Testosterone

Testosterone is a steroid hormone (androgen) made by the testes in males. Its production is stimulated and controlled by luteinising hormone (LH), which is manufactured in the pituitary gland. In males, testosterone stimulates development of secondary sex characteristics, including enlargement of the penis, growth of body hair and muscle, and a deepening voice. It is present in large amounts in males during puberty and in adult males to regulate the sex drive and maintain muscle mass. Testosterone is also produced by the adrenal glands in both males and females and, in small amounts, by the ovaries in females. In women, testosterone is converted to oestradiol, the main sex hormone in females.

A blood sample is taken by needle from a vein in the arm.

No test preparation is needed.