This blood test checks for unusual levels of testosterone and oestradiol, which may affect sexual libido, erectile function and fertility in men and ‘male characteristics’ in women such as excessive hair or help to explain abnormal periods, heavy bleeding or symptoms of menopause. Oestradiol is a steroid hormone and accounts for 80% of the oestrogen in women. It is secreted by the ovaries and is responsible for the development and maintenance of reproductive structures, including fat distribution, preparing the follicle in the ovary for the release of an egg, getting ready for fertility and helping to maintain bone density. In men, high levels of oestradiol can cause the development of breast tissue (gynaecomastia or man boobs) and affect sexual function. Our Testosterone, Free Testosterone and Oestradiol Blood Test measures your total and calculated free testosterone, oestradiol, and SHBG level. With it, you can check for unusual levels of testosterone and oestradiol, which may affect sexual libido, erectile function, and fertility in men and male characteristics in women, such as excessive hair, or help to explain abnormal periods, heavy bleeding, or symptoms of menopause. Prepare for your test 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. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.