The term “nootropics” was coined by Romanian psychologist Corneliu Giurgea in 1972 to describe substances that specifically improve cortical/subcortical cognitive function with extremely low toxicity. The term has been generalized to mean “any substance claimed to improve cognition,” including nutritional supplements, herbal extracts, prescription drugs, and recreational drugs.
## Cognitive Substances with Stronger Evidence
**Caffeine + L-Theanine**: the most thoroughly studied cognitive enhancement combination to date. Caffeine improves alertness and focus by antagonizing adenosine receptors (blocking sleep-drive signals); L-theanine (naturally present in green tea) moderates caffeine’s anxiety and palpitation side effects by increasing alpha brain waves and GABA activity. The combination (200mg caffeine + 100mg L-theanