What does caffeine do?
Caffeine is a powerful stimulant, and it can be used to improve physical strength and endurance. It is classified as a nootropic because it sensitizes neurons and provides mental stimulation.
Habitual caffeine use is also associated with a reduced risk of Alzheimer's disease, cirrhosis, and liver cancer.
Caffeine’s main mechanism concerns antagonizing adenosine receptors. Adenosine causes sedation and relaxation when it acts upon its receptors, located in the brain. Caffeine prevents this action and causes alertness and wakefulness. This inhibition of adenosine can influence the dopamine, serotonin, acetylcholine, and adrenaline systems.
Habitual caffeine use leads to tolerance. This means the effects of caffeine will be diminished, often to the point where the only benefit a user experiences is caffeine’s anti-sleep effect. This is an ‘insurmountable’ tolerance, which means more caffeine will not overcome it. A month-long break from caffeine will reduce tolerance.
For practical tips on the optimal use of caffeine, check out our Supplement Guides.
- Coffee extract
- Tea extract
- 1 3 7-Trimethylxanthine
- Caffeic acid
Caffeine dosages should be tailored to individuals. If you are new to caffeine supplements, start with a 100mg dose. Typically, 200mg of caffeine is used for fat-burning supplementation, while higher doses of 3–6 mg/kg of body weight are typically used to increase strength.
Many of caffeine’s effects, including fat burning, strength benefits, and euphoria, are subject to tolerance, and may not occur in people used to caffeine, no matter how large the dose is.
There are benefits associated with chronic caffeine consumption, and there are benefits associated with acute caffeine consumption that fade with tolerance; if you like the latter, cycling is mandatory. If you like the former, cycling is not needed.
Over the course of a day, you get sleepy as adenosine binds to A1 receptors in your brain. Caffeine blocks adenosine from binding, thus making you feel alert and also helping you feel better.
Case studies have linked energy drinks to adverse effects, especially on the cardiovascular system, but the overall risk of something bad happening is low and context-dependent.