What is testosterone?
Testosterone is a steroid hormone produced in the testes (men), ovaries (women), and adrenal glands. It supports muscle mass, bone density, sex drive and red blood cell production.
Key Effects
- •Body — muscle, bone, fat distribution, red blood cells
- •Sexual health — sex drive, sperm production
- •Behaviour — small, context-dependent links to competition and status; weak links to aggression
Why does testosterone matter?
Testosterone matters because it shapes male sexual development and helps maintain health in adults of all sexes. Before birth and at puberty it drives the development of male reproductive organs, a deeper voice, and body and facial hair, and it supports sperm production.
It also stimulates red blood cell production, and part of it is converted in tissues to estradiol, which is important for bone health in men. Women produce much smaller amounts, and their levels are tied to ovarian and adrenal function. Popular links between testosterone and dominance or confidence are more complicated in research than they sound, and findings in people are mixed.
What affects testosterone?
Age, sleep, body weight, illness, and certain medications are among the main influences on testosterone. In men, levels usually peak in early adulthood and decline slowly with age. Levels also follow a daily rhythm, typically highest in the morning, which is why blood tests are often taken then.
Short or disrupted sleep, obesity, type 2 diabetes, and serious illness are associated with lower levels. Opioids and anabolic steroids can suppress the body's own production. Low testosterone, or unusually high levels in women, should be evaluated by a doctor.
In ONDA Life
Part 5 of the ONDA practice path, "I Guard the Territory", uses posture, breathing and attention practices aimed at steady, calm presence. ONDA does not measure testosterone, and there is no evidence that these practices raise it.