Welcome to GreenEyedGuide, your guide to the science behind caffeine and energy drinks. This is a series on How Caffeine Affects the Brain. Since this is a complex topic and we have a lot to cover, I’ve broken the key questions into different posts. In Part 1 we’ll discuss how caffeine makes you feel awake and alert, we’ll review the biochemistry (which you can skip), and we’ll summarize the ways caffeine does and does not help you focus.
Later in this series, we’ll also talk about:
- Why does caffeine work differently after an all-nighter?
- What ingredients in energy drinks help you focus during gaming?
- Is coffee or energy drinks better for studying?
- Does your brain get addicted to caffeine and energy drinks?
Part 1: How does caffeine help you focus?
- It’s easier to pay attention when you’re not sleepy – caffeine makes you more alert by blocking a molecule named adenosine
- When adenosine sits on its throne (a receptor in the brain), it sends signals to tell you to sleep
- When caffeine blocks adenosine, adenosine cannot tell you to sleep

Being awake is not the same as being alert.
Being awake is not the same as being alert, just like hearing is not the same as listening.
In a previous post, we reviewed a Nootropic drink called Focus Aid and used a Harry Potter reference to explain how caffeine helps you focus. Here are the highlights:
Caffeine Boosts Dopamine
- Caffeine stimulates the nervous system, which has consequences all over the body
- All sources and forms of caffeine help you focus because caffeine enhances dopamine signaling in the brain
- Dopamine is a neurotransmitter, a chemical that sends signals/messages to nerve cells
If adenosine is Vernon Dursley, dopamine is an owl, and dopamine’s signal is a letter. When caffeine blocks adenosine, adenosine can’t block dopamine, which means LOTS OF MESSAGES get through!!!

What Caffeine Can and Can’t Do for Your Brain
There are limits to caffeine’s powers, according to research by Bichler, Swenson, and Harris [2006, Amino Acids]. Caffeine stimulates the nervous system; it doesn’t help you with mathematical reasoning, logic, or short-term memory. Caffeine provides a boost of energy to do routine maneuvers but makes it harder for a person to patiently tackle

The Science Behind Caffeine and Cognition
If you’re not into biochemistry, feel free to skip this paragraph!
- When adenosine is docked in A1, it suppresses the signal from dopamine because the adenosine receptor and the dopamine receptor are G-coupled proteins
- Binding caffeine to adenosine receptor A1 leads to inhibition of the adenosine signal
- By inhibiting adenosine, caffeine removes that suppression, which enables dopamine signaling
- Dopamine signaling activates adenylyl cyclase which increases levels of cAMP
- Increased cAMP increases PKA
- Increased PKA leads to increased locomotor activity, which is observed as caffeine’s stimulatory effects
Stay tuned for the next part of the series: is coffee or energy drinks better for studying?
Caffeine is good at helping you focus, but do the other ingredients in coffee help or hinder? How well do theanine and caffeine get along? What about caffeine and taurine? Stay tuned for Part 2!
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