Testosterone: symptoms, blood values and what affects your level

Your deadlift has stalled for two blocks, your libido is flat, and the alarm feels heavier every morning. The easy conclusion is "my testosterone is low". But before you order a supplement: a single number from the lab says surprisingly little. The real story sits in five values together, and in how you live.

My stance is simple: do not start with a pill, start with a measurement. Without a baseline you are shooting in the dark.

What is testosterone and what does it do?

Testosterone is your main androgenic hormone. It drives libido, muscle mass, bone density, red blood cell production and mental drive. Men make it mostly in the testes, pushed by LH and FSH from the pituitary.

Most of your testosterone is bound to proteins and is not directly active. Only the free fraction can actually be used by your tissues. That is exactly why a single total value can put you on the wrong track. The Endocrine Society stresses in its hypogonadism guideline that a diagnosis should never rest on one measurement or on symptoms alone.

What are the symptoms of low testosterone?

Low testosterone can show up as ongoing fatigue, lower sex drive, stalling muscle gains, more belly fat, irritability and poor concentration. The problem: these complaints are not very specific. Sleep loss, stress and a shortage of iron or vitamin D often produce the same picture.

That is why you cannot pin down low testosterone on feel alone. What you notice as an energy dip could just as easily come from your sleep. Which complaints really fit a low level is covered in low testosterone symptoms in men.

Which blood values say something about your testosterone?

One value is rarely enough. A solid hormone picture combines five markers. Use the reading guide below as a decision aid: per symptom or question you see which marker helps most and what it adds.

The deeper explanation of total versus free is in free testosterone and SHBG. To learn how to interpret your own numbers, read understanding your testosterone levels.

Why a single number puts you on the wrong track

Imagine two men both have a total testosterone of 14 nmol/l. One feels great, the other drags himself through the week. The difference sits in their SHBG and free fraction. With a high SHBG, a larger part of that 14 is bound and therefore unusable, leaving less active hormone. That is why it is so risky to judge a result on the total alone. You read a snapshot, not a full picture.

On top of that, testosterone drops during the day. A draw at two in the afternoon can come out 20 to 30 percent lower than a morning measurement. Anyone who draws their value at the wrong moment quickly reaches the wrong conclusion. The practical side of timing and preparation is in how to test testosterone.

Primary or secondary: where is the problem?

If your testosterone is low, the next question is: where does it go wrong? Here LH becomes your most important compass. Your pituitary sends LH to the testes to push production. The combination of your testosterone and your LH tells you where the bottleneck sits.

• Low testosterone with high LH: your pituitary is calling loudly, but the testes do not respond well. This is called primary hypogonadism.
• Low testosterone with low or normal LH: the signalling from your brain is reduced. This is called secondary hypogonadism and can be linked to excess weight, sleep problems or a raised prolactin, among other things.

That distinction shapes the next step and belongs with your doctor. It does illustrate why a hormone panel is worth more than a single testosterone measurement: without LH you miss half the story.

What affects your testosterone?

Your level depends on age, sleep, body fat, resistance training, alcohol and chronic stress. Sleep is the most underrated factor: chronically short sleep can noticeably depress your value. A high body-fat percentage matters too, because fat tissue converts testosterone into estradiol through aromatase.

The decline with age is real, but slow. The Dutch Health Council (Gezondheidsraad) points out in its lifestyle advice that enough exercise, a healthy weight and moderate alcohol use form the foundation of your hormonal health. For most men under fifty, sleep, training and body composition are the dials you can actually turn. How to do that without empty promises is covered in increasing testosterone naturally.

What strikes me as a training partner: men underestimate how strongly their weight and sleep turn these dials, and overestimate what a supplement can do. Someone who loses ten kilos of belly fat and goes from five to eight hours of sleep often changes more about their hormone picture than any booster. So the order is: basics first, fine-tuning later.

How exactly do sleep, alcohol and training fit in?

Sleep is about more than hours. Most of your daily testosterone production happens during the deep sleep stages in the second half of the night. Chronically sleeping under seven hours can depress your value by ten to fifteen percent in studies, without you consciously noticing. Sleep hygiene is therefore not a lifestyle footnote but a direct link in your hormone production chain.

Alcohol has a comparable direct effect. Regularly drinking more than two standard drinks per evening raises your cortisol and temporarily suppresses testosterone production in the testes. An occasional glass is not a problem for most men, but drinking heavily every day is one of the fastest ways to undermine your hormonal foundation.

Resistance training supports testosterone production most when you train compound movements, think squats, deadlifts and bench press, with sufficient load but also enough recovery space. The Gezondheidsraad recommends at least 150 minutes of moderate exercise per week as the basis for general health; for active athletes, the ratio between training load and recovery also counts.

