Caffeine and Cognition: How Much Do YOU Need?

We probably know that caffeine can improve various aspects of cognitive performance, but what’s less often explored or considered is if/how the amount of caffeine one regularly consumes impacts how much caffeine is necessary to provide these pro-cognitive benefits.

For example, in undergraduate students who only consumed a median of 42.5mg/day caffeine, 200mg and 400mg caffeine improved vigilance and executive control of visual attention with 200mg seeming to be more “optimal” than 400mg (1).

But in a study on undergraduate students who consumed a median of 592.3mg/day caffeine, caffeine only enhanced vigilance and executive control of visual attention at 400mg, not at 200mg (2).

So, if you consume a decent amount of caffeine daily, you may well need higher doses to get acute cognitive/performance benefits, even non-physical/athletic benefits. But there is some mixed research on the topic, and different methodologies and measures of cognition may partially explain some differences or seeming conflicts in the research I would think.

Some more research on various doses of caffeine for people with various caffeine intake (3):

Warburton (1995) examined the effects of 0, 75, and 150 mg of caffeine on attentional, verbal memory, nonverbal working memory, and problem-solving speed and accuracy in 18 men who were regular coffee drinkers (no more than 3 cups/day). Caffeine improved speed and accuracy on attentional tests (visual information processing) in a dose-dependent manner. Similar to the data of Foreman et al. (1989), there was no effect of caffeine on immediate verbal recall; however there was a dose-related effect of caffeine on delayed verbal recall. Caffeine also significantly improved the accuracy, but not the speed, of problem solving. Rogers et al. (1995) found significant improvement in reaction time with 70 mg of caffeine compared to placebo. Similarly, Lorist and Snel (1997) found that caffeine at 3 mg/kg (210 mg for a 70 kg person) given to habitual users improved reaction time and decreased false alarm rates in selective attention tasks. Streufert et al. (1997) evaluated the effects of 400 mg of caffeine added to regular caffeine consumption in moderate to heavy caffeine users (400–1,000 mg/day) and found faster responses to incoming information.

How about caffeine with theanine? Did any of these studies specify the daily/regular caffeine intake of the subjects? Because many of these studies noted synergistic cognitive benefits with pretty low doses of caffeine.

Subjects in one study consumed an average of 9.6 servings of caffeine per week, and noted benefits with only 50mg caffeine and 100mg theanine (4). It is worth noting that the group that received only 50mg caffeine (with no theanine) noted benefits, but the combination was superior, indicating synergistic effects on aspects of memory and attention. I’m not entirely certain how much caffeine is in a “serving” of caffeine though. Is it black tea (28-46mg per cup), tea or instant coffee (55-65mg per cup), or brewed coffee (107-151mg per cup) (6)? So this 9.6 servings per week could, in theory, be anywhere from 38mg/day (9.6 servings per week at 26mg per serving) to 207mg/day (9.6 servings per weeks at 151mg per serving). I suppose it could even be higher in theory if a “serving” of caffeine could have included something like a large coffee from a coffee shop, but who knows really.

Another study had subjects who consumed an average of 173mg/day caffeine (SD 86.8mg), and found that 40mg caffeine and 97mg theanine “helps to focus attention during a demanding cognitive task” (5). This study did not have a group use caffeine without theanine, only the combination and placebo.

So, in summary, if you consume a lot of caffeine regularly, you may need more caffeine to get cognitive benefits than if you consumer very little caffeine regularly, and if you consume very little caffeine regularly, the “optimal” dose of caffeine may be lower than it is if you consume a lot of caffeine regularly. That’s a pretty logical thing to expect, no? But that’s not to say that lower doses of caffeine won’t work for regular caffeine consumers, as there are studies showing that they can. And, as most of us know, theanine goes very well with caffeine.

1: Caffeine modulates attention network function - PubMed
2: Acute caffeine consumption enhances the executive control of visual attention in habitual consumers - PubMed
3: Doses and Delivery Mechanisms - Caffeine for the Sustainment of Mental Task Performance - NCBI Bookshelf
4: The combined effects of L-theanine and caffeine on cognitive performance and mood - PubMed
5: The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness - PubMed


So it sounds like the more you consume the more you build up a tolerance.


As with most supps.

I’m a prime example. I need 300mg-400mg per day. It’s due to my abuse of caffeine over 10 years. I cycle off for a month every 4 months, and that does help.


I was in the hospital for close to a week a few months ago, no caffeine at all for that time and a few days on either end of it, and I gotta say, a cup of coffee hit me harder after that then it has in a while. Within a month or two I was back up to 300-400mg/day, and it takes at least 150-200mg to really “feel” it (although if I add noots I can get away with 100mg at a time easily), with 250-300mg being a good acute dose for maximal effects for me. But I’m able to stick to NMT 400mg/day, and I’m not concerned with that being an excessive dose health wise at all, but it is nice to take a break every so often so I can get more out of less every so often.

I do like adding a bit of theacrine to my caffeine though. Very lackluster as a substitute for caffeine, but a nice addition to it IMO.


For me I find I respond best to lower doses of caffeine, 100-200 mg, despite being a regular caffeine drinker.
My bench mark tends to be playing rainbow 6 though, which does incentivise more careful playstyles, so that is likely biasing the results a bit.

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