Last medically updated: January 2026
This article has been revised and updated to reflect current medical findings.
This article has been medically reviewed by Dr. med. Jonathan Apasu, physician and founder of Adon Health.
Loss of energy, low libido, less muscle despite hard training? In such situations, determining your testosterone level can be the right next step. If you want to have your levels tested, you need one thing above all: reliable results. But not every test provides a equally meaningful basis. This article shows you what really matters when measuring testosterone and why blood tests, especially under certain conditions, are considered the gold standard.
Why should you test your testosterone levels?
Testosterone is the most important sex hormone in men. It influences, among other things, muscle building, fat distribution, libido, mood, and energy levels. If levels drop, for example due to age or stress, lack of sleep, poor diet, or illness, it can have far-reaching consequences (Bhasin et al., 2018). Therefore, if you have symptoms such as fatigue, lack of motivation, loss of libido, or muscle loss, you should have your hormone status checked. Even as a health check without symptoms, testing can be useful to establish an individual baseline in your healthy years and have a reliable comparison value later.
Blood test as the gold standard
Whether the Endocrine Society, American Urological Association, or the European EAU: All medical guidelines recommend measuring total and free testosterone in the blood, ideally in the morning between 7 and 10 a.m. This is crucial for a valid diagnosis (Bhasin et al., 2018; Mulhall et al., 2018; Corona et al., 2020).
Saliva and urine tests, on the other hand, provide unreliable results according to the current body of research. Concentrations in saliva fluctuate greatly, as they are influenced by numerous external factors such as saliva flow, time of day, or local enzymes. Urine tests, in turn, only detect hormonal breakdown products and not the active hormone itself, which is crucial for diagnostics (Fiers et al., 2014; Lood et al., 2018). Although the results can supposedly be determined more easily and are relatively cheap, they are hardly usable in interpretation. No therapeutic consequences can be derived from them either, as they do not meet the clinical standards for diagnosis. For these reasons, both methods are not recommended by medical professional societies for diagnosing testosterone deficiency.
Why saliva tests for testosterone are not recommended
Saliva tests are often advertised as a simple and non-invasive alternative to blood collection. In fact, they measure exclusively the portion of free testosterone that diffuses into the saliva. What sounds reasonable at first glance is problematic in clinical practice.
On the one hand, salivary testosterone levels are subject to strong fluctuations (Granger et al., 2004). They are significantly influenced by saliva flow, oral mucosa, local enzyme activity, food residue, gum inflammation, smoking, and the exact time of day the sample is taken. These factors lead to high intra-individual variability and make reproducible measurement considerably more difficult (Fiers et al., 2014).
On the other hand, saliva tests lack reliable reference ranges and standardized cut-off values. While clear cut-offs and guideline recommendations exist for blood tests, there are no universally accepted diagnostic thresholds for salivary testosterone. Accordingly, the results cannot be reliably correlated with clinical symptoms or used for a sound diagnosis (Lood et al., 2018).
It is also particularly important that no therapeutic decisions can be derived from saliva values. Neither the Endocrine Society nor the European Association of Urology or the American Urological Association recommend saliva tests for diagnosing testosterone deficiency. They are expressly not considered a basis for indicating or monitoring the progress of testosterone therapy.
Saliva tests can therefore at most be considered an experimental or scientific measurement method, but not clinically valid diagnostics. For a reliable assessment of hormone status and especially for medical decisions, the blood test remains the necessary standard (Clifton et al., 2016).
Capillary blood vs. venous blood: Which blood collection method makes sense when?
There are two established forms of blood collection for determining testosterone: capillary blood, for example via a finger prick, and venous blood, classically drawn from the arm vein. Both have their place, but also different areas of application.
Capillary blood test
In a capillary blood test, you take a small blood sample yourself from the fingertip. This method is simple, low-pain, and can be conveniently performed at home. The sample is then sent to a specialized laboratory.
One major advantage lies in its discretion and independence from a doctor's visit. You can perform the test whenever it fits into your daily life. No travel or waiting times are necessary. The method is excellent for men who want to get initial indications of their hormone status without hassle. Our capillary blood tests at Adon Health are clinically validated and measure the most important biomarkers for men's health - including total and free testosterone, SHBG, LH, and many more.
However, it is important that you perform the test in the morning on an empty stomach, as testosterone levels peak at this time (Crawford et al., 2015). You should also follow the instructions carefully and take enough time to stimulate blood flow, for example by washing your hands with warm water or doing light exercise like jumping jacks. Since the samples are sent to the laboratory by mail, it may take a little longer than venous blood collection until you receive your results. In the height of summer or winter, you should drop off the sample at a parcel shop to ensure temperature-appropriate storage and fast shipping.
More information on how to correctly perform our blood test can be found in the Step-by-Step Guide to the Testosterone Test.
