Testosterone is a hormone that contributes to the most manly of bodily functions: sex drive, muscle strength, aggression, mood, and sperm production.
Testosterone levels naturally decline with age, but roughly 20% of men over the age of 60 have abnormally low levels of this vital hormone.
Low testosterone (also called “male hypogonadism”) is associated with a range of unpleasant symptoms including:
- Hair loss
- Weight gain
- Decreased sex drive
- Difficulty maintaining erection
- Decreased muscle mass
As if these symptoms weren’t bad enough, low T is also associated with depression.
Depression is a mental illness characterized by social isolation, over- or under-eating, fatigue, difficulty concentrating, loss of interest in activities previously enjoyed, and feelings of sadness and hopelessness – including thoughts of suicide.
Depression is far more prevalent than most people realize. According to the World Health Organization, depression is “the leading cause of ill health and disability worldwide.”
Research shows us that hypogonadal men who take testosterone supplements are less likely to suffer depression than men who avoid treatment.
T therapy works to improve mood by boosting the body’s production of serotonin (the “happy chemical”).
In 2015, Austrian researchers studying the effects of hormone therapy on transsexuals discovered that testosterone boosted the number of SERTs (proteins responsible for carrying serotonin to different parts of the brain).
Testosterone treatment in female-to-male patients increased SERT binding in several parts of the brain, while estrogen treatment in male-to-female patients produced the reverse effect.
These findings explain why testosterone therapy can boost mood and also why depression affects more women than men and more older men than younger men.
Furthermore, the study suggests testosterone therapy can boost the effects of antidepressants by improving the binding sites for those medications in the brain.
A separate study published in January 2019 found that higher doses of testosterone produced greater antidepressant effects.
“Testosterone treatment appears to be effective and efficacious in reducing depressive symptoms in men, particularly when higher-dosage regimens were applied in carefully selected samples,” wrote the authors.
The study, which included 27 trials and nearly 2,000 participants, found no relationship between antidepressant benefits and patients’ initial T levels. These findings contradict earlier studies, which suggested testosterone therapy for depression was most effective for patients with low T.