Caffeine is one of the most popular additives. We consume it daily in the form of coffee, teas or energy drinks. Its positive effects are the wakefulness effect, mental and physical performance enhancement and accelerated metabolism. Side effects are heart palpitations, nervousness, nausea and gastrointestinal problems. The maximum daily dose is 400mg (e.g. 5 Red Bull à 250ml) and the maximum single dose is 200mg (e.g. 3 espressi).
However, how does caffeine act in the brain? Caffeine works in the brain between the synapses. The synapses are the connection points between the nerve cells. This is where messenger exchange or communication takes place. Adenosine is a messenger substance that docks at the adenosine receptors and transmits fatigue signals. Messenger and receptor are like two pieces of a puzzle and normally only the respective messenger can attach to the corresponding receptor. Now the molecule caffeine comes into play. This looks similar to adenosine on a molecular level and that is why it can also attach to the adenosine receptors. Now the caffeine covers the adenosine receptors and the adenosine itself can no longer dock. Thus, no fatigue signals can be transmitted and one remains awake.