History
In 1849 Germany's Arnold Berthold re-implanted testes into castrated roosters and saw their combs and crowing return, concluding that the testes release something into the blood. In 1889 France's Charles-Édouard Brown-Séquard, aged 72, injected himself with animal testicular extract and claimed rejuvenation, almost certainly a placebo effect. In 1935 Ernst Laqueur's Dutch team isolated crystalline hormone from bull testes and named it testosterone, and that same year Adolf Butenandt and Leopold Ružička independently synthesized it, sharing the 1939 Nobel Prize in Chemistry.
What it does
Testosterone drives puberty's deeper voice, facial hair and muscle and bone growth, and in adults it maintains muscle mass, bone density, libido, red blood cell production and motivation. It boosts skin oil, linking it to acne, and when converted to DHT in hair follicles it causes male-pattern baldness. Women make about a tenth to a twentieth as much in the ovaries and adrenals, using it for libido and muscle, and some is converted to estrogen. Men's levels fall about 1% a year after their 30s; fatigue, low libido, muscle loss and low mood together may point to late-onset hypogonadism, sometimes called male menopause.
Therapy and lifestyle
When blood levels are repeatedly low and symptoms are present, doctors may consider testosterone injections or gels. In the 2016 US Testosterone Trials, sexual function and mood improved somewhat, but the effects were modest. Side effects include excess red blood cells, worsening sleep apnea and infertility, so prescribing it to symptom-free men "for energy" isn't recommended. Strength training, seven or more hours of sleep and losing belly fat help keep levels up, while chronically high cortisol from stress can lower them. With age, exercise also guards against sarcopenia and osteoporosis.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
FAQ
- Are there foods that raise testosterone?
- Oysters and beef (zinc), eggs and oily fish (vitamin D) help prevent deficiency, but no single food raises normal levels much. Exercise, sleep and weight control matter more.
- When should testosterone be tested?
- Levels peak in the morning, so it's usually measured fasting between about 7 and 11 a.m., and a low result is rechecked on another day.
Sources reviewed: 2026-10-26
References
- David, K., Dingemanse, E., Freud, J., & Laqueur, E. (1935). Über krystallinisches männliches Hormon aus Hoden (Testosteron). Hoppe-Seyler's Zeitschrift für physiologische Chemie, 233, 281–283.
- Bhasin, S., et al. (2018). Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. JCEM, 103(5), 1715–1744.
- Snyder, P. J., et al. (2016). Effects of testosterone treatment in older men. NEJM, 374(7), 611–624.