Caffeine is a psychoactive nootropic compound that is found in many universally and regionally popular beverages, including coffee, various teas, carbonated soft drinks, and yerba mate. Caffeine can help to improve mood, memory, and focus through a range of mechanisms.
Caffeine Usage Across The World
Due to its popularity, it is estimated to be the most commonly consumed psychoactive drug in the world today (1). Like most of the world, Americans are heavy caffeine users. A review estimated that 85% of the US population consumed at least one caffeinated beverage per day (2). The results are based on data from a survey of 37,602 randomly selected consumers. The most popular drink is coffee, followed by carbonated soft drinks and tea. Those three beverages together account for 96% of all caffeine use in the United States.
A smaller proportion of the population consumes caffeine from other sources, including high-caffeine energy drinks and in capsule form, often combined with other compounds.
Why Do People Use Caffeine?
Due to the different concentrations of caffeine across beverages, as well as the presence of other neuroactive compounds specific to each drink, caffeine users experience slightly different effects depending on their mode of intake.
Common to most caffeine users are increased feelings of alertness and improvement in mood. Because of these effects, caffeine is considered to be a nootropic in moderate doses. The dosage is key – at higher doses, the nootropic effects are replaced by potentially unpleasant side effects such as jitteriness, an increased heart rate, and anxiety.
Consumed in appropriate doses (100-400 mg), caffeine can be a powerful and healthy way to increase your cognitive performance and overall mood without any corresponding negative consequences.
So how does caffeine work to improve mood, memory, and focus?
Caffeine Is A Central Nervous System Stimulant
The primary acute effects of caffeine occur through its antagonism of adenosine receptors in the central nervous system (CNS). Antagonists are chemicals that specifically bind to a certain receptor type without activating the corresponding cascade of biochemical signals which produce the intended result.
Adenosine is a neurotransmitter that normally functions to induce sleepiness and drowsiness as part of the natural sleep cycle. Its concentration modulates throughout the day in various brain regions associated with sleep-wake cycle regulation, primarily the basal forebrain and the cortex. Its concentration is lowest immediately after waking and highest immediately before sleep (3).
Although its concentration is not affected by caffeine, its ability to bind to its receptors is decreased due to the blocking effect of caffeine. Caffeine antagonizes two of the four subtypes of adenosine receptors (A1 and A2a), markedly decreasing the neurotransmitter’s effect on the CNS (4, 5).
Caffeine’s effect on CNS stimulation was assessed in one study by measuring the brain activity of mice. Caffeine increased locomotor activity by up to four times compared to mice given a saline control (6).
In another study, researchers found that caffeine increased wakefulness in mice possessing a functional A2a receptor gene, but not in those mice who had mutations resulting in a non-functional copy of the receptor (7). A third study showed that caffeine increased brain activity in mice by up to 40% (8).
CNS Stimulation Improves Brain Function
As a CNS stimulant, caffeine acts to increase alertness, focus and energy levels. Caffeine increases levels of serotonin – the neurotransmitter associated with mood – while increasing energy levels by releasing and adrenaline and acetylcholine (9).
Caffeine also increases the release of dopamine (10). Although this is popularly thought of as the ‘chemical of pleasure’, it is actually considered to play a more prominent role in motivating one’s motivation towards or away from some kind of goal or stimulation – meaning it can increase your focus and attention towards achieving various goals (11).
In a study conducted for the military, 50 males between the ages of 18 and 32 were randomly given treatments consisting of various amounts of caffeine or a placebo after a period of sleep deprivation.
They were then subjected to a variety of standardized testing procedures measuring memory recall, reaction times, logical reasoning, and the ability to sustain attention on a task. Those subjects given caffeine produced significantly better results in these measures of brain function (12).
Caffeine Helps To Consolidate Memories
Until recently, caffeine was considered not to aid in memory formation. Studies that tested the effect of caffeine on memory gave the treatment before the studying part of the trial, and while the familiar increases in alertness were observed, memory consolidation appeared to be unaffected.
Later on, researchers thought to test whether caffeine given after the study session had any effect on subjects’ ability to recall the material after the fact.
