For lovers of coffee, you can usually tell what kind of day it’s going to be by the number of cups it takes to get you going.

One or two cups and you’re good to go? It’s all going to be sunshine and daisies for you today. Three or four cups? Whilst the love is there for your babies, so is an abundance of love for sleep and in its absence – coffee. More than four cups? Danger! DANGER!

Whilst any addiction isn’t pretty, those of us who find themselves short of their usual coffee fix will know this better than most.

Within 24 hours of going without, your withdrawal symptoms begin. Initially, they’re subtle: The first thing you notice is that you feel mentally foggy, and lack alertness. Your muscles are fatigued, even when you haven’t done anything strenuous, and you suspect that you’re more irritable than usual.

Over time, an unmistakable throbbing headache sets in, making it difficult to concentrate on anything. Eventually, as your body protests at having the drug taken away, you might even feel dull muscle pains, nausea and other flu-like symptoms.

This isn’t heroin, tobacco or even alcohol withdrawls. We’re talking about caffeine, a substance consumed so widely (with more than 80% of adults drinking it daily) that we often forget it’s a drug””and by far the world’s most popular psychoactive one.

Coffee, of course, is actually a superfood – filled with disease fighting antioxidants. But while a reasonable amount can provide some health benefits and boost focus and productivity; in excess, caffeine consumption could damage your health and prevent you from firing on all engines.

Over-consumption of caffeine can actually break your focus by causing jitters and anxiety, and lead to poor sleep. High caffeine consumption has also been linked with heightening the body’s stress response and with messing with your perception of your own stress levels.

Why, exactly, is caffeine so addictive?

The reason stems from the way the drug affects the human brain, producing the alert feeling that caffeine drinkers crave.

Structurally, caffeine closely resembles a molecule that’s naturally present in our brain, called adenosine. So closely, that caffeine can fit neatly into our brain cells’ receptors for adenosine, effectively blocking them off. Normally, the adenosine produced over time locks into these receptors and produces a feeling of tiredness.

When caffeine molecules are blocking those receptors, they prevent this from occurring, thereby generating a sense of alertness and energy for a few hours.

In people who are addicts of caffeine based drinks, the brain’s chemistry and physical characteristics actually change over time as a result. The most notable change is that brain cells grow more adenosine receptors, which is the brain’s attempt to maintain equilibrium in the face of a constant onslaught of caffeine. This explains why regular coffee drinkers build up a tolerance over time””because you have more adenosine receptors, it takes more caffeine to block a significant proportion of them and achieve the desired effect.

This also explains why suddenly giving up caffeine entirely can trigger a range of withdrawal effects. The good news is that, compared to many drug addictions, the effects are relatively short-term. To kick it, you only need to get through about 7-12 days of symptoms without drinking any caffeine. During that period, your brain will naturally decrease the number of adenosine receptors on each cell, responding to the sudden lack of caffeine ingestion.

If you can make it that long without a hit of caffeine, the levels of adenosine receptors in your brain reset to their baseline levels, and your addiction will be broken.