What causes low testosterone?


Also: obesity, diabetes, diet, and substance abuse

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Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

Common causes of low testosterone

Low testosterone is when a man’s testosterone levels stay below 300 ng/dL. One of the main causes of low testosterone is hypogonadism—a condition in which the testicles either don’t make enough testosterone or they don’t receive the proper signals from the brain to make testosterone. Other causes of low testosterone (low T) include:

  • Diabetes
  • Obesity
  • Poor diet
  • Alcohol abuse

Obesity is a major contributor to low T, partly because fat cells can turn testosterone into estrogen and because of a reduction in sex hormone-binding globulin (SHBG).

Testosterone levels in men change

If your testosterone levels are low, don’t panic. Testosterone levels in men decline by about 1% every year after peaking in their 20s. That’s why low testosterone is more common for men in their 50s and 60s. Your testosterone levels also change constantly throughout the day.

Men typically have more testosterone in the morning than at night. So make sure you get tested in the morning and talk to your doctor about how your testosterone levels compare to normal levels relative to your age, lifestyle, habits, and other health risks. Everyone is different.

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