Caffeine
Other names Guaranine, Theine, Methyltheobromine
Caffeine is the most widely used psychoactive drug in the world. People use it to feel and perform better, and often say they experience improvements in alertness, focus, and mood. But what does the science say about the effectiveness of caffeine as a cognitive enhancer? Read on to find out.
Benefits
Read about the effects of Caffeine in relation to the amount of evidence we've found
Why do people use caffeine?
People who self-experiment with caffeine often state they use it to improve their:
- Focus
- Mood
- Energy
- Physical performance
Is caffeine effective for any of these purposes in healthy humans?
We analyzed data from 7 placebo-controlled studies on the effects of Caffeine in healthy humans and summarized the results here:
| Effect | Effect size | Evidence amount |
|---|---|---|
| Memory | Minute positive | Relatively large |
| Energy | Minute positive | Relatively large |
| Focus | Minute positive | Relatively large |
| Mood | Minute positive | Relatively large |
| Sleep | Minute positive | Relatively large |
Risks
The legality and side effects of Caffeine
You should always consider the risks of a nootropic before you use it.
Side effects
No negative side effects were seen in any of the studies that we reviewed.
Interactions
Supplements and drugs can interact with Caffeine to increase or decrease the positive or negative effects you experience. If you are already using any supplements or drugs, speak with your trusted medical professional before you experiment with Caffeine. To learn more about the potential interactions between Caffeine and other substances, use interaction-checker.
Legality
Is your country not included? Learn how to find out if Caffeine is legal in your country.
Legality Disclaimer
The contents herein are not legal advice or a substitute for legal counsel. information is not intended to create, and receipt of it does not constitute, an attorney-client relationship. While we have done our best to be as accurate as possible in the information we convey to you about the legality of nootropics, there is a risk for inaccuracies and errors. If you’re uncertain about the legality of any of your actions, contact a legal counsel or your local authorities governing the legality of various substances you may want to use/import/travel with.
How To Use
Dose, frequency and duration
It is usually safer and more effective to use nootropics as they have been used in studies on humans. In the only study that we’ve reviewed, Caffeine was used in the following ways:
FAQ
Frequently asked questions about Caffeine
How do I maximize the nootropic benefits of caffeine?
Caffeine has the strongest cognitive effects when you do not have a tolerance to it. [38] The time it takes to reset caffeine tolerance is different from person to person but is usually around 14 days.
What do nootropics researchers say about caffeine as a cognitive enhancer?
Steven Roodenrys (Ph.D. in cognitive psychology and nootropics researcher) commented that the evidence, on the whole, suggests that caffeine is indeed an effective cognitive enhancer. [39] Specifically, his take on the science of caffeine is that it can improve alertness, concentration, and learning, but that one should be aware of tolerance, addiction, and other risks (e.g. anxiety). A dose of at least 100mg appears to be required for caffeine consumption to result in cognitive enhancement, according to Roodenrys.
Andrew Scholey, (Ph.D. in psychopharmacology and nootropics researcher) also said he thinks caffeine is effective and that dose and tolerance are important factors that influence how caffeine will affect your mental performance.
How fast do you build a tolerance to caffeine?
A certain degree of tolerance builds up already after the first dose of caffeine. After the first day of caffeine use, you'll likely need more of it to get the same effects as you had the previous day.
It was found in one study that the physical performance enhancement effects of (200mg) caffeine persist but are progressively lessened during the first 3 weeks of daily use. [42] Another study found that the benefits of caffeine for physical performance enhancement were completely gone after 4 weeks of daily use. [43] The effects of caffeine are best when you have no tolerance to it, but it takes several weeks for caffeine tolerance to develop fully.
As regards tolerance to the cognitive and affective effects of caffeine, the strongest science available suggests that you do build a tolerance to the mood benefits and to the improved reaction time performance that caffeine results in when used by people without a tolerance. [44]
However, it was also found that caffeine "... improved selective attention and memory in both the abstained and normal caffeine states". [45] This means that even if you have a tolerance to caffeine, there may be some cognitive benefits to using it, but likely no mood improvements. Some studies have found that mood and reaction time decrease to impair baseline performance after prolonged daily use of caffeine. [46] This effect is likely reversible if you quit caffeine to reset your tolerance.
How fast do you get back to baseline when quitting caffeine?
This depends on the individual person and situation. Factors like genes, the dose of caffeine, duration of caffeine use, and lifestyle (e.g. nutrition, exercise, sleep), all play a role in how long it will take before your body has fully reset its tolerance to caffeine.
In general, it takes at least 10 days of zero caffeine to fully reset a tolerance to caffeine.
If you have been using a lot of caffeine for a long time, it is likely better to slowly reduce your caffeine intake each day to avoid the negative side effects that can occur from abrupt abstinence.
What can I replace caffeine with?
There are many promising but relatively underresearched caffeine alternatives that preliminary evidence suggests boost mood, memory, focus, and energy. Here are some of the most science-backed ones:
How can I consume more caffeine?
