Caffeine: the World’s Most Popular Cognitive Enhancer

31/05/2014 Tags: all

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Whether it be coffee, tea, energy drinks or caffeine tablets, there is no doubt that caffeine is the most widely available and most commonly used psychoactive stimulant in the world. In fact, it has been estimated that the global consumption of caffeine is in excess of 120,000 tonnes which is the equivalent of one cup of coffee per person every day! Although it does not strictly fit the definition of a nootropic supplement, caffeine’s cognitive enhancing effects are well documented with the ability to increase alertness, memory and reasoning skills, particularly in sleep deprived individuals. With all these benefits to offer it is no wonder that caffeine has been used for so many centuries and continues to be so prevalent in our lives today. It is found in over 60 different plant species that are commonly used in food production meaning that most people may be consuming and benefiting from caffeine without even realising it. Ingredients that include guarana berries, kola nuts, cocoa and Camillia sinensis all contain caffeine while it is also used extensively in weight loss supplements and analgesics. Yet despite how commonly used this supplement is, very few people are aware of how it works. This article aims to cover some of the benefits and mechanisms of caffeine.


The Benefits of Caffeine

Caffeine is a stimulant that is known to affect both the central nervous system and metabolism. It is most commonly used to counteract fatigue and drowsiness and has the ability to increase wakefulness, alertness, focus and the ability to think clearly. Studies suggest that caffeine can enhance memory performance while it also appears to have some beneficial effects on mood and indeed it does seem that most people feel more energised and lively after drinking a cup of coffee. With moderate doses, these effects are usually seen within an hour of consuming caffeine and usually diminish after around 5 hours.


These benefits make caffeine useful for a wide number of applications. For example, its ergogenic properties help shift workers and other individuals with unusual sleeping patterns to enhance mental performance and make fewer mistakes due to tiredness. It is also a favourite of students looking to study for longer, meet deadlines and maintain concentration in lectures. Some athletes are also known to use caffeine as a performance enhancer, particularly in competitive and team sports, although its efficacy in this field may be somewhat limited. Research carried out by Coso et al. (2012) does however observe that administrations of 3mg/kg of caffeine given to football players did increase enhance several performance parameters including running speed, high speed distance coverage, jump height and the upper limit of muscle power. There is also some limited evidence that suggests caffeine may be helpful in helping users to adjust to high-altitude environments.




As well as enhancing cognitive performance, caffeine may have other benefits that many people are not aware of. Some studies have actually linked coffee consumption to a reduced risk of certain types of cancers that include hepatocellular (liver) and endometrial (uterine) cancer while it also appears to have a modest effect on colorectal cancers. It should however be noted that caffeine does not significantly reduce the risk of other types of cancer and consuming excessive amounts of coffee may contribute to an increased risk of bladder cancer.

Although caffeine is known to increase both heart rate and blood pressure, there is nothing to suggest that this increases the risk of cardiovascular diseases. One study that produced some rather interesting results suggests that while individuals who consume around 4 cups of coffee a day are not at risk of developing hypertension when compared to those who drink little or no coffee, those drinking 3 cups of coffee did show an increased risk.


As well as being a stimulant for casual use, caffeine is also has several therapeutic applications.

Caffeine acts as a mild bronchodilator that helps to reduce resistance in respiratory airways by expanding bronchioles and bronchi making it useful for obstructive respiratory conditions. Clinical trials have shown increased lung function in sufferers of asthma while caffeine citrate is the primary treatment for apnea in premature children. While some have concerns about possible developmental side effects following caffeine use in infants, long-term follow up studies carried out several years into development showed quite the opposite. The caffeine appeared to have neuroprotective effects and children previously treated with caffeine showed a significantly reduced risk of developing cerebral palsy or other language and cognitive deficits.


Mechanisms of Caffeine

Caffeine works primarily as an antagonist to the neurotransmitter adenosine. Adenosine is an inhibitory neurotransmitter that reduces neural activity and promotes feelings of sleepiness after prolonged periods of mental activity. A similar shape allows molecules of caffeine to bond to adenosine receptors without activating them. By occupying the active sites of such receptors, caffeine can negate the effects of fatigue and help you to feel more alert when deprived of sleep. Caffeine is also known to affect the action of several major neurotransmitters. For example, caffeine modulates dopamine activity that has been linked to regulating executive functions such as attention and concentration.




Caffeine’s physical performance enhancing properties are thought to be explained by increased utilisation of fats as a fuel in the body. Caffeine increases the level of epinephrine circulating in the body which mobilises free fatty acids from adipose tissue and intramuscular triglycerides. These fatty acids are oxidised as a fuel source, allowing the body to reserve muscle glycogen which contributes to greater stamina. Caffeine may also reduce the perceived effort needed to carry out physical activities. This is achieved by lowering the threshold required to activate neurons so muscles become easier to recruit for work.

Caffeine is also metabolised into several substances that contribute to its effects. For example it is broken down mostly into paraxanthine that aids in the process of lipolysis, increasing the amount of fatty acids and glycerol that can be used for fuel by muscles. Lesser amounts of theobromine and theophylline are also produced in the metabolism of caffeine. Theobromine acts as a vasodilator, increasing the amount of blood, nutrients and oxygen that are delivered to muscles and the brain. Theothylline meanwhile has the effect of increasing heart rate and the force of heart contractions which may further aid in increasing blood flow.


Dosage Guidance

The safe daily allowance for healthy adults is 300 to 400mg a day although realistically this may differ greatly between individuals depending on body weight, age and the users sensitive to caffeine. You should be aware that it is possible to build a tolerance to caffeine so using it only occasionally or on a cyclic basis is advised. 


Many people choose to use caffeine as part of a nootropic stack. One popular stack involves using caffeine with L-theanine. This combination of substances can be found naturally in green tea and is believed to work synergistically. Some of the short term side effects of caffeine may be nullified while benefits are enhanced with studies showing greater attention, memory, alertness and visual acuity when both of these supplements are used together. This stack is ideal for those that are already familiar with caffeine or new to stacks as it is both simple to use and cost-effective.


Potential Side Effects

Although caffeine is generally quite safe to use and well tolerated by most, there are some known side effects that may be seen with excessive doses or continuous long-term use. For example dosages exceeding 300mg may result in disruptions to sleep and a rapid or irregular heartbeat. Users may also experience headaches, anxiety and nausea in the short-term while long-term use may lead to tolerance issues and decreased supplement effectiveness.