Men and women both produce testosterone, though men produce far more testosterone than women. Testosterone levels can vary greatly depending on someone's gender, age and health. Find out more about low testosterone levels, and possible causes and symptoms of low testosterone.
What is testosterone?
Testosterone is the main sex hormone produced by men and is important in the development of the testicles and penis at puberty, as well as producing ‘male characteristics’ of the body, such as facial and body hair.
In men, testosterone carries out important body functions, including regulating sex drive and helping the testes make sperm. In women, testosterone is mainly converted to a form of oestrogen.
What is a normal testosterone level?
Men produce a lot more testosterone than women.
A pregnant woman will have 3-4 times more testosterone than a healthy, non-pregnant woman.
Testosterone levels are usually highest between the ages of 20 and 30. From the age of 30, they gradually reduce in most men.
What causes low testosterone levels?
Low testosterone levels can be caused by:
- medical problems such as severe liver disease
- damage to the testicles or the pituitary gland
- genetic disorders such as Klinefelter syndrome
Older men can have low testosterone levels. If this is a problem, you may want to speak to your doctor about whether this is due simply to getting older, or if it’s caused by something else.
Low testosterone symptoms
Men with low testosterone levels in men might have:
- reduced libido, problems getting and keeping erections and infertility
- changes in sleep patterns and poor sleep
- physical changes such as:
- increased body fat
- reduced muscle bulk and strength
- decreased bone density
- swollen or tender breasts
- hot flushes and sweats
- body hair loss
- lower energy levels
- emotional changes, such as:
- decreased motivation or self-confidence
- mood swings
- difficulty concentrating or remembering things
Children with low testosterone levels might have a small penis and/or testes. They might have late puberty, poor growth, and they might now grow hair or their voice might not break.
Women with low testosterone levels might have:
- tiredness and lack of motivation
- loss of libido
How are testosterone levels tested?
The only way to check for low testosterone levels is by having 2 blood tests. Testosterone levels vary over the day, so if you have a low level on one blood test, you should have a discussion with your doctor before deciding what next steps to take.
Low testosterone treatment
Testosterone therapy, given by injections, gels, lotions, creams, patches or tablets, is used to treat low testosterone. It's unclear whether testosterone therapy has any benefit for older men who are otherwise healthy, and testosterone therapy may even be harmful in some situations.
The risks of testosterone therapy include:
- acne or other skin reactions
- weight gain
- non-cancerous growth of the prostate and growth of any existing prostate cancer
Getting diabetes or other illnesses under control and losing weight can also improve testosterone levels.
For more information about male reproductive and sexual health, visit Healthy Male
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Last reviewed: May 2020