Does coffee have brain benefits?

Answer:

As discussed below, coffee can temporarily increase attention, shorten reaction time, and increase vigilance i.e., the ability to perform during lengthy, boring tasks -- but its effects on short- or long-term memory are mixed.

Be aware that drinking too much coffee, long-term, has been associated with an increased risk of dementia.

Brain benefits of coffee

Coffee contains caffeine, which acts as a central stimulant, although the amount of caffeine varies by coffee type and brand (see table). Caffeine works by blocking the effects of adenosine, a neurotransmitter that slows down brain activity (Huang, Int Rev Neurobiol 2014). (For details about the cognitive effects of green tea, which also contains caffeine, see our Green Tea Review).

Source: FoodData Central, 2024; Starbucks Menu, 2024; Lane, Arbutus Rev 2017

Short-term effects on cognitive function:

Most studies agree that caffeine can improve reaction time, vigilance i.e., the ability to perform during lengthy, boring tasks, and attention i.e., the ability to focus on task-relevant information while ignoring less-relevant information, typically when taken in doses of 100 to 300 mg (which is about the amount in one to three 8-oz cups of coffee). However, when taken in excessive doses (>400 mg), particularly by people who are not sleep-deprived, caffeine may cause anxiety, which may impair cognitive performance (McLellan, Neurosci Biobehav Rev 2016).

There is much less information about the effects of coffee on measures of higher cognitive function – such as executive function – but some preliminary studies have shown short-term benefit. A study in Korea among 21 healthy young adults (average age 31) showed that drinking 160 mL of canned coffee containing 67 mg of caffeine (Let's Be by Lotte Chilsung Beverage) 30 minutes before test taking improved executive function compared to baseline. Interestingly, an analysis of electrical activity in the brain during testing showed that coffee increased the efficiency of connections between different regions of the brain, which may have contributed to its benefits (Kim, Sci Rep 2021). The results of this study are limited by the lack of a placebo group, which is needed to prove benefits.

Similarly, a study in the U.K. among 43 adults (average age 28) who were regular caffeine users showed that drinking about 6.7 fl oz of coffee prepared with 1.8 grams of Nescafe coffee granules containing 50 mg of caffeine improved executive function, as well as planning, creative thinking, and prospective memory (memory for performing or carrying out future-oriented tasks) (based on the Jansari assessment of Executive Functions) compared to drinking the same amount of decaffeinated coffee. However, there was no significant improvement in inhibitory control (based on the Stroop test) (Soar, Appetite 2016).

Short-term effects on memory:

As noted above, the effects of caffeine on both short-term and long-term memory are mixed.

In the Kim study (described above), drinking caffeinated coffee 30 minutes before test taking improved working memory (a type of short-term memory) compared to baseline. However, there were no significant improvements in delayed recall or short-term memory recall (Kim, Sci Rep 2021).

A study in the Netherlands among 21 undergraduate students that were moderate coffee consumers (1 to 4 cups daily) showed that drinking about 9 fl oz of regular coffee or Bulletproof Coffee (a combination of coffee, 1 tbsp of grass-fed butter and 1 tbsp of medium-chain triglyceride oil), both of which contained about 190 mg of caffeine, in the morning 45 minutes before testing did not improve spatial or working memory (types of short-term memory) compared to drinking decaffeinated coffee (Bergauer, Maastricht Student J Psychol Neurosci 2021).

A study in the UK among 59 adults who regularly consumed 2 cups of caffeinated coffee or 3 cups of caffeinated tea daily, 30 of whom were older (average age 68, range: 61 to 80) and the remainder of whom were younger (average age 26, range: 20 to 34), showed that drinking 220 mL (about 7 fl oz) of coffee containing 100 mg of caffeine 30 minutes before testing improved alertness and attention, and decreased mental fatigue and tiredness compared to placebo. However, there were no significant improvements in tests measuring working memory, episodic memory (a form of long-term memory), or language. Interestingly, drinking decaffeinated coffee was also shown to improve alertness compared to placebo, although decaffeinated coffee did not improve other aspects of cognition (Haskell-Ramsay, Nutrients 2018).

Some research suggests that coffee may improve long-term memory, but the effects may depend on the time of day in which it is consumed. A study among undergraduate students from the University of Arizona (average age 19) who were not morning-type individuals showed that drinking one 8-oz cup of coffee containing about 180 mg of caffeine 30 minutes before testing in the early morning (i.e., between 6 and 7 am) improved performance on cued recall, a test that measures explicit memory (a type of long-term memory that can be recalled consciously), compared to drinking decaffeinated coffee. However, it did not improve implicit memory (a type of long-term memory that is unconscious or automatic). Interestingly, drinking caffeinated coffee did not improve long-term memory when consumed 30 minutes before testing in the afternoon (from 2 to 4 pm), when memory tends to be optimal for younger adults, suggesting that coffee may improve long-term memory in adults during their non-optimal time of day, when physiological arousal levels are low (Sherman, Front Psychol 2016).

Effects of other coffee constituents:

Chlorogenic acid, another constituent in coffee, may have some slight cognitive benefit. A study among 34 Japanese adults with mild cognitive impairment showed that taking 553.6 mg of chlorogenic acid twice daily for 12 weeks reduced the number of errors during testing for attention and executive function compared to placebo. However, there was no significant improvement in overall cognitive function based on the Mini-Mental State Examination and Alzheimer’s Disease Assessment Scale — cognitive component (Ochiai, J Alzheimers Dis 2019). In general, daily intake of chlorogenic acid among coffee drinkers is about 500 to 1,000 mg daily (Margreet, J Nutr 2001).

Long-term effects on dementia and cognitive decline

Moderate consumption of caffeinated coffee (1 to 2 cups per day) has been linked with a 19% decreased risk of dementia compared to non-coffee or decaffeinated coffee drinkers, according to a study in the UK of more than 17,000 adults (average age 62); however, drinking more than six cups of caffeinated coffee per day was associated with a 53% increased risk of dementia compared drinking 1 to 2 cups per day (Pham, Nutr Neurosci 2021). Somewhat similarly, another U.S. study (of more than 131,000 adults over 43 years) linked higher daily intake of caffeinated coffee with 18% lower risk of dementia and a 15% lower risk of self-reported cognitive decline compared to not drinking caffeinated coffee, with greatest benefit among those consuming 2 to 3 cups per day and no additional benefit (or harm) among those consuming higher amounts. Interestingly, there was no link between intake of decaffeinated coffee and risk of cognitive decline or dementia (Zhang, JAMA 2026).

Other caffeinated drinks, like energy drinks and sodas, have not been shown to reduce cognitive decline or dementia — although caffeine may boost alertness. One observational study found that drinking more than 1 glass per day of sugar-sweetened soft drinks was linked with a 61% higher risk of dementia compared with non-consumers, and drinking more than 1 glass per day of artificially-sweetened soft drinks was linked with an 82% higher risk of vascular dementia (Kim, J Nutr Health Aging 2025).