Sex Hormone Binding Globulin
This protein is produced by the liver, controlled by sex hormones, thyroid hormones, insulin, and dietary factors and binds to sex hormones – testosterone, DHT (dihydrotestosterone), and oestrogen (estradiol). It helps transport them in the blood. SHBG levels, which change with age, vary between men and women, and can help control the levels of androgens and oestrogens in the body. It can help to determine testosterone levels in the blood, since around 40-60% of total testosterone is bound to SHBG in men.