The word hormone comes from the Greek word hormao, which means to stimulate and set-in motion – and that is exactly what hormones do. Hormones are chemical substances, molecules that act as messengers between the body’s cells. They carry instructions to other parts of the body, where they help control how cells and organs do their work. For example, it could be a message that a particular protein needs to be synthesized or broken-down.

Most people probably think about our sex hormones when they hear the word hormone, but the sex hormones represent only a small portion of the high number of hormones that are found in the body. Each hormone has a specific task in the body and it binds to a unique receptor on the cell’s surface – like a key fits perfectly into a lock. 

You have to use a certain key to be able to open the door and the hormones act like these keys. Once a hormone binds its receptor, the cell is "opened" and the hormone can deliver its message. If the "lock" is damaged, like it happens in insulin resistance, the door cannot be "opened" and the levels of that hormone will increase in the body, but without being able to perform its task inside the cell.

The release of hormones

Hormones are primarily formed in what we call the endocrine glands like the thyroid gland, the adrenal glands, the ovaries, the pancreas, the pituitary gland and the hypothalamus. All these glands control important physiological functions in the body such as bone formation, the immune system and biological transformations, such as the transition from the fertile phase to menopause.

The endocrine glands control the body’s functions by releasing hormones, which travel through the bloodstream to reach certain cells or organs. The brain is the one who has the control and decides which hormone gets released by the glands and when.

When the brain senses that the body has low levels of a certain hormone, it sends a message to the gland to produce that hormone, until the part of the brain called the hypothalamus understands that the level is normal and signals to the gland to stop the production until the levels are low again. The feedback mechanisms between the brain and hormones regulate our body’s balance. In this way hormones affect hundreds of biological processes in the body.

Hormone functions

Estrogen, testosterone and progesterone are called sex hormones and control, among other things, hair and muscle growth, menstruation and fertility. Insulin, TSH, cortisol, DHEA and melatonin influence physiological functions such as metabolism, mood swings and the ability to deal with stress. Fat cells are the largest endocrine gland in the body. Fat secretes hormones such as leptin, which regulates appetite and adiponectin, which regulates how you burn fat.