Testosterone

What is testosterone?

Testosterone is an androgen hormone that is produced primarily in the testicles of men. In women, the ovaries and adrenal glands produce smaller amounts. Additionally, the body can produce testosterone through the conversion of androstenedione in peripheral tissues, such as fat and muscle tissue.

The majority of testosterone in the blood is bound to a protein called SHBG (sex hormone-binding globulin). Only one to two percent circulates freely in the blood. Only this free portion is directly biologically active. In the tissues, testosterone can be converted into dihydrotestosterone, an even more potent active form, or into estrogen in fat tissue.

In most men, the hormone reaches its highest level around the age of twenty-five. After that, production gradually declines. From around the age of forty, a slight annual decline is very common and is part of the normal aging process.

What role does testosterone play in the body?

Testosterone influences a wide range of physical and mental functions. The hormone supports the building and maintenance of muscle mass, contributes to strong bones, and plays a key role in sexual functioning. Both men and women experience the consequences of an imbalance in this hormone.

In addition to physical effects, testosterone also influences mood and motivation. A healthy level helps you feel energetic, contributes to a positive state of mind, and supports perseverance during physical exertion. This makes testosterone not only a reproductive hormone but also a hormone that relates to daily well-being.

In women, testosterone helps regulate fat distribution, muscle mass, and libido. In women, a disruption in the testosterone balance can be associated with irregularities in the menstrual cycle or changes in estrogen production.

What do abnormal values ​​mean?

In men, a value above 12 nmol/L is generally considered normal. Values ​​below 8 nmol/L indicate a deficiency, also known as hypogonadism. The zone between 8 and 12 nmol/L is a grey area where symptoms and context determine whether treatment is worthwhile.

A testosterone level that is too low can manifest in various ways. Common signs include:

• Reduced or absent libido
• Fatigue and low energy levels
• Loss of muscle mass and increase in body fat
• Depression, irritability, or mood swings
• Sleep problems
• In men: fewer morning erections or erection problems
• Reduced bone density in the long term

In women, abnormal testosterone levels may indicate a hormonal imbalance. Both low and high levels are relevant. High levels in women may be associated with conditions such as polycystic ovary syndrome (PCOS).

When and how to get measured?

A testosterone test is useful for persistent symptoms consistent with a hormonal imbalance, such as unexplained fatigue, changes in body composition, mood complaints, or fertility problems. Testosterone is also regularly measured when monitoring hormone treatment.

For men, it is important to have a fasting blood sample taken in the morning. Testosterone follows a distinct diurnal rhythm, with the highest values ​​early in the morning and the lowest around midnight. Furthermore, the level drops by approximately thirty percent in the hours following a morning meal. Therefore, a fasting morning measurement provides the most reliable result.

For women, the day of the menstrual cycle plays a greater role than the time of day or being fasting. Anyone wishing to have the result assessed should provide this information, along with their cycle data, to their doctor or healthcare provider for correct interpretation.