Testosterone and doping in Sweden – what happens in the body

Quick version

Testosterone is the most common doping drug in Sweden and is also increasingly used as a treatment, especially among older men. The hormone affects muscles, energy and sex drive, among other things, but when it is administered externally, the body's own production can be shut down. This can lead to side effects such as reduced testicles, reduced fertility and increased strain on the heart. At the same time, many people are treated with testosterone without actually having a deficiency, which makes its use a growing gray area between medicine and performance enhancement.

An estimated 50,000 to 100,000 people in Sweden use doping substances – and in the vast majority of cases, it involves testosterone. At the same time, the medical use of the hormone is also increasing, particularly among men over the age of fifty. But what actually happens in the body when testosterone levels are artificially elevated?

Testosterone – the body’s central sex hormone

Testosterone is a hormone primarily produced in the testicles in men and in smaller amounts in the ovaries in women. The hormone plays an important role in, among other things:

muscle mass and strength
bone density
sex drive (libido)
energy levels and well-being

Although testosterone is most commonly associated with men, it is important for both sexes.

Why testosterone is used for doping

Testosterone is the most common doping substance, largely due to its clear effects on the body, such as increased muscle growth, faster recovery, and improved physical performance. These effects make the hormone attractive both in sports and among individuals looking to change their body composition.

But what happens in the body when testosterone is introduced?

When the body is supplied with testosterone from external sources, it responds by reducing or completely shutting down its own production of the hormone. This is a central mechanism that is often overlooked when the short-term goal is to quickly achieve desired effects such as increased muscle mass or performance.

The consequences of testosterone doping may include:

reduced natural hormone production
shrinkage of the testicles
impaired fertility

This occurs because the body’s hormonal system is regulated through a finely tuned feedback mechanism.

Increased risk of side effects

Elevated testosterone levels can affect multiple organs and systems in the body. Some of the most well-known risks include:

changes in blood profile – the blood can become more viscous
increased strain on the heart and blood vessels
hormonal imbalance

The effects depend on dosage, duration of use, and individual factors.

Medical treatment and doping – not the same thing

It is important to distinguish between doping and medical treatment. Testosterone is used in healthcare when there is a confirmed testosterone deficiency , a condition characterized by both clear symptoms and repeatedly low levels in the blood.

At the same time, research shows that many individuals treated with testosterone have normal levels to begin with, raising concerns about overuse.

A growing gray area

The use of testosterone today exists in a growing gray area between medical treatment and performance enhancement. Interest in the hormone has increased, particularly in connection with symptoms such as fatigue, reduced sex drive, and low energy. However, these symptoms can have many causes and are not always due to low testosterone.

Testosterone and doping in Sweden – what happens in the body?