Caffeine and other supplements for esports players: what the evidence says
Summary
What is it? A look at whether caffeine and other supplements improve the thinking and game performance of esports players. The main source is a 2026 systematic review and meta-analysis of 13 randomised trials [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. A meta-analysis combines the numbers from several studies into one estimate.
Why would I need it? Esports depends on fast reactions, attention and quick decisions, and players often look for a small edge before long matches or training sessions.
Is it useful? Possibly, for reaction speed and for tasks that need flexible thinking, but the evidence is weak. Across 38 results from 13 trials, supplements improved performance with a pooled effect of g = 0.92 (95% CI 0.64 to 1.21) [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. The review rated the certainty of the evidence as low for four of five outcome groups, and a second review of the same question also called its findings preliminary [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026[2]Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D, Zheng Y, Xu M, et al. J Int Soc Sports Nutr, 2026.
FAQ
Does caffeine improve esports performance? Possibly. Nine of the 13 trials tested a product that contained caffeine, and the pooled result was positive. But the review mixed caffeine products with other supplements, so the figure is not a clean estimate for caffeine alone [1 Table 1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
What does g = 0.92 mean? Hedges' g is a standard way to express a difference between two groups in units of the spread of the results. A value of 0.92 means the supplement groups scored almost one standard deviation better than the placebo groups on average. This is usually called a large effect, but the review's own checks suggest it is too high [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Is the effect really that big? Probably not. A test for publication bias found that small trials reported larger effects than big ones. When the review adjusted for likely missing negative results with a method called trim and fill, the estimate fell from 0.92 to 0.49 (95% CI 0.21 to 0.76). That is still a positive result, but about half the size [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Which skills improved most? Processing speed, meaning reaction time to what is on the screen (g = 1.18), and executive function, meaning flexible thinking, working memory and decision-making (g = 1.06). Game performance (g = 0.78) and accuracy (g = 0.71) also improved. Attention and inhibition did not reach statistical significance (g = 0.50, p = 0.095) [1 Table 2]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Does it work in every kind of game? Not clearly. The effect was significant in laboratory cognitive tasks (g = 1.07) and in first-person shooter tasks (g = 0.96). It was not significant in MOBA games such as League of Legends (g = 0.59, p = 0.062), but the review counts only 3 in each of these game groups, so a real difference is not proven [1 Table 2]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Do professionals benefit as well as amateurs? The review found significant gains in both groups, g = 0.97 for professional or elite players and g = 0.92 for amateurs. The review counts only 3 in the professional group [1 Table 2]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Does a higher caffeine dose work better? The review found no link between dose and effect, in the range from 0.49 to 3 mg/kg of body weight. With so few trials this does not show that all doses work equally well [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Is caffeine safe at these doses? The European Food Safety Authority (EFSA) says that single doses of caffeine up to 200 mg, about 3 mg/kg for an adult, and intakes up to 400 mg a day do not raise safety concerns for healthy adults. It adds that 100 mg close to bedtime may disturb sleep in some adults [3]Caffeine: safety of caffeine. European Food Safety Authority (EFSA). The trials in the review were mostly single doses, and the authors say long-term safety was not tracked [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Article
What was studied
The review searched six databases up to 25 January 2026 and included only randomised trials with a placebo that matched the supplement. Thirteen trials from 2019 to 2025 were included, with 743 participants in total. Individual trials had between 18 and 122 people, and the average age was 20.4 to 24.5 years [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. The authors registered the plan of the review in advance in PROSPERO, a public register of reviews [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Because most trials measured several outcomes in the same group of people, the authors used a three-level model. This model avoids counting the same people twice. In all, 38 results from the 13 trials were pooled [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
The trials
| Supplement | Trials | Dose | Game or task |
|---|---|---|---|
| Caffeine capsules or drink | 4 | 2 to 3 mg/kg | CS:GO, shooting tasks, League of Legends |
| Caffeine with TeaCrine and Dynamine | 2 | 125 to 200 mg caffeine | Aim Lab, computer tests |
| Caffeine energy drink with taurine and B vitamins | 1 | 200 mg caffeine | reaction and attention tasks |
| Caffeine with L-theanine and Bacopa monnieri | 1 | 100 mg caffeine | several games |
| Guayusa tea extract | 1 | 200 mg extract, 40 mg caffeine | shooting training |
| Arginine silicate inositol (nooLVL) | 2 | 1.6 g | League of Legends, lab tasks |
| Gamma-aminobutyric acid (GABA) | 1 | 100 mg | Apex Legends |
| Mango leaf extract (Stadice) | 1 | 300 mg | several games |
The table groups the products listed in the review's Table 1 [1 Table 1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. Ten trials had only male players, and three included some women, always fewer than 20% of the group [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
What each outcome showed
| Outcome group | Results pooled | Effect (g) | 95% CI | Certainty (GRADE) |
|---|---|---|---|---|
| Processing speed | 12 | 1.18 | 0.79 to 1.57 | Low |
| Executive function | 8 | 1.06 | 0.57 to 1.54 | Low |
| Game performance | 7 | 0.78 | 0.33 to 1.22 | Low |
| Accuracy | 5 | 0.71 | 0.15 to 1.27 | Low |
| Attention and inhibition | 6 | 0.50 | -0.09 to 1.08 | Moderate |
Results are from Table 2 and Table 3 of the review [1 Table 2]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. GRADE is a system that rates how much confidence the evidence deserves. The attention result was rated moderate even though it was not significant, because, unlike the other four groups, it had no serious concern about risk of bias [1 Table 3]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
How other reviews compare
A 2021 meta-analysis of caffeine and cognition in sport found significant effects of caffeine on attention, accuracy and speed, and said that low to moderate doses before or during exercise may also help simple and choice reaction time [4]Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis. Lorenzo Calvo J, Fei X, Domínguez R, et al. Nutrients, 2021. A 2026 systematic review of 13 trials in esports players, 14 of whose 18 supplement protocols contained caffeine, reported better attention, executive function and shooting performance, and called its findings preliminary [2]Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D, Zheng Y, Xu M, et al. J Int Soc Sports Nutr, 2026. A 2025 network meta-analysis of 12 studies found that caffeine combined with taurine improved reaction time more than either alone (g = 0.75) [5]Caffeine and taurine: a systematic review and network meta-analysis of their individual and combined effects on physical capacity, cognitive function, and physiological markers. Deng H, Wang L, Liu P, et al. J Int Soc Sports Nutr, 2025. These reviews agree on the direction, but none of them shows that the size of the effect in competitive esports is as large as g = 0.92.
