Testosterone Blood Tests vs. Urine Tests
Which is Best for Measuring Testosterone Levels?
Testosterone is a key hormone that plays a crucial role in various bodily functions, including muscle growth, bone density, mood regulation, and reproductive health. Whether you're experiencing symptoms of low testosterone (low T) or monitoring hormone levels for health or performance reasons, choosing the right testosterone test is essential.
This article explores the differences between testosterone blood tests and urine tests, including their accuracy, reliability, and best use cases. Additionally, we’ll cover saliva testing and other relevant hormone assessments. All information is supported by authoritative medical sources.
Types of Testosterone Tests
There are three main ways to measure testosterone levels:
- Blood tests (serum testosterone tests)
- Urine tests (24-hour urinary testosterone tests)
- Saliva tests (used less commonly but still available)
Each method has its strengths and weaknesses, which we will break down in detail.
Testosterone Blood Tests: The Gold Standard
How Blood Testing Works
A serum testosterone test measures the levels of testosterone circulating in your bloodstream. It is typically conducted in the morning when testosterone levels are at their peak. Blood tests can evaluate different types of testosterone, including:
- Total testosterone – the combined amount of free and bound testosterone in the blood.
- Free testosterone – the portion of testosterone that is unbound and available for use by the body.
- Bioavailable testosterone – free testosterone plus testosterone weakly bound to albumin, which is also available for the body's use.
Advantages of Blood Tests
- Most accurate and widely accepted method. Blood tests are the standard recommended by major medical organizations, such as the Endocrine Society and the American Urological Association [¹][²].
- Measures different testosterone fractions. Unlike urine tests, blood tests can differentiate between total, free, and bioavailable testosterone.
- Quick and convenient. A simple blood draw from a vein is sufficient, and results are typically available within a day.
Limitations of Blood Tests
- Snapshot measurement. Blood tests only reflect testosterone levels at a single point in time, which can fluctuate throughout the day.
- Potential variability. Testosterone levels naturally peak in the morning and decrease throughout the day, so testing time is crucial for accuracy.
Who Should Get a Blood Test?
A blood test is ideal for:
- Individuals experiencing symptoms of low testosterone, such as fatigue, low libido, or muscle loss.
- Those undergoing testosterone replacement therapy (TRT) to monitor hormone levels.
- Athletes or bodybuilders who want a clear baseline measurement of their testosterone levels.
Testosterone Urine Tests: Are They Reliable?
How Urine Testing Works
A 24-hour urine test measures the total amount of testosterone excreted in urine over an entire day. This method provides an average testosterone level rather than a single time-point measurement.
Advantages of Urine Tests
- Reflects a full day’s testosterone production. Unlike blood tests, which only measure a single moment in time, urine tests capture hormone fluctuations throughout the day.
- Less invasive. No needles are required, making it a more comfortable option for some people.
Limitations of Urine Tests
- Less precise for diagnosing low T. The Endocrine Society does not recommend urine testing for diagnosing testosterone deficiencies because it is less accurate than blood tests [³].
- Does not differentiate between free and bound testosterone. Urine tests only provide a total testosterone measurement, making them less useful for detailed hormonal assessments.
- Inconvenient sample collection. Collecting urine over a full 24-hour period can be cumbersome and prone to errors.
Who Should Get a Urine Test?
Urine testing may be useful for:
- Research purposes where long-term testosterone levels are being analyzed.
- Checking hormone metabolism alongside other steroid hormone levels.
- Certain clinical cases, such as adrenal function testing.
However, for most individuals concerned about testosterone levels, blood tests are a better choice.
Saliva Testosterone Tests: Are They Worth It?
How Saliva Testing Works
A saliva test measures the amount of free testosterone present in saliva. Some online hormone testing companies market saliva tests as a convenient at-home option.
Advantages of Saliva Tests
- Easy, non-invasive collection. No blood draw is required.
- Can measure free testosterone. Since saliva reflects free testosterone levels, it can be useful for research.
Limitations of Saliva Tests
- Less reliable and not widely recommended. According to the American Urological Association, saliva testing lacks standardization and is not considered a diagnostic tool for testosterone deficiency [²].
- Subject to contamination. Eating, drinking, and oral health conditions can affect results.
Who Should Get a Saliva Test?
- Researchers studying testosterone fluctuations in various populations.
- Those looking for at-home testing options (though blood tests remain superior).
Additional Hormone Tests for a Complete Assessment
Besides testosterone, doctors often recommend additional tests to get a full picture of hormonal health:
- Sex Hormone-Binding Globulin (SHBG): Determines how much testosterone is bound in the bloodstream.
- Luteinizing Hormone (LH) & Follicle-Stimulating Hormone (FSH): Helps diagnose causes of low testosterone, such as pituitary gland dysfunction.
- Dihydrotestosterone (DHT): Measures levels of the potent androgen that testosterone converts into.
- Estradiol (E2): Important in men since high estrogen levels can result from testosterone imbalances.
Which Testosterone Test Is Right for You?
| Factor | Blood Test | Urine Test | Saliva Test |
|---|---|---|---|
| Accuracy | ✅ Most accurate | ❌ Less accurate | ❌ Not recommended for diagnosis |
| Measures Total Testosterone | ✅ Yes | ✅ Yes | ❌ No |
| Measures Free Testosterone | ✅ Yes | ❌ No | ✅ Yes |
| Convenience | ⚠ Requires blood draw | ❌ 24-hour collection required | ✅ At-home collection |
| Recommended for Low T Diagnosis? | ✅ Yes | ❌ No | ❌ No |
Key Takeaway:
- For diagnosing low testosterone, a blood test is the best option.
- Urine tests may help in research or adrenal hormone assessments but are not recommended for diagnosing low T.
- Saliva tests are not widely accepted for clinical use.
If you suspect low testosterone, consult a doctor for a blood test and a complete hormonal evaluation.
Footnotes & Citations
- The Endocrine Society. “Testosterone Therapy in Men with Hypogonadism: An Endocrine Society Clinical Practice Guideline.” The Journal of Clinical Endocrinology & Metabolism, 2018. Available here
- American Urological Association. “Evaluation and Management of Testosterone Deficiency.” AUA Guidelines, 2018. Available here
- Mayo Clinic. “Testosterone tests: Why they’re done and what they measure.” Mayo Clinic, 2022. Available here