In a randomized, double-blind study, 160 subjects were either given a 200mg dose of caffeine or a placebo following the memorization of picture-based patterns. The caffeine group performed significantly better at the recall task, especially in their ability to discriminate between images that were similar, but not identical to those shown in the study session (13).
Caffeine Improves Performance During Natural Low-Points
Further study showed that this effect can be used to overcome the time-based discrepancies in memory recall that occur naturally throughout the day. It is well-established that older adults experience a physiological low point in the afternoon and evening, resulting in a decline in recall ability.
For younger adults, this point occurs in the morning. This affects the ability of students to study and take exams in the morning. In a randomized, placebo-controlled trial, it was shown that caffeine helped subjects overcome these low points. Older adults given caffeine showed no decline in recall ability in the afternoon, while younger adults showed a great improvement in the morning (14).
Researchers have also found examples of this effect in nature, in a study of honey bees’ ability to remember the scents of certain nectar-containing flowers. They found that when plants naturally contain caffeine, bees are three times more likely to consolidate the memory of that flower’s odor (15).
The study also proposed a mechanism of action. Caffeine’s antagonism of adenosine receptors could have a potentiating effect, meaning that it amplifies the ability of neurons to form new connections. Since memory formation involves the formation of new neural pathways, this could go some way to explaining the memory-enhancing effects of caffeine.
Further research is needed to confirm exactly how caffeine aids in memory formation. Still, it appears that consuming caffeine after studying improves the ability to consolidate those memories on a long-term basis, a useful effect for academic study and work-related contexts.
Caffeine Increases Production Of Mood-Enhancing Hormones
Coffee has a popular reputation as a mood enhancer. People say things like “I’m much nicer after my morning cup of coffee”, describing increased happiness, calmness, and satisfaction while under the influence of the drug.
It’s not hard to understand why. As already described, caffeine’s activity on the CNS increases the concentration of serotonin and dopamine in the brain (16). Both of these neurotransmitters are heavily involved in the brain’s native reward pathways.
These pathways are activated by certain stimuli including eating food, exercising, and during sexual activity – behaviors that contribute to an organism’s likelihood of survival. They produce a distinct feeling of pleasure and satisfaction that the organism, whether it is a mouse or a human, wants to recreate. The reward pathways evolved to increase the likelihood of repeating the behavior in question.
Caffeine also increases the production of epinephrine, also known as adrenaline. This is normally released during states of arousal and helps us to feel active and excited – it is one of the primary excitatory hormones of the CNS.
By increasing the production of these various hormones and neurotransmitters, caffeine helps to bring about an active and excited state of mind.
Caffeine Improves The Mood Of Study Participants
Testing the effect of caffeine on mood is an inherently subjective exercise, given that the data collected must be self-reported by the study participants in the form of survey answers. Nonetheless, these uncertainties can be overcome by double-blind, randomized testing combined with statistical techniques.
In one study, the group given a moderate dose of caffeine reported greater feelings of relaxation, happiness, and satisfaction when compared to a group who were given a placebo (17). These mood-enhancing effects were observed irrespective of the subjects’ regular level of caffeine usage, suggesting these effects are not part of the tolerance built up by regular caffeine users.
Another study agreed with the finding that caffeine increased self-reported mood levels, but found that the effects were stronger when subjects had not consumed caffeine in the past 24 hours (18).
A third paper combined a variety of data from survey responses to produce four mood categories: sedation, tense arousal, energetic arousal, and hedonic tone. Energetic arousal was defined as an increase in energy and alertness without a corresponding increase in anxiety or stress, while hedonic tone was a measure of the positivity or negativity shown by subjects to the same stimuli depending on their state of mind.
In the double-blind trial, participants given caffeine scored higher in energetic arousal and hedonic tone regardless of the amount of caffeine consumed. Sedation increased at low levels of caffeine intake, while tense arousal increased at higher levels of consumption (19).
Negative Effects of Caffeine
Too Much Caffeine Can Have The Opposite Effect
Although moderate doses of caffeine can boost your mood, memory, and focus, too much can have the opposite effect as intended. The same action at the adenosine receptor that is responsible for the primary effects of caffeine also triggers anxiolytic (anxiety generating) pathways which result in the perception of stress and nervousness (20).
In a behavioral study of mice, caffeine and another antagonist specific to the A1 receptor increased anxious behaviors, whereas a third antagonist specific to the A2a receptor did not (21).
