Testosterone testing: what it measures and when it makes sense

When can a testosterone test be worthwhile?

Men who consider a testosterone test often recognise the same list: less energy than before, a lower sex drive, a gloomy undertone or the feeling that muscle mass is declining despite training. These complaints can fit low testosterone, and that is exactly when measuring can be worthwhile: it replaces guessing with a concrete value.

At the same time, honesty is due here: these complaints are non-specific. They are at least as often caused by something else:

• too little or irregular sleep
• prolonged stress, at home or at work
• little exercise or, conversely, overtraining
• another physical cause, such as an underactive thyroid or low iron stores

A testosterone test does not rule out those other explanations. If you already know your sleep has been poor for months, that knowledge is often worth more than a laboratory result. If complaints persist despite a normal daily pattern, a measurement can help bring the hormonal part of the story into view.

What does testosterone do in the body?

Testosterone is the primary male sex hormone and also plays a role in women, albeit in smaller amounts. It influences muscle mass, fat distribution, bone density, libido and partly also mood and energy. In men it is produced mainly in the testes, directed by hormones from the brain.

As men get older, the level declines gradually. That is a normal course and causes no noticeable complaints in most men. A value that is remarkably low for one's age, certainly in combination with fitting complaints, is a reason for a doctor to look further.

How the measurement works: draw blood in the morning

Testosterone follows a daily rhythm: the level is highest in the morning and drops over the course of the day. A draw later in the day can therefore come out lower without anything being wrong. For a representative measurement, Bloodworks therefore recommends a morning blood draw.

The value also fluctuates from day to day. Poor sleep, illness, intensive training or a stressful period can temporarily push the result down. If a first measurement comes out low, a second morning measurement at another moment is customary before conclusions are drawn; that judgement lies with the reviewing doctor.

Why SHBG helps: total and free testosterone

The most commonly measured value is total testosterone: all the testosterone in the blood combined. Most of it is bound to proteins, mainly to SHBG (sex hormone-binding globulin). Only the unbound part, free testosterone, is directly available to the tissues.

That is why measuring SHBG alongside helps. Free testosterone is calculated from total testosterone and SHBG. A total value that looks normal can therefore still go hand in hand with little freely available testosterone when SHBG is high, and the other way around. SHBG also changes with age and under the influence of, among other things, weight and thyroid function.

In a complete hormone panel, total testosterone, SHBG and the calculated free testosterone are combined with LH and FSH, the hormones from the brain that drive production. That coherence helps the doctor see where any abnormality originates.

What the result does and does not tell you

A single result is a snapshot. The value says something about that one morning, not about your entire hormone balance throughout the year. Age matters too: what is usual for one phase of life is not usual for another.

That is why a doctor always interprets the result in context: the level itself, its relation to SHBG, LH and FSH, your age and your complaints. A value within the usual range does not dismiss complaints, and a lower value is not a diagnosis in itself. At Bloodworks, every result therefore comes with a personal explanation from a doctor.

Lifestyle as the first lever

If you want to support your own testosterone level, start with lifestyle. Sufficient and regular sleep does a lot: production takes place mainly during sleep, and structural sleep deprivation pushes the level down.

Strength training and sufficient exercise have a favourable effect, as does reducing considerable excess weight. Heavy alcohol use works in the opposite direction. These are not quick fixes, but they are the levers you can operate yourself, and they also improve sleep, energy and mood through other routes.

No self-medication: therapy belongs with a treating doctor

Supplementing testosterone on your own initiative, through supplements, gels or injections from outside regular care, is not a good idea. Supplementation or therapy should take place exclusively through a treating doctor, who first investigates whether there really is a deficiency, rules out other causes and monitors the use.

Self-medication carries risks: the body can reduce its own production, and products of unknown origin have no control over content or dosage. Bloodworks measures and has the result reviewed by a doctor, but does not treat and does not promote testosterone therapy.

A testosterone test passes no judgement on your masculinity and offers no ready-made explanation for all your complaints. What the measurement does is replace guessing with knowing: you see where you stand and whether the hormonal track deserves further attention.

Have blood drawn in the morning, include SHBG for the calculated free testosterone and discuss an abnormal result with a doctor. That keeps the order clean: first measure and interpret, only then act.