What role does estradiol play in men?

Estrogen sounds like a women's hormone, but men need it just as much. Estradiol arises partly from testosterone through the enzyme aromatase and plays a role in your bones, your libido and your fat distribution. Too little estradiol can cause joint complaints and a low libido, too much can cause fluid retention and mood swings.

In men with a lot of fat tissue, aromatase activity can be higher, so relatively more testosterone is converted into estradiol. That is one of the reasons why your body-fat percentage weighs so heavily in the overall picture. Estradiol therefore belongs in a complete hormone panel, not as a side issue but as part of the balance.

Testosterone and age: what is normal?

Many men are alarmed by the idea that testosterone declines over the years. The decline is real, but on average slow, roughly 1 to 2 percent a year from age thirty. More important than your age is how you live. A fit fifty-year-old with a healthy weight and good sleep often has better values than a forty-year-old who sleeps badly and is overweight.

For longevity that is good news: you have more influence than you think. At the same time, a high testosterone is not a goal in itself. The balance with other markers and your overall health weighs more than a record number. A sensible aim is a healthy, stable value that fits how you feel and perform, not chasing the top of the range.

How do you get your testosterone tested?

Testosterone is best measured in the morning, because your level peaks then and falls during the day. A single reading says less than two readings on different days. A hormone panel measures several values at once, so you keep the context.

You can have your values measured with the General Hormones panel. If you already use testosterone therapy, the TRT Monitoring panel makes more sense. The practical side, from timing to preparation, is in how to test testosterone.

Testosterone and your recovery as an athlete

For anyone who trains seriously, testosterone is not an abstract number but a recovery currency. The hormone helps with protein synthesis, the production of red blood cells and your motivation to take on the heavy sessions. When your level drops, you often notice it in your recovery before you notice a symptom from a leaflet: sessions feel heavier, progress stalls and the drive to hit the gym disappears.

At the same time it works the other way too. Training too hard and too long without enough recovery can actually depress your testosterone and raise your cortisol. Overtraining is not a badge of honour but a brake. Those who measure their values a few times a year see this pattern earlier than those who go on feel alone. That is exactly the gain of data: you can adjust your training load before you hit a wall.

Four stubborn misconceptions

A lot of half-truths float around testosterone. A few I hear often, and what is actually true:

• "A booster raises my testosterone." Most over-the-counter boosters show barely any effect in research. Sleep, weight and training do far more.
• "My value is low, so I need therapy." Not necessarily. A low number without complaints, or a low number caused by a correctable lifestyle, first calls for getting the basics in order.
• "One measurement is enough." Testosterone fluctuates by day and by moment. You repeat one deviating result before drawing conclusions.
• "The higher, the better." A high testosterone is not a goal in itself. The balance with estradiol, hematocrit and your overall health weighs more than a record number.

My stance here: most of the gain for the average athlete sits not in a higher ceiling, but in removing the brake that sleep loss, excess weight and alcohol put on your value.

When to see a doctor?

Goal: know what your values are doing. But a test panel does not replace a doctor. The Dutch College of General Practitioners (NHG) advises assessing persistent complaints such as fatigue, loss of libido or erection problems in context, alongside other causes. If you have stubborn complaints or your values clearly deviate, discuss your results with your GP before changing anything.

Reading your panel: three common patterns

When your result is in, it helps to read your values as a pattern rather than as loose figures. Three patterns we often see in active men:

• Normal total, low free, high SHBG: you have enough testosterone, but a large part is bound. This explains complaints despite a "normal" result.
• Low total, high LH: your pituitary is signalling hard, but the testes lag behind. This always belongs with your doctor.
• Low total, low or normal LH, high body fat: often a lifestyle picture where weight, sleep and alcohol play the biggest role.

These patterns are not a diagnosis, but they help you have a more focused conversation with your doctor. How to read each number separately is in understanding your testosterone levels.

Keep reading in this series

• Low testosterone in men: symptoms and matching blood values.
• Understanding your testosterone levels: how to read your numbers.
• Testing testosterone: how, where and when.
• Free testosterone and SHBG: what your values really mean.
• Increasing testosterone naturally: what actually works.

My advice stands: do not start with a supplement, start with a morning draw and a full hormone panel. That baseline is the value you can test every later choice against.

Disclaimer

Every blood test result includes a professional assessment by a BIG-registered doctor. This article gives general information and cannot replace medical advice. A blood test is a tool to enter the conversation with your GP better informed, not a diagnosis in itself. Always discuss treatment decisions with your doctor.