Caffeine is present in high amounts in:
- Cocoa (230mg/100g[52])
- Coffee (40mg/100ml[54])
- Yerba maté (32.5mg/100ml[56])
- Black tea (22mg/100ml[58])
- Green tea (15mg/100ml[60])
What substances stack well with caffeine?
Caffeine is often a part of nootropic users' "stacks" (combinations of several substances that may work synergistically in the brain to enhance cognitive performance).
The classic caffeine and l-theanine stack which many people have reported that they get a good focus with no nervousness from contains 100mg caffeine and 200mg l-theanine. If you've never combined two nootropics into a stack before, this is a good beginner stack for you with a high probability of positive effects with low risk for negative side effects.
You may already have used nootropic stacks with caffeine in them without knowing:
”What’s really interesting about how we normally ingest caffeine is that it’s ingested with vasodilators. So if you look at caffeine in tea, tea contains catechins which we know increase blood flow. If you look at caffeine in coffee, coffee contains these things called chlorogenic acids which again increase blood flow. [...] Humans tend to ingest caffeine in a form which not only have you get caffeine in there but also there are these substances which oppose the reduction in blood flow.” ~ Nootropics researcher Andrew Scholey on the Nootralize podcast.
How does caffeine work in the brain?
It blocks adenosine receptors which reduces fatigue through a slowed-down catecholamine decrease in the brain. Catecholamines are generally stimulating neurotransmitters that decrease in concentration in the brain throughout the day. [68]
Is caffeine neuroprotective?
Caffeine has been found neuroprotective against certain neurodegenerative disorders in humans. Specifically, it is beneficial for patients with Parkinson’s and Alzheimer’s disease. [69]
It has also been found neuroprotective in several animal studies. [70][71]
The neuroprotective effects of caffeine probably depend on what the factor that is damaging neurons in the brain is. For example, lack of oxygen or dangerously high glutamate levels in the brain can lead to increased neuronal death. While caffeine may be protective in many instances, it is likely not going to protect you from anything you might expose your brain to.
What time of day should you take caffeine?
Caffeine is known to promote wakefulness and alertness and directly blocks one of the body's own sleep-drive chemical (adenosine) from binding to its receptors and exerting its effects. Caffeine has a half-life of between 1.5 and 9.5 hours, usually between 2.5–4.5 hours (it varies by individual). [72][73][74] This means it takes several hours before your body has gotten rid of half of the caffeine you ingested. Caffeine can objectively impair your sleep if used too soon before going to bed [75], meaning you won't necessarily feel the negative effects caffeine has on sleep.
We, therefore, recommend that you do not use caffeine before bed-time, and preferably not even at all during the afternoon. If you can, use caffeine only in the morning or at least not after lunch to avoid its negative effects on sleep.
Who should use Caffeine?
There’s a need for more high-quality scientific information about the safety and effectiveness of Caffeine. Specifically, there’s a great degree of individual variance in how people respond to nootropics in general and Caffeine in particular. This means that if you use Caffeine, you may not experience the same effects as those that were seen in scientific studies on it.
It is currently largely unknown what factors play a role in whether a nootropic will be effective for a person.
While we wait for science to explain who is likely to respond to which nootropics, patient self-experimentation with nootropics that have been found safe and effective in placebo-controlled studies in healthy humans is a proven strategy to feel and perform better with the help of nootropics.
Studies
Studies conducted on the effects of Caffeine in healthy humans
In the 7 studies that met our inclusion criteria, 278 participants received Caffeine. In total, we examined 37 studies on the effects Caffeine, which you can find summaries of below.
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
Caffeine, in a large single dose, reduced calmness and increased the amount of time participants slept
Study groups
Adults using 600 Milligram
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
Caffeine did not enhance cognitive performance in this study on healthy young adults
Study groups
Adults using 150 Milligram
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
"This study demonstrated that in healthy adult subjects oral administration of a single 60 mg caffeine dose elicited a clear enhancement of sustained attention and alertness, measured both in multiple objective performances and in subjective scales."
Study groups
Adults using 30 Milligram
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
"The results indicate that the synergistic effects of caffeine and glucose can benefit sustained attention and verbal memory, even with adequate levels of activation of the subjects."
Study groups
Adults using 75 Milligram
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
"The study showed that the effects of caffeine consumption on a cognition test in an at-home setting revealed similar results as in a controlled setting. The Go-No Go test applied showed improved results after caffeine intake, similar as seen in clinical trials. This type of study is a fast, reliable, economical, and easy way to demonstrate effectiveness of a supplement and is rapidly becoming a viable alternative for the classical randomized control trial to evaluate life style and nutritional interventions."
Study groups
Adults using 170 Milligram
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
"The results of this study suggest that acute caffeine ingestion positively enhances functional performance, manual dexterity and readiness to invest effort in apparently healthy older adults."
Study groups
Adults using 231 Milligram
Summary
"Caffeine administration induced arousing effects (lesser somnolence and greater activation) in all post-consumption records, while the effects of decaffeinated drink were only apparent at 10 min."
Summary
"YOH shifted the healthy subjects' mood towards feeling panicked, elevated systolic blood pressure and plasma prolactin concentrations, reduced digit symbol substitution, and induced drowsiness and passiveness."
