Caffeine and exercise performance: an expert position stand
What it found
In people, caffeine improved many types of exercise performance, especially endurance, at doses of 3 to 6 mg per kg of body mass.
Benefits varied between individuals, and very high doses caused more side effects.
What they found
Studies in people
Endurance benefits
Caffeine improved endurance performance by 2 to 4% across dozens of studies using doses of 3 to 6 mg per kg of body mass. Aerobic endurance had the most consistent moderate to large benefits.
Strength and power
Caffeine gave small improvements in muscular strength, muscular endurance, jumping and throwing. Effects on repeated sprints were inconsistent.
Dose and side effects
Doses of 3 to 6 mg per kg improved performance. Very high doses, such as 9 mg per kg, were linked to a high rate of side effects and were not needed for the benefit.
Timing and source
Caffeine was most often taken 60 minutes before exercise. Chewing gum may work faster than capsules.
Individual differences
Responses varied widely between people. Some improved, some did not, and some performed worse. Genetics and habitual caffeine intake may play a role.
Animal and lab studies
Brain effects in rats
In rats, caffeine injected into the brain increased running time before exhaustion, but injections into the body cavity did not. This suggests caffeine works mainly through the central nervous system.
What the authors conclude
“Caffeine has consistently been shown to improve endurance by 2–4% across dozens of studies using doses of 3–6 mg/kg body mass.”
Also in their conclusions
- They conclude that caffeine is an effective aid for many types of exercise, especially endurance, when taken at 3 to 6 mg per kg of body mass.
- They advise athletes to test their individual response to caffeine during practice and to monitor mood and sleep.
- They call for more research on genetics, individual differences, and the effects of caffeine on sleep and anxiety.
How it was done
Caffeine is widely used by athletes and is the most researched sports supplement. The authors wanted to give an expert position on how well it works, at what doses, and who responds.
They reviewed and evaluated the published research on caffeine and exercise performance, including many studies in people and some in animals. They also looked at how genetics, dose, timing and source of caffeine affect the response.
What it can’t tell you
- This is a review of many studies, not a single experiment. It cannot prove that caffeine causes better performance in every person.
- Most studies were short-term and looked at acute effects. They cannot show long-term health outcomes.
- Animal results may not apply to people.
Who paid
- Conflicts
- N.S.G consults for and is on the scientific advisory board of Nutrigenomix, a genetic testing company. T.A.V is on the scientific advisory board for Dymatize Nutrition, a manufacturer of sports supplements; has received research grants related to dietary supplements. B.J.S is on the scientific advisory board for Dymatize Nutrition, a manufacturer of sports supplements. S.M.A has received grants to evaluate the effects of dietary supplements, including caffeine and caffeine-derivatives, serves or has served on scientific advisory boards for sport nutrition companies, has been a paid consultant for a coffee company, and holds patents for an ingredient used in a performance coffee product. J. A is the CEO of the ISSN. The ISSN has received grants from sports supplement companies that sell caffeine-based products. E.T.T earns income as a writer and practitioner within the fitness industry. A.E.S-R has received research grants related to dietary supplements and is a science advisor to Ladder Sport. D.S.K declares that in part, he works for a contract research company that conducts research and human clinical trials for industries including dietary supplements, medical foods, beverages, foods, pharmaceuticals and medical devices. He also sits on the Scientific Advisory Board for Dymatize Nutrition (BellRing Brands) B.I.C is on the scientific advisory board for Dymatize Nutrition, a manufacturer of sports supplements. M.T.N, J. G, N.D.M.J, J.R.S, E.R.G, report no competing interests or conflicts of interest.
- Authors work at
- University of Toronto, Canada; Kennesaw State University, USA; Carrick Institute, USA
The paper
- Title
- International society of sports nutrition position stand: caffeine and exercise performance
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Guest NS, VanDusseldorp TA, Nelson MT, et al (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition. doi:10.1186/s12970-020-00383-4Free full textPubMed 33388079DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error