What Causes Low Testosterone?

Clinicians group low testosterone into two broad categories based on where the problem lies. In primary hypogonadism, the testes themselves are not producing enough testosterone despite normal or high signals from the brain. In secondary hypogonadism, the testes are capable, but the pituitary gland or hypothalamus is not sending strong enough signals to drive production.

This distinction is more than academic. It shapes what tests come next, whether an underlying condition needs treating, and which options make sense - especially for men who want to preserve fertility, as discussed in TRT and fertility.

Several everyday factors can lower testosterone, and some are at least partly reversible:

• Excess body weight, particularly abdominal fat, is strongly associated with lower testosterone
• Poor or insufficient sleep, including untreated sleep apnea
• Chronic stress and its effect on the hormonal axis
• Heavy alcohol use
• A very sedentary routine or, at the opposite extreme, extreme overtraining and under-eating

Because these can suppress levels, a thoughtful clinician may address them first. Our guide to natural ways to boost testosterone covers the evidence-based lifestyle levers.

A range of health conditions can drive testosterone down. These include type 2 diabetes and metabolic syndrome, chronic kidney or liver disease, HIV, and disorders of the pituitary gland such as a benign tumor raising prolactin. Genetic conditions like Klinefelter syndrome affect the testes directly.

Medications matter too. Long-term opioids, some steroids, and certain other drugs can suppress testosterone. Prior chemotherapy, radiation or testicular injury can also reduce production. This is why a clinician reviews your full medical and medication history rather than looking at one lab value in isolation.

Testosterone tends to decline slowly with age, often from a man's thirties onward. For many men this decline is modest and stays within the normal range. When it dips low enough to cause symptoms, some clinicians describe it as age-related or late-onset hypogonadism. Age alone is not an automatic reason to treat - the level and symptoms still guide the decision, and other causes should be ruled out first.

Identifying the cause can change everything. If low testosterone is driven by obesity, sleep apnea or a medication, addressing that root issue may raise levels without lifelong therapy. If a pituitary problem is behind it, that condition needs its own management. And if a man wants to father children, the cause and the chosen approach both matter, because standard TRT can suppress fertility.

Good telehealth providers build this workup into their process. You can see how they compare on our TRT clinic comparison and in our detailed provider reviews.

This article is general information, not medical advice. A licensed clinician should evaluate your symptoms and testosterone levels and decide whether TRT is appropriate for you.