Most of us are familiar with caffeine from tea, coffee and some soft drinks. It is a powerful central nervous system stimulant, and has the distinction of being the world's most consumed psychoactive drug!
Caffeine is widely known to boost mood and to enhance focus and alertness. It is thought to do this by inhibiting the effects of adenosine, a neuromodulator which causes drowsiness. It has also been shown to have an ergogenic effect, enhancing sports performance and stamina, probably due to increased adrenaline levels in the blood following caffeine consumption.
Controlled trials have shown evidence that caffeine may help to boost memory and cognitive function, and may benefit those suffering with Alzheimer's or dementia. Caffeine speeds up the metabolism, and may therefore help with fat burning. Early research suggests that caffeine may also help to protect against diabetes, Parkinson's and liver disease.
Caffeine can be consumed as part of your normal daily diet, usually in a drink such as tea or coffee. However, you can also buy caffeine supplements, typically in tablet or capsule form, which are designed to provide extra energy and mental alertness. Caffeine can be mildly addictive, so take care with the levels you consume.