This study is used in our recommendation engine calculations. Learn more about how we select studies
Summary
Alpha-GPC had no ergogenic effect in healthy adults
Study groups
Adults using 200 Milligram
Summary
"The results showed that caffeine led to a more positive mood and improved performance on a number of tasks."
Summary
"Compared to placebo, participants receiving the citicoline-caffeine beverage exhibited significantly faster maze learning times and reaction times on a continuous performance test, fewer errors in a Go No-Go task, and better accuracy on a measure of information processing speed."
Summary
"Eleven reviews (with a total of 21 meta-analyses) were included, all being of moderate or high methodological quality (assessed using the Assessing the Methodological Quality of Systematic Reviews 2 checklist)."
Summary
"The results of the present study indicate that acute doses of CAF before exercise does not have a significant effect on power output and bar velocity in a group of habitual caffeine users."
Summary
"Caffeine consumption led to significantly faster response times, but only for participants who typically consumed relatively little caffeine."
Summary
"We conclude that all drugs tested improved at least some aspects of cognitive and motor performance after sleep deprivation."
Summary
"Diazepam alone produced sedation, lowered other ratings of subjective moods, and impaired cognitive, learning, and memory performance."
Summary
"The results of the present study indicate that high acute doses of CAF (9 and 11 mg/kg/b.m.) did not improve muscle strength nor muscle endurance in athletes habituated to this substance."
Summary
"When subjects were divided into groups of caffeine-sensitive choosers and nonchoosers, a consistent relationship emerged between caffeine choice and subjective effects; nonchoosers reported primarily aversive effects after caffeine (increased anxiety and dysphoria), whereas choosers reported stimulant and ´"positive" mood effects. When compared with previous findings, these results demonstrate that caffeine is less reinforcing than amphetamine and related psychomotor stimulants."
Summary
"Findings revealed that caffeine administration relative to the placebo condition resulted inheightened WM performance, but only for extraverted participants."
Summary
"These data show that caffeine is a useful method for manipulating arousal in the laboratory without influencing feelings of pleasantness or learning and memory performance."
Summary
"Given the interaction between these two variables (activity and caffeine), we can assume that they both increase general activation in a similar way. However, the absence of interactions between Intake and Activity with regard to orienting and executive control suggests that exercise and caffeine are different modulators of attention."
Summary
Summary
"We conclude that the morning caffeine "fix" has positive attentional effects and selectively improved executive updating whether or not caffeine is consumed with food."
Summary
"These results suggest that caffeine has a specific benefit for memory during students’ non-optimal time of day – early morning. These findings have real-world implications for students taking morning exams."
Summary
"The results showed that Caffeine increased alertness and improved psychomotor speed and the accuracy of verbal reasoning."
Summary
"... in this study a moderately high dose of CAF significantly increased the average power during a Wingate test, yet it does not affect peak power or static hand-grip strength."
Summary
"Caffeine and theophylline increase psychomotor performance measures of attention at low plasma concentrations in healthy elderly volunteers. This effect is not increased by higher drug concentrations and there is trend towards a return to placebo scores. The lack of effect of both caffeine and theophylline on subjective measures is consistent with previous studies of caffeine in the elderly."
Summary
"In conclusion, blood pressure response is augmented and subjective feelings of behavioral mood state are attenuated to a greater degree in older than in younger women following acute caffeine ingestion."
Summary
"Caffeine increased exercise endurance in healthy citizens aged > or =70 yr, but the participants' reasons for stopping the test may have varied between subjects, as the cycling test was done at approximately 55% of maximal oxygen consumption."
Summary
"Caffeine increased self-rated alertness and jitteriness and blood pressure. Theanine antagonised the effect of caffeine on blood pressure but did not significantly affect jitteriness, alertness or other aspects of mood. Theanine also slowed overall reaction time on the visual probe task."
Summary
"Caffeine significantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not significantly different. These findings provide evidence of the limited benefits of caffeine for memory improvement compared with napping."
Summary
Caffeine enhances cognitive and physical performance.
Summary
"... an increase in hit rate and target discriminability (d') for the combined treatment relative to placebo, and an increase in d' but not hit rate for caffeine alone, whereas no effects were detected for L-theanine alone."
Summary
"A dose of theanine equivalent of eight cups of black tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses."
Summary
"Caffeine increased sleep latency (i.e., improved alertness) and auditory vigilance performance compared to placebo. Tolerance to the effects of caffeine on sleep latency developed over the four administrations. On the conditioning test (day 3) the group receiving caffeine the previous two days was more alert and performed better than the placebo group."
Summary
"Together these results suggest that theobromine and caffeine could have differential effects on mood and blood pressure. It was tentatively concluded that caffeine may have more CNS-mediated effects on alertness, while theobromine may be acting primarily via peripheral physiological changes."
Summary
"The results showed that clonidine reduced alertness, impaired many aspects of performance and slowed saccadic eye movements; caffeine removed many of these impairments."
Last updated Saturday, June 10, 2023