Overview
Testosterone is the most important male sex hormone. It influences muscle, bone density, blood formation, metabolism, mood and sexual function. Doctors speak of testosterone deficiency (hypogonadism) when repeatedly low blood testosterone levels are measured together with matching complaints – such as lack of drive, loss of libido or erectile dysfunction. From middle age onwards testosterone levels decline slowly; however, a deficiency requiring treatment is not a normal sign of ageing but a diagnosis in its own right. The work-up is laboratory-based: at least two morning blood samples on different days are decisive, because testosterone levels fluctuate considerably during the day. In a video consultation your complaints can be assessed in a structured way, suitable laboratory tests can be arranged and the results discussed in detail. Subject to medical assessment, treatment can then be initiated and supervised – from targeted lifestyle measures to testosterone replacement therapy with regular follow-up monitoring. Any necessary physical examinations are arranged in person where required.
Common causes
Testosterone deficiency can have many causes. The most frequent is so-called functional hypogonadism: obesity, type 2 diabetes, metabolic syndrome, chronic sleep deprivation or untreated sleep apnoea suppress the body's own testosterone production. Chronic illnesses, pronounced stress, regular alcohol consumption and certain medications – such as opioids or corticosteroid preparations – can also lower hormone levels. Less commonly the cause lies directly in the testicles (primary hypogonadism), for example after injuries, infections or chemotherapy, or in genetic conditions such as Klinefelter syndrome. In secondary hypogonadism the hormonal control by the pituitary gland or hypothalamus is disturbed, for instance by benign tumours or an elevated prolactin level. Previous use of anabolic steroids is also a relevant and often overlooked cause. The distinction is made using laboratory values such as LH, FSH and prolactin and determines the further diagnostic and therapeutic approach.
When to see a doctor
Seek medical evaluation if complaints such as persistent exhaustion, loss of libido, erectile dysfunction, unintended muscle loss or low mood persist for several weeks and affect your daily life. Early laboratory diagnostics prevent unspecific symptoms from remaining unrecognised for years or being treated prematurely without a confirmed diagnosis. Specific warning signs that should be examined promptly – preferably in person – include: palpable lumps, hardening or swelling of the testicles, newly developed breast tissue growth, new visual disturbances or unusually severe headaches, and an unfulfilled wish to have children. A structured work-up is also advisable if you have used anabolic steroids in the past. If you notice signs of a medical emergency – such as sudden chest pain, shortness of breath, paralysis, speech disturbances or impaired consciousness, as can occur with a heart attack or stroke – call the emergency number 112 immediately.