From the Guidelines
Normal testosterone levels in adult males typically range from 300 to 1,000 nanograms per deciliter (ng/dL) of blood. These levels can vary throughout the day, with highest concentrations usually occurring in the morning, which is why testosterone testing is often recommended in the early morning hours, as suggested by the American Urological Association (AUA) guideline on erectile dysfunction 1. Testosterone levels naturally decline with age, decreasing approximately 1-2% per year after age 30. Several factors can influence testosterone levels including obesity, chronic illness, medications, alcohol consumption, and stress.
Key Factors Influencing Testosterone Levels
- Obesity
- Chronic illness
- Medications
- Alcohol consumption
- Stress Low testosterone (hypogonadism) may cause symptoms like decreased libido, erectile dysfunction, fatigue, reduced muscle mass, and mood changes. According to the AUA guideline, serum total testosterone should be measured in all men with erectile dysfunction to determine if testosterone deficiency (TD), defined as total testosterone <300 ng/dL with the presence of symptoms and signs, is present 1. High testosterone is less common but may result from certain medical conditions or testosterone supplementation. Regular health check-ups can monitor testosterone levels, and if abnormalities are detected, further evaluation by a healthcare provider is recommended to determine appropriate management.
From the Research
Normal Testosterone Levels in Adult Males
- Normal testosterone levels in adult males are not explicitly defined in the provided studies, but the effects of testosterone replacement therapy (TRT) on obstructive sleep apnea (OSA) and hypogonadism are discussed 2, 3, 4, 5, 6.
Relationship Between Testosterone and Obstructive Sleep Apnea
- Studies suggest that OSA is associated with decreased testosterone secretion, and TRT may alleviate erectile/sexual dysfunction, but may also exacerbate OSA in some patients 3, 4, 5, 6.
Effects of Testosterone Replacement Therapy
- TRT has been shown to worsen sleep-disordered breathing in men with OSA, particularly at high doses, but the effects of lower doses over the longer term are less clear 3, 4.
- Some studies suggest that TRT may improve hypogonadism and erectile/sexual dysfunction in men with OSA, but patients should be monitored for OSA symptoms before and after starting TRT 5, 6.