Testosterone is a vital male sex hormone, also present in women in smaller amounts, crucial for various bodily functions. In men, testosterone plays a key role in the development of male reproductive tissues, including the testes and prostate, and promotes secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. It also influences libido, mood, and energy levels. In women, testosterone contributes to ovarian function, bone strength, and sexual desire.
Total testosterone represents the sum of both free testosterone and testosterone bound to proteins in the blood, such as sex hormone-binding globulin (SHBG) and albumin. Measuring total testosterone levels provides an overall assessment of the body's testosterone production.
Low testosterone levels in men, known as hypogonadism, can lead to a range of symptoms and health issues. These can include reduced libido, erectile dysfunction, decreased muscle mass and strength, increased body fat, decreased bone density (osteoporosis), low energy levels, fatigue, depression, and impaired cognitive function. Causes of low testosterone include aging, obesity, certain chronic diseases, and specific medical treatments. In women, low testosterone levels can result in diminished libido, fatigue, and a decrease in well-being.
Conversely, excessively high testosterone levels can cause problems as well. In men, it might be due to anabolic steroid use or testosterone supplementation, leading to aggressive behavior, acne, increased risk of heart disease, liver disease, and decreased sperm production. In women, high testosterone levels can indicate conditions like polycystic ovary syndrome (PCOS), manifesting in symptoms such as irregular menstrual cycles, excess hair growth, and obesity. Balancing testosterone levels through lifestyle changes, medication, or treating the underlying cause is crucial for overall health and well-being.
To maintain healthy testosterone levels:
Engage in regular exercise, particularly resistance training, as it can help boost testosterone levels naturally.
Maintain a healthy weight, as obesity can contribute to lower testosterone levels.
Ensure a balanced diet rich in protein, healthy fats, and complex carbohydrates, as these nutrients are essential for hormone production and overall health.
Total Testosterone can be measured in: ng/100mL, ng/dL, ng/L, ng%, nmol/L, µg/L
Reference ranges represent typical values for healthy individuals. Your healthcare provider must interpret your specific results.
| Age Range | Gender | Unit | Optimal | Normal | Source |
|---|---|---|---|---|---|
| All ages | Woman | ng/dL | - | 7.1 - 49.8 | Botelho, 2011 |
| All ages | Man | ng/dL | - | 264 - 916 | Bhasin, 2017 |
Testosterone is a key hormone influencing muscle mass and strength. It promotes muscle growth by stimulating protein synthesis and inhibiting protein breakdown in muscle cells. Testosterone also plays a role in muscle repair and recovery after exercise. Hormonal imbalances, such as low testosterone levels, can lead to decreased muscle mass, strength, and overall muscle function. [Sinha-Hikim, 2003][Herbst, 2004]
In men, low testosterone levels have been linked to poor sleep quality, reduced REM sleep, and sleep disturbances. At the same time, sleep deprivation leads to significant testosterone decline. Testosterone levels fluctuate throughout the day.[Wittert, 2014][Leproult, 2011]
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High cortisol is under certain conditions associated with lowers levels of testosterone. [Brownlee, 2005][Cumming, 1983].
In men, testosterone is the primary precursor for estradiol production via the action of the enzyme aromatase. The balance between testosterone and estradiol is crucial for maintaining various physiological functions, including reproductive health, bone density, and cardiovascular health. Elevated estradiol levels in men can lead to symptoms such as gynecomastia (breast tissue growth), while low levels can affect bone health and libido.[Schulster, 2016]
Total testosterone represents the sum of both free testosterone and testosterone bound to proteins in the blood, such as sex hormone-binding globulin (SHBG) and albumin. Measuring total testosterone levels provides an overall assessment of the body's testosterone production. Measuring free testosterone levels can provide a more accurate assessment of the hormone's activity in the body, as it represents the readily available portion of testosterone.
DHEAS serves as a key testosterone precursor in both sexes. In men, it contributes to total androgenic activity, becoming more important as testicular production naturally declines with age. In women, DHEAS conversion significantly contributes to testosterone levels, particularly post-menopause. In men, this contribution is smaller, but relevant especially in the elderly.[Labrie, 2001]
In men, FSH acts on Sertoli cells to support sperm development, while LH-driven testosterone completes maturation. Proper sperm production requires both hormones working in concert.[Iliadou, 2015]
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