clinical findings.
- If the result is close to the reference threshold, the doctor may recommend additional assessment, such as measuring free testosterone or SHBG, depending on the individual's condition.
- If the result falls within the reference range, this does not necessarily mean that all symptoms are unrelated to hormones. Other causes may still require investigation.
Some medical guidelines and references use different thresholds when evaluating low testosterone, ranging approximately from 230 to 350 ng/dL, depending on the measurement method and clinical context. Therefore, no single number should be considered the universal normal testosterone level for all men.
Normal Testosterone Levels in Women
Testosterone levels in women are significantly lower than those in men. Their interpretation depends on age, life stage, measurement method, and the laboratory's reference range.
A doctor may request a testosterone test when signs of elevated androgens appear, such as increased hair growth in unusual areas, severe acne, or irregular menstrual cycles.
In all cases, testosterone results should not be interpreted separately from symptoms and medical history. High or low levels may require additional tests to determine the underlying cause.
How Is a Testosterone Test Performed?
A testosterone test is performed by collecting a blood sample from a vein. The procedure usually does not require complicated preparation, but the timing of sample collection is particularly important when evaluating testosterone levels in men.
Before the test, it is advisable to inform your doctor or laboratory about any medications and supplements you take, especially hormonal medications or treatments that may affect testosterone levels.
You should also tell your doctor if you have an acute illness or a sleep disorder, as certain health conditions may temporarily affect hormone levels.
What Is the Best Time to Take a Testosterone Test?
Testosterone levels fluctuate throughout the day and are generally higher in the morning than in the afternoon or evening, particularly in younger men.
For this reason, a morning blood sample is preferred when evaluating possible testosterone deficiency in men. The sample is usually collected during the early hours after waking up.
Timing matters because a testosterone test performed later in the day may show a lower level than a morning test, potentially affecting how the result is interpreted.
It is also preferable to undergo testing when your health is relatively stable, as acute illness and sleep disturbances may affect testosterone levels.
Should You Repeat a Testosterone Test?
Low testosterone should not be diagnosed based on a single low result. Temporary factors such as insufficient sleep, illness, or the time of blood collection may affect the reading.
The AUA guidelines recommend confirming low testosterone through two morning measurements taken on separate days, alongside the presence of compatible symptoms or signs.
Repeating the testosterone test helps determine whether the low level is persistent rather than a temporary change. It also gives the doctor a more reliable basis for deciding whether additional tests are needed.
Factors That May Affect Testosterone Levels
Testosterone levels may change due to health conditions, lifestyle factors, or medications. These factors should be considered when interpreting test results.
Some of the main factors that may affect testosterone levels include:
- Age: Testosterone levels may gradually decrease in some men as they get older, although the decline is not the same for everyone.
- Poor sleep: Sleep disorders and insufficient rest may affect hormone production.
- Obesity: Excess weight and metabolic disorders are associated with lower testosterone levels in some men.
- Acute illnesses: Certain illnesses and severe infections may temporarily reduce testosterone levels.
- Chronic diseases: Some health conditions, including liver disease, kidney disease, and diabetes, may affect hormonal balance.
- Certain medications: Some medications, such as opioid painkillers and certain corticosteroids, may affect testosterone production.
- Hormone and steroid use: Anabolic steroids and some hormonal preparations may disrupt the body's natural hormone production.
- Stress and physical strain: Sleep disturbances and psychological stress may interact with the factors that regulate hormone production.
If a testosterone test shows an unexpected result, your doctor may recommend repeating the test or performing additional investigations to identify the cause rather than making a decision based on a single reading.
High Testosterone Levels in Women: Causes and Symptoms
Although testosterone is commonly known as the male sex hormone, it is also present in women and contributes to regulating sexual desire and certain physiological functions. However, levels higher than expected may indicate a hormonal disorder that requires medical evaluation.
One of the conditions associated with elevated androgens in women is polycystic ovary syndrome (PCOS), which may affect menstrual regularity and ovulation.
A doctor may request a testosterone test for women if symptoms such as the following appear:
- Unusual or excessive hair growth on the face or body.
- Persistent or severe acne.
- Irregular menstrual periods.
- Scalp hair loss in a pattern that may be associated with elevated androgens.