Limits of this evidence
- Small trials. Each trial had 18 to 122 people, and many had fewer than 50 [1 Table 1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- Publication bias. A statistical test found small-study effects. After adjustment, the pooled effect dropped from 0.92 to 0.49 [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- High inconsistency. Results differed a lot between trials (I2 above 75%), partly because the products, games and tests differed [1 Table 3]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- Mixed products. Nine of the 13 trials contained caffeine and four did not. The review calls its result an effect of nutrition, and at times of caffeine, but it cannot separate the two [1 Table 1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- Mostly men, mostly single doses. Few women took part, and the trials looked at the effect of one dose, not at long use [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- Some inconsistencies in the paper. The review gives the dose range tested in the dose analysis as 0.49 to 3.00 mg/kg in the Results but 2 to 6 mg/kg in the Discussion, and the p-values differ (0.958 and 0.45). The confidence interval of the professional group is the same as that of the shooting-game group [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
- Risk of bias is rated differently. The main review rated 9 of 13 trials as low risk of bias [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026. A second review of 13 trials raised concern about risk of bias in more than half of its studies [2]Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D, Zheng Y, Xu M, et al. J Int Soc Sports Nutr, 2026.
- Funding and ties. The authors state no specific funding and no conflicts of interest [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
What the authors suggest
The authors suggest that low doses of caffeine, in the range 0.5 to 3 mg/kg, are a reasonable "minimum effective dose" to study in esports. This is their view. They also estimate, as speculation, that the supplements might shorten reaction time by 15 to 25 ms, and no trial measured this [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026.
Talk to a doctor before you start a supplement, especially if you take medicines or are pregnant.
Verification
Checked on 2026-11-10.
| Claim | Result | What the check found |
|---|---|---|
| Supplements, mostly caffeine, improve reaction speed and attention-type tasks in people who play or train | Partly verified | A 2021 meta-analysis found significant effects of caffeine on attention, accuracy and speed in sport, and a 2026 review of esports trials found better attention, executive function and shooting performance. Neither gives the same effect size. Both were read as abstract only [4]Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis. Lorenzo Calvo J, Fei X, Domínguez R, et al. Nutrients, 2021[2]Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D, Zheng Y, Xu M, et al. J Int Soc Sports Nutr, 2026 |
| The pooled effect is g = 0.92 | Not verified | No second source gives a pooled figure for esports. The review's own trim-and-fill estimate is 0.49 [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026 |
| Caffeine up to 200 mg per dose and 400 mg a day is not a safety concern for healthy adults | Verified | The EFSA page gives the same limits and the 100 mg warning near bedtime. This is a statement on safety, not on whether the dose works [3]Caffeine: safety of caffeine. European Food Safety Authority (EFSA) |
| Caffeine with taurine helps reaction time | Partly verified | A 2025 network meta-analysis found g = 0.75 for reaction time with caffeine plus taurine compared with either alone, but the energy drink trial in the esports review was a single trial [5]Caffeine and taurine: a systematic review and network meta-analysis of their individual and combined effects on physical capacity, cognitive function, and physiological markers. Deng H, Wang L, Liu P, et al. J Int Soc Sports Nutr, 2025 |
| Dose and effect are not linked | Not verified | No second source on esports dose. The paper's own dose range and p-value differ between sections [1]Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026 |
| Risk of bias is mostly low | Contradicted | The second review found concerns in over half of its trials. The two reviews count participants differently (743 and 466), and their abstracts do not list the trials, so overlap was not checked [2]Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D, Zheng Y, Xu M, et al. J Int Soc Sports Nutr, 2026 |
See also
Sources
Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J, He J, Hu E. J Int Soc Sports Nutr, 2026
Meta-analysis · About this source- Systematic review · About this source
Caffeine: safety of caffeine. European Food Safety Authority (EFSA)
- Meta-analysis · About this source
- Systematic review · About this source