What Does Caffeine Do to Your Brain?
Posted on Dec 07, 2016

As a medical professional, I’m often asked about caffeine and its effects on the brain. Caffeine is one of the most widely consumed psychoactive substances in the world, with millions of people drinking coffee, tea, and energy drinks every day. In this blog, I’ll explain a bit of what caffeine does to the brain, both the positive and negative effects.  


Caffeine has a number of positive effects on the brain. The most well-known effect is that it can increase alertness and help people feel more awake. This is because caffeine is a central nervous system stimulant that can block the effects of adenosine, a chemical in the brain that can make you feel sleepy.

Caffeine can also improve cognitive function. Studies have shown that caffeine can improve attention, reaction time, and memory. It’s believed that caffeine does this by increasing the production of certain neurotransmitters, such as dopamine and norepinephrine, which are involved in cognitive function.

In addition to these cognitive benefits, caffeine has also been shown to have some protective effects on the brain. Studies have suggested that caffeine may help protect against neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. While the exact mechanisms behind this protection are not yet fully understood, it’s believed that caffeine may help reduce inflammation and oxidative stress in the brain. That said, most nutrition-focused studies are difficult to do well.


While caffeine has a number of positive effects on the brain, it’s important to note that it also has some negative effects. One of the most common negative effects of caffeine is that it can cause anxiety and jitteriness in some people. This is because caffeine can increase the production of cortisol, a hormone that is associated with stress. Likewise, if one is sleep-deprived and then caffeine blocks the effects of the normal sleep pressure build up, by blocking adenosine receptors, irritability would seem inevitable.

Caffeine can also disrupt sleep. Studies have shown that consuming caffeine can make it harder to fall asleep and reduce the amount of deep sleep that people get. This can lead to feelings of fatigue and grogginess the next day. If you struggle with sleep, try to avoid stimulants like caffeine after noon or one o’clock.

Finally, it’s important to note that caffeine can be addictive. Regular consumption of caffeine can lead to physical dependence, and withdrawal symptoms can occur if people try to quit. These withdrawal symptoms can include headaches, fatigue, and irritability. Most research would suggest that the withdrawal is minor and tolerated by most people.


Overall, caffeine has a number of positive effects on the brain, including increased alertness and improved cognitive function. Additionally, caffeine may help protect against neurological disorders. However, it’s important to note that caffeine can also have some negative effects, such as anxiety, disrupted sleep, and addiction.

If you’re a regular consumer of caffeine, it’s important to be aware of both the potential benefits and harms of caffeine. If you find that caffeine is causing negative effects, such as anxiety or disrupted sleep, it may be helpful to reduce your consumption, or change the timing of that consumption. On the other hand, if you’re looking to improve your cognitive function or protect against neurological disorders, moderate caffeine consumption may be beneficial. As with any dietary decision, it’s important to talk to your healthcare provider before making any major changes.