Since the primary action of caffeine is at the A2a receptor (6), doses of caffeine that are too high increase the effects of the anxiolytic A1 receptor, increasing the anxiety-provoking component of its effect.
As a CNS stimulant that releases epinephrine, caffeine also increases blood pressure and heart rate. Too much caffeine results in an uncomfortable increase in these parameters, which explains the ‘jitters’ phenomenon commonly described by those who have had too much caffeine.
Is Caffeine Helpful Or Harmful?
As we have seen, caffeine has the potential to induce useful, nootropic effects, while also leading to negative and potentially harmful side effects at higher doses. So, it is important to consume the right dosage of caffeine to ensure it functions as an enhancer in your body.
Researchers formulating drugs for production use a concept called the therapeutic window. By manipulating various factors, they can produce a formulation that releases the drug more quickly or slowly into the bloodstream, therefore keeping a patient’s blood concentration of a compound between the minimum effective level and the level at which side effects are experienced for the maximum amount of time.
When caffeine is consumed in beverages, it enters the bloodstream quickly. When consuming coffee and cola, the peak in serum concentration was around 45 minutes after consumption, while it was closer to 70 minutes when caffeine was consumed in capsule form. After about 12 hours, a moderate dose of caffeine will have been fully excreted (22).
Caffeine’s effects are also different depending on the specific neurochemistry of the person taking it. What might be an effective, nootropic dose for one person may make another person unpleasantly anxious. Preliminary evidence suggests that people who suffer from panic disorders have an increased sensitivity to the ill effects of caffeine and are more likely to abstain from its consumption as a result (23).
How To Achieve The Best Effects From Caffeine
Achieving a nootropic effect from caffeine requires having a little bit more often, rather than having a lot all at once, which can lead to negative side effects followed by a corresponding crash.
Due to the variation in caffeine concentration in beverages depending on the brewing method, it can be hard to predict exactly how much caffeine one is taking. A cup of coffee usually contains about 80-100mg of caffeine, but this depends on the coffee.
A medium-sized cup of Starbucks coffee contains about 330mg of coffee, almost all of the recommended maximum daily dose of 400mg. What’s more, the same sized cup of coffee from Dunkin’ Donuts contained almost 100mg less caffeine when tested side by side (24).
It can be useful to take caffeine as a supplement in pill form, rather than as a drink. This way, you can be sure of exactly how much you are taking, making it easier to stay in the therapeutic window and experience the corresponding increases in mood, memory, and focus.
Some caffeine pill formulations also contain compounds to alleviate side effects, making them more useful as nootropic supplements. The most common of these is L-Theanine. The combination of this amino acid and caffeine occurs naturally in green tea and is responsible for the reported psychoactive effects of the drink.
The combination of the two compounds was shown to increase cognitive performance more than the placebo or either compound alone, according to a randomized trial that used subjective performance tests while also electrically measuring brain activity (25).
Before the modern wealth of research on caffeine’s effects was accumulated, caffeine usage – in particular, coffee drinking – was thought to be an unhealthy habit, like smoking cigarettes or drinking alcohol. Science has shown that the opposite is true: caffeine usage confers a whole host of physiological benefits.
Moderate doses of caffeine – usually under 400mg a day, though the limit is different for different people – can heighten your focus, improve your mood, and aid your memory. It is, therefore, an ideal nootropic, capable of improving your mental performance in a variety of contexts, including studying and at work.
In contrast, too much caffeine can have the opposite effect. Uncomfortable physical conditions, usually perceived as ‘the jitters’, can result from too high a dosage. These can come with anxiety levels. Some people, especially those suffering from panic disorders, may be more sensitive to these effects.
To get the balance right, the user must pay attention to how they are taking caffeine and in what form. To this end, nootropic formulations can help. Taking caffeine in a capsule form results in a slower release, as well as providing an easy way to control your dosage. To top it off, synergistic compounds that help to improve the positive effects and negate the negative ones can be included in the formulation.
Appropriate consumption of caffeine confers a host of benefits to the user, which makes it a great nootropic. Its worldwide popularity suggests that most people already know this – but with a more conscious usage, the improvements in your focus, mood, and memory can be even greater.