Be sure to use only clinically validated home tests such as those from Adon Health. Only these guarantee an accuracy comparable to venous blood collection in medical laboratories.
Venous blood collection (classically at the doctor's, hospital, or in a direct laboratory)
Venous blood collection is the gold standard and is performed by medical professionals, usually from the arm vein in the crook of the elbow. It is a familiar standard procedure in medical practices and laboratories and requires almost no preparation. One advantage of this method is that larger quantities of blood can be drawn without the person being tested having to actively participate in the procedure.
Especially for men for whom capillary blood collection was difficult or did not yield sufficient material, venous blood collection can be a useful alternative.
However, this method is less flexible in its execution. It requires a fixed appointment and is tied to opening hours and the availability of the doctor or laboratory. This often involves waiting times, organizational effort, and additional stress. In addition, it is not always possible to take the sample exactly within the ideal time window in the early morning, which can limit the meaningfulness of the results. Many men also find the visit to the medical practice unpleasant or lacking in discretion, especially when it comes to sensitive topics such as libido, testosterone, or sexual health.
Interim conclusion:
Capillary and venous blood collections each have their own advantages. Which method is right for you depends on your personal needs. If you are looking for a discreet, flexible, and scientifically validated way to determine your hormone status conveniently from home, a capillary blood test can be ideal. It is particularly well suited for an initial assessment and can also enable more comprehensive health analyses.
Venous blood collection is especially suitable when the sample collection at home did not work well or very large quantities of blood are required. However, it requires a fixed appointment, is tied to opening hours, and can involve additional effort.
Both methods provide reliable results if performed correctly. It is important that you opt for clinically tested tests and carefully follow the application instructions.
Which values are important and why?
A simple total testosterone value is not enough to fully capture the hormonal situation. The following laboratory parameters are important for a meaningful assessment:
- Total testosterone measures the sum of all testosterone forms in the blood, i.e., free, SHBG-bound, and albumin-bound testosterone. It is the basis of every diagnosis. According to the EAU guideline, values below 12.1 nmol/L are considered an indication of hypogonadism, provided that corresponding symptoms are present (European Association of Urology, 2025).
- Free testosterone is the biologically active form. Only it can bind to receptors and acts directly on the muscles, brain, or sexual function. A normal total value can still mean too little free testosterone if SHBG is high, a so-called functional deficiency (Vermeulen et al., 1999).
- SHBG is a transport protein. The higher it is, the less testosterone is available freely. Stress, thyroid diseases, or liver conditions can influence SHBG levels (Rosner et al., 2010).
- Albumin loosely binds testosterone. This form is also bioavailable. In chronic illnesses or severe physical strain, albumin can drop, which reduces the available amount of hormone (Mazer, 2009).
- LH stimulates testosterone production in the testicles. If LH is low despite a testosterone deficiency, the problem is probably in the pituitary gland. If it is elevated, the testicles themselves are not working properly. This is important for the diagnosis of the cause (Bhasin et al., 2018).
- PSA is not a hormone, but a tumor marker. Before starting testosterone therapy, this value should be measured to rule out existing prostate cancer. PSA is also regularly measured for progress monitoring (Morgentaler et al., 2015).
For more information on the correct interpretation of your test results, this blog post is helpful.
Preparation: How to get the best out of your test
To ensure your test result is truly meaningful, you should consider the following points:
- Choose a time between seven and ten in the morning, because testosterone levels are highest during this phase (Bhasin et al., 2018).
- Also make sure not to eat anything for at least eight hours beforehand. Only water is allowed (Cleveland Clinic, 2022).
- On the morning of the test and the evening before, you should also avoid alcohol and stimulants such as caffeine.
- Illness, lack of sleep, or ongoing stress can temporarily lower your testosterone levels and distort the test results. For example, just one week of less than five hours of sleep per night can reduce testosterone levels by 10 to 15% (Leproult & Van Cauter, 2011). Chronic stress also leads to elevated cortisol levels, which can inhibit the body's own testosterone production (Gonzalez et al., 2021).
Therefore, perform the test under stable everyday conditions as much as possible, when you feel healthy and rested.
These recommendations are based on circadian hormone regulation and minimize fluctuations. You can find detailed instructions for taking our capillary blood test here.
Repeated tests for reliable diagnoses
Since testosterone levels fluctuate depending on the day and situation, for example due to stress, infections, or lack of sleep, medical guidelines generally recommend two independent tests on different days before a diagnosis is made (Bhasin et al., 2018). Whether a confirmatory test is actually necessary for a diagnosis depends on the biomarkers and results measured in the initial test, and lies within the discretion of the treating physician.
Conclusion: The best way to hormonal clarity
If you want to know how your testosterone stands, there is no way around a blood test. Capillary blood tests offer a practical, reliable, and discreet way to determine your hormone status. They provide medically relevant data, provided they are correctly applied and interpreted.