- Difficulty becoming pregnant due to ovulation problems.
Elevated testosterone alone is not enough to diagnose PCOS. Diagnosis depends on a combination of clinical and hormonal criteria. The doctor may also need to assess ovulation and rule out other causes of elevated androgen levels.
Testosterone measurement in women requires accurate testing methods because hormone levels are relatively low. Some measurement methods may not be sufficiently accurate for assessing these lower concentrations.
Testosterone and Male Fertility: Which Tests Are Needed?
Testosterone plays an important role in male reproductive function. It contributes to regulating testicular activity and affects the hormonal environment required for sperm production.
However, it is important to distinguish between measuring testosterone in the blood and assessing sperm quality. Each test answers a different medical question.
- Testosterone test: Assesses the level of testosterone in the blood and may identify hormonal disorders that affect reproductive function.
- Semen analysis: Evaluates sperm count, movement, and shape. It is one of the basic tests used to assess male fertility.
- Other hormone tests: Depending on symptoms and initial results, the doctor may request tests for hormones such as FSH, LH, and prolactin.
One important point is that external testosterone use, whether through injections or other preparations, may suppress the hormones that regulate testicular function. This can reduce sperm production and, in some men, may even lead to the absence of sperm.
Therefore, testosterone should not be used to improve fertility or treat unexplained symptoms without medical assessment. A specialist should evaluate the condition before any treatment decision is made.
Book Your Testosterone Test at Nawat Advanced Medical Laboratory
Monitoring hormonal indicators is an important part of maintaining overall health, particularly when symptoms may be associated with abnormal testosterone levels. Choosing the appropriate tests and collecting samples at the right time can provide more accurate information for your doctor to assess your condition.
Nawat Advanced Medical Laboratory offers a range of medical laboratory services that help assess health and hormonal indicators according to the available tests and each individual's needs.
If your doctor recommends a testosterone test, you can inquire about the test details, sample collection procedures, and the available services included in the Men's Health profile.
Take care of your health and monitor your hormonal indicators through the medical testing services at Nawat Advanced Medical Laboratory. Book the tests that are appropriate for you based on your doctor's recommendation.
Frequently Asked Questions
1. How do my testosterone test levels?
Your testosterone test results show the amount of testosterone in your blood, usually measured in ng/dL. Your doctor interprets the result based on your age, symptoms, and the laboratory's reference range.
2. What is normal testosterone by age?
Normal testosterone levels vary with age, testing method, and laboratory reference ranges. There is no single range that applies to everyone, so a testosterone test at Nawat Advanced Medical Laboratory can help assess your level accurately.
3. Which level of testosterone is high?
A testosterone level is considered high when it exceeds the reference range for the person's age and sex. The interpretation also depends on symptoms and other clinical findings, so discuss your testosterone test results with your doctor.
4. What is a testosterone test done for?
A testosterone test measures hormone levels to help investigate symptoms such as low sex drive, erectile dysfunction, fatigue, or fertility problems. It may also help assess hormonal disorders in women when elevated testosterone is suspected.
5. What are 10 signs of low testosterone?
Common signs include low sex drive, erectile dysfunction, fewer morning erections, fatigue, reduced muscle mass, increased body fat, mood changes, poor concentration, reduced bone density, and fertility problems. A testosterone test at Nawat Advanced Medical Laboratory can help assess hormone levels when recommended by your doctor.
Conclusion
A testosterone test is an important tool for assessing male hormone levels and identifying hormonal disorders that may affect sexual, reproductive, and physical health. However, low testosterone should not be diagnosed based on a single test result. A proper diagnosis requires compatible symptoms and confirmation of low levels through two separate morning measurements.
Therefore, make sure to take the test at the appropriate time and discuss the results with your doctor to determine the next steps. Nawat Advanced Medical Laboratory provides medical testing services that help you monitor hormonal indicators and take care of your health.
Trusted Medical References
- American Urological Association (AUA): Evaluation and Management of Testosterone Deficiency
- Sexual Medicine Society of North America (SMSNA): Diagnosing Testosterone Deficiency in Men
- Urology Care Foundation: How the New AUA Guideline on Testosterone Deficiency May Impact You