Testosterone is the most important sex hormone in men, and key to healthy sexual functioning. It plays an important part in the development of the male reproductive system such as the testes, penis and prostate, apart from promoting secondary male characteristics such as increased muscle and bone mass, and body hair growth.
Testosterone also plays a role in men’s general health and wellbeing, which includes moods, behavior, blood and bone health. In men, testosterone is secreted primarily by the testicles. Levels of testosterone in men are about eight times higher than in women.
Low testosterone levels in men have been linked to issues like irritability, depression, lower self-confidence, fatigue, lower sperm count, lower red blood cell production, weight gain, muscle loss, low sex drive (low libido), hair loss, and erectile dysfunction.
Testosterone levels decrease naturally as men get older, although it can also be the consequence of a disease called hypogonadism, the latter obstructing the ability to produce normal amounts of testosterone. Nevertheless, there are also other factors that can lead to lower levels, for instance lifestyle patterns such as excessive use of alcohol, coffee and certain drugs.
Mind that, apart from testosterone, the testes also produce other hormones, which include:
- Inhibin B — related to testicular volume and sperm counts in adults;
- Anti-Müllerian hormone — important for the development of internal male reproductive organs;
- Insulin-like factor 3 — helps testicles descend into the scrotum from the abdomen and to continue to develop in the scrotum;
- Estradiol (a type of Estrogen) — important in making sperm.