Coffee without
the crash.

When scientists pooled the controlled studies, caffeine and L-theanine together showed a real benefit for alertness and for accurately switching your attention between tasks in the first couple of hours.

Camfield et al., systematic review and meta-analysis of 11 randomized controlled trials.

L-theanine, the amino acid in green tea, was shown to boost the brain's alpha waves, which the researchers describe as relaxing the mind without making you drowsy.

Prof. Anna C. Nobre, cognitive neuroscientist, University of Oxford / Yale.

In a controlled trial, pairing L-theanine with caffeine sped up reaction time and improved accuracy, while lowering tired and headache ratings, a different profile than caffeine on its own.

Haskell et al., Brain, Performance and Nutrition Research Centre.

Researchers found L-theanine plus a modest amount of caffeine helps to focus attention during a demanding cognitive task, improving accuracy and alertness while reducing tiredness.

Giesbrecht et al.

In a controlled study, caffeine with L-theanine improved both speed and accuracy on attention-switching tasks and made people less susceptible to distraction.

Owen et al.

L-tyrosine is a building block for the brain chemicals you burn through under pressure. Reviewers found it can enhance cognitive performance, particularly in short-term stressful and cognitively demanding situations.

Jongkees et al., review of tyrosine in healthy and clinical populations.

In a 4-week randomized trial, L-theanine on its own lowered stress and anxiety scores and improved verbal fluency and executive-function performance in healthy adults.

Hidese et al., National Center of Neurology and Psychiatry, Japan.

Lion's mane is a slow-burn ingredient. In a controlled trial, adults taking it daily improved on a cognitive test at weeks 8, 12 and 16, and the researchers noted the benefit built up over time and faded after they stopped. That is why we treat it as daily, cumulative support, not an instant hit.

Mori et al.