Testosterone and Oestradiol Blood Test, from our experts to you.
Dr Sam Rodgers MBBS, MRCGPChief Medical Officer

What is testosterone and what does it do?
Testosterone is a male sex hormone produced by the testes in men's and women's ovaries and adrenal glands - but usually in smaller quantities. It governs many essential functions, such as sex drive (libido), energy levels, healthy bones, muscle mass, strength, and mood. In men, it also controls sperm production, so your levels can affect your fertility. Elevated testosterone in women can cause male characteristics, such as excessive hair, and is commonly associated with polycystic ovary syndrome. Heavy alcohol consumption, liver disease, and AAS (anabolic androgenic steroids) can reduce testosterone levels. Women taking oestrogen therapy may see increased testosterone levels.
What is oestradiol and what does it do?
Oestradiol is a female steroid hormone produced in women's ovaries and, to a much lesser extent, in men's testes. It accounts for 80% of the oestrogen in the female body and is responsible for developing and maintaining the reproductive system, including fat distribution, preparing the follicles in the ovary for the release of an egg, and helping maintain bone density.
Men naturally convert some testosterone to oestradiol, and it's important for bone mass and sexual function. However, sometimes men can produce too much oestradiol compared with testosterone. This can result in female characteristics, especially the form of breast tissue (gynecomastia, moobs, or man-boobs).
What can I learn from a Testosterone and Oestradiol Blood Test?
Our Testosterone and Oestradiol Blood Test can tell you your balance of testosterone and oestradiol. If you're a man, it can help you investigate symptoms of low testosterone and symptoms of high oestradiol (such as man-boobs) and check your hormones if you're taking testosterone replacement therapy (TRT). For women, this test can help investigate symptoms of high testosterone (such as excessive hair) and polycystic ovary syndrome.
What's Included?
How to prepare for your test
Special Instructions
Prepare for your Testosterone and Oestradiol Blood Test by following these instructions. Please take your sample before 10am. Take this test two to five days after the start of your period, ideally on day three. It can be taken any time if you do not have periods. Hormonal contraception can affect this test, taking a break from this and using barrier contraception will give more accurate results. If you use hormone gels, pessaries, patches, or tablets, we strongly recommend selecting a venous sample to minimise contamination sometimes seen with finger-prick tests. Otherwise, administer any hormone supplements using gloves, and make sure your fingers have not been in contact with hormone supplements for at least four weeks before taking the test. Hormones can be absorbed deep within the skin even after minimal contact and remain there for weeks despite vigorous handwashing. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.