GLOSSARY

Testosterone is the most important androgen (male sex hormone). In men it is made mainly by the Leydig cells of the testis, and in women in much smaller amounts by the ovaries and adrenal glands. It is a steroid hormone made from cholesterol.

Normal Range

• Adult men: about 10–35 nmol/L (about 300–1,000 ng/dL).
• Women: usually below 2–3 nmol/L, about 15 times lower than in men.

Most testosterone in blood is bound to SHBG and albumin; only about 2 percent is free.

Main Effects

• Muscle: increased protein synthesis, fibre hypertrophy and activation of satellite cells.
• Bone: increased bone size and density (partly through conversion to oestradiol).
• Blood: increased erythropoietin and haemoglobin.
• Sexual characteristics: hair growth, a deep voice and libido.
• Metabolism: less visceral fat and better insulin sensitivity.

Scientific Note

The short-term rise in testosterone after a resistance session does