Understanding how caffeine works within our brains can be as easy as saying “it keeps me awake.” However, its specific mechanisms are much more interesting than that. In fact, it will take a series of explanations before we get to the point of explaining why it does it. So, before we continue with this, have a coffee and then read on.

Caffeine is the most accessible psychoactive substance that exists. Your kitchen cabinets and storage will prove it. Coming from the word psychoactive, it activates the psychological aspect of the human body or more popularly called the human mind. The process begins with the fact that when the liver metabolizes caffeine, it breaks down into three components.

These components are paraxanthine, theobromine and theophylline. Its effects are lipolysis (the breakdown of fatty acids), dilation of blood vessels leading to increased urine output, and relaxation of the smooth muscles of the bronchial tubes in the lungs.

The paraxanthine in caffeine is specifically responsible for increased alertness and insomnia. One of its effects or functions is to be a non-selective antagonist of the adenosine receptor. This means that it opposes the functions of the adenosine receptors, which is to bind to adenosine, the chemical responsible for why people fall asleep. Caffeine can do this because:

1. It can pass from the bloodstream directly to the brain (that’s what it means when medically inclined people say it can cross blood-brain barriers)

2. Its molecular structure is similar to adenosine. Instead of adenosine binding to adenosine receptors, caffeine has the ability to take its place.

Without the interference of caffeine, what normally happens is that once adenosine binds to adenosine receptors, it slows down metabolic processes in the brain. It does this by reducing the action of synapses (sort of cute storage spaces at the end of each nerve) from releasing chemicals that are responsible for impulses traveling from all over the body to the brain and back.

Having reduced the activity of chemicals to a lower rate (thanks to adenosine binding to adenosine receptors), almost all activities in the human body will soon return to a resting state and then eventually to sleep.

stop. Read the previous paragraph. Have you understood the role of adenosine and adenosine receptors in a person’s sleep cycle? If he did, then he must have come to a conclusion: Stopping adenosine receptor function is like canceling sleep itself.

Blocking their function prevents other chemicals (intended for the brain to respond consciously to impulses) from being released from synapses, so normal brain metabolism, activity, or processes remain intact. That’s what paraxanthine does to your adenosine receptors. And since paraxanthin is a metabolized product of caffeine, logically that’s what caffeine does to your mind. It just “keeps you awake”.