The same could be said for L-theanine, an amino acid found in green tea that is added to some supplements because of its association with better concentration and lower stress. No large, rigorous trials have shown that L-theanine improves cognition, said Dr. Pieter Cohen, an associate professor of medicine at Harvard Medical School. Some studies have found links between better cognitive performance and high consumption of dietary choline, an essential nutrient that occurs naturally in fish, eggs, poultry and dairy and is added to some cognitive enhancing supplements. But no thorough studies have proven that supplemental choline itself directly leads to cognitive benefits. In a study published in 2021, for example, Dr. Cohen and his colleagues tested 10 over-the-counter dietary supplements that were said to contain certain forms of the pharmaceutical drug piracetam.

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Persons: Pieter Cohen, “, ”, Craig Hopp, Cohen, . Cohen Organizations: Harvard Medical School, National Center, Integrative Locations: United States