The Testosterone Blood Test

Testosterone is a sex hormone made by the testes in men and by the ovaries in women. It plays an important role in sex drive, fertility, mood and muscle mass.

Take your test in the morning between 7 a.m. and 10 a.m. This is when your testosterone levels are at their highest.

Conditions that affect your testes can cause your testosterone levels to drop, along with direct injury, infection or radiation.

Genetic conditions such as Klinefelter syndrome (when boys are born with an extra X chromosome) can also lower your testosterone levels.

Tumours, auto-immune conditions and some medications can trigger low testosterone too.

Low testosterone levels can affect fertility by causing a drop in your sperm production. They can also indirectly affect your fertility by lowering your sex drive and causing erectile dysfunction.

You generally don't need to do anything to prepare for a testosterone test.

However, sometimes you may need to stop taking medications that could affect your testosterone levels. Some medications that can artificially increase your testosterone levels include hormone therapies and steroids.

Do not stop taking any prescribed medications without speaking to your doctor first.

Signs and symptoms of low testosterone levels include:

• low sex drive
• increased breast size 
• less body hair 
• difficulty concentrating 
• low mood and depression 
• loss of muscle mass

Testosterone is a major sex hormone which has a crucial role in males. Some of testosterone's functions include: 

• maintaining muscular growth and strength 
• regulating sex drive
• producing sperm
• regulating bone density

Testosterone also plays a vital role in females. Small amounts of it are made in the ovaries and adrenal glands, and – when combined with oestrogen – it helps with bone health, menstrual health and sex drive.

Talk to your doctor before taking this test. Being pregnant can have a noticeable impact on your results, so make sure to check in with your GP first.