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How caffeine works… in plain english

Caffeine chemical molecule structure.
For the purposes of this article, brain cell = neuron = nerve cell.
The ancient drink also known as coffee has been around for centuries, with the earliest records of it found around 10th century Ethiopia. Its resilience as a popular drink is remarkable as many of us still drink it on a near daily basis till this very day, centuries after it was first discovered. It is worth considering why coffee has stuck around for so long and is loved by so many. After all, coffee doesn’t get you happy drunk like alcohol will, and strictly avoiding it won’t kill you like strictly avoiding water probably will. So why do many of us still drink this brownish black liquid so often? Well, with the right mixture of sweeteners and cream dialed in to suit each individual’s taste, it actually tastes pretty good. Also, it can give you an energy jolt of biblical proportions when you need to get something done.

I think you know the feeling. Perhaps you have a term paper due or a midterm you absolutely have to ace or an important presentation at work or maybe a couple of songs to learn for your next musical gig, but you are dead tired with very little natural energy left. The most natural way to cure your tiredness – sleep – is out of the question because you need time to prepare for your upcoming shindig to avoid embarrassing yourself. Hmmm… what do you do to keep yourself alert/awake? Well I don’t know about you guys, but I personally reach for the nearest ~12 ounce cup of warm coffee that I can find and chug it.

Why does caffeine keep you alert?

As a child I always wondered why coffee had that special ability to keep people awake? Years later as a teenager, I found out that it is the caffeine in coffee that keeps us awake. While that is true, it begs the question as to why caffeine has that magical power. If you’re interested in looking deeper as we frequently do here on the blog, keep reading.

Caffeine is a naturally occurring stimulant with the chemical formula – C8H10N4O2. In plain english, saying that caffeine has the chemical formula C8H10N4O2 means that each molecule of caffeine contains 8 carbon (C) atoms, 10 hydrogen (H) atoms, 4 nitrogen (N) atoms, and 2 oxygen (O) atoms. If you are ever in and around hardcore scientific circles, you may also hear caffeine referred to by its technical name – trimethylxanthine. In its pure form, caffeine is a super bitter white powder that bears a certain resemblance to cocaine. As most of you know, caffeine occurs naturally in coffee, some tea leaves, and for my fellow Nigerians reading this, the much revered Kola nuts that we use during many marriage ceremonies also contain caffeine.

Caffeine has the effect of improving human alertness because it alters some of the brain chemistry that facilitates sleep. First of all, sleep is a weird thing if you think carefully about it from an evolutionary perspective. It doesn’t seem very advantageous on the surface for you or I to be unconscious for roughly a third of our lives. The need for sleep is especially strange when you consider the fact that back in the dark ages, there were critters lurking around every corner who would have loved nothing more than to turn a human into lunch or supper. So for evolution to mostly leave us alone with our need for sleep, it must be really really important for maintaining health and bodily function. Anyhow, I digress… let’s get back to discussing the brain chemistry of sleep. When either of us get tired, a chemical called adenosine is created in the brain. Adenosine binds to specific receptors on our brain cells (also called neurons or nerve cells), causing them to send electrical impulses much less frequently than they do when we’re awake and alert. This gradual slowing of electrical activity in the brain eventually causes us to fall asleep. In addition, the release of adenosine results in the dilation of blood vessels and some have theorized that the reason for this is to get more oxygen into the brain during sleep to help rejuvenate it.

Depending on your point of view, caffeine is like the evil or awesome twin of adenosine and acts to block its activity in regards to the causation of sleep. The chemical structures of caffeine and adenosine are similar enough to trick nerve cells into thinking that both are the same thing. So when you drink a cup of coffee, the caffeine in it makes it to the brain and shoves adenosine out of the way, binding to the same cell receptors that adenosine would have otherwise bound to. When caffeine binds to these nerve cell receptors, it speeds up their electrical activity… resulting in the opposite effect that adenosine has on them. The master of your bodily hormones – the pituitary gland – which sits at the base of your brain, sees this increase in nerve cell activity as an indicator that you are in some sort of trouble, and instructs the adrenal glands to produce epinephrine which you may also know as adrenaline. The surge of adrenaline makes your pupils dilate, speeds up your heart rate, increases your blood pressure, and causes your liver to release sugar into your bloodstream. All of the above results in a nice caffeine induced buzz that you have probably experienced at some point in your life.

The structures of Caffeine and Adenosine. Notice how similar their central ring structures (highlighted in light blue) are. This similarity is why Caffeine can trick the receptors on the neurons into "thinking" that it is adenosine.
The structures of Caffeine and Adenosine. Notice how similar their central ring structures (highlighted in light blue) are. This similarity is why Caffeine can trick the receptors on the neurons into “thinking” that it is adenosine.

Caffeine and addiction

I won’t name names, but I have a few dear friends that I am pretty sure are addicted to caffeine. Truth be told, that was me in college… practically incoherent each morning until my first cup of coffee. Here’s why caffeine can be addictive.

Dopamine is the “feel good” chemical that activates the pleasure centers in certain parts of your brain. Hard drugs like heroin and cocaine manipulate dopamine levels in the brain by slowing down the rate at which dopamine is cleared out which has the net effect of keeping the feeling of pleasure around for longer periods. Funny enough, caffeine manipulates dopamine levels in much the same way as cocaine and heroin… it’s just that its effect is a lot weaker than those dangerous drugs.
In conclusion, caffeine works by blocking adenosine activity in your brain and speeding up your brain cells which makes you feel alert. The resultant increase in the activity of the brain cells causes the adrenal glands to produce adrenaline which gives you a buzz. Caffeine also effectively works to increase dopamine (also known as the “feel good chemical”) levels in your system to make you feel good. Like many other things in life, coffee in moderation is perfectly fine and probably won’t harm you. If you go overboard though, you’ll effectively put your body on perpetual high alert mode. You see the human body is designed to actually grow from relatively short bursts of stress… this is one of the main reasons why weightlifting works so well for growing muscular mass. However, the human body will break down if it is constantly subjected to the stress related chemistry that near constant jolts of caffeine will eventually create. From all of us here at, please take care of yourselves and each other.
Without Wax
Oyolu B.C. Ph.D.
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