Reproductive hormones
FSH
A pituitary hormone that tells the ovaries or testes to do their work. In women it moves through the menstrual cycle.
LH
A pituitary hormone that triggers ovulation in women and signals the testes to make testosterone in men.
SHBG
The protein that binds testosterone and oestrogen in the blood and decides how much is left free. It moves with thyroid hormone, insulin and the contraceptive pill.
Total testosterone
The main androgen circulating in your blood, most of it carried bound to proteins. It peaks in the early morning and falls through the day.
Free androgen index (calculated)
The ratio of your total testosterone to SHBG, used as a rough read of how much androgen is left unbound.
