Cortisol and testosterone are both hormones produced by the adrenal glands, the glands that sit atop the kidneys in the human body (testosterone is also produced in the male testes and the female ovaries, with only a small amount actually produced in the adrenals). Both hormones are affected during times of stress. Cortisol is increased and released into the body during stress; testosterone is forcibly reduced in output. Generally, both levels return to normal once a stressor has passed, but if that doesn’t happen within a reasonable amount of time, then low testosterone levels continue, to the detriment of the body.
Cortisol, Other Hormones and Stress
When our body is faced with a threat of some sort, it perceives this as a stressor and releases hormones. For example, if we are going to need to defend ourselves physically, the adrenal-produced hormone norepinephrine is secreted. If we need to be able to move away quickly from danger, then epinephrine (another adrenal hormone and sometimes referred to as adrenaline) is secreted. And if we need use of our muscles and brain to think and respond to the stress at hand, then cortisol is released along with one of the other two.
Testosterone Level Reduced by Stress and Cortisol Increases
In order for our body to meet the demands of unexpected stress and overproduce the aforementioned three hormones, it has to turn off other important bodily functions temporarily. This allows it to use the energy from those activities to aid it in the crisis of the moment. One hormone turned off temporarily during this stress period is testosterone, thus putting a short-term halt to its important work in regard to human growth and reproduction.
Dangers of Low Testosterone Levels Due to Cortisol
If the stressor is not eliminated soon after the episodic event (for example, a person may not be able to leave the battlefield, or a child may not be able to flee abuse at home), then high cortisol levels continue to exist in the body, keeping other systems compromised--like those driven by testosterone (growth and reproduction). When the level of testosterone in the body is too low because the cortisol levels are too high, normal growth and reproduction processes are jeopardized.
Negative Effects of High Cortisol Levels on Testosterone
The halting of female ovulation and male sperm release are two effects of cortisol levels that are too high. But that isn't the only negative effect to testosterone due to continuing high levels of cortisol. Another is the halting of sex-hormone manufacturing by the body (testosterone, progesterone and estrogen), which can adversely affect sexual desire, menstruation, ejaculation, mood and other bodily functions dependent upon these needed hormones.
In addition, growth can be retarded, stature can become limited, and normal growing processes can be hindered (if the high stress level occurs during childhood or youth). In adults, especially those going through menopause, adverse effects can be felt due to an even greater decline of the sex hormones than normally experienced at this stage in life. Continued high levels of cortisol can eventually lead to depression.