An overview of the gonads (testes, ovaries, and sex hormones) From puberty to menopause, learn how these hormones affect libido, fertility and mood. Read More What are the parathyroid glands? Learn about the hormones that can affect your metabolism and overall wellbeing. Read More Everything you need to know about the endocrine glands From diabetes, your sleep-wake cycle to your immune function, these endocrine glands are vital to long-term health. Read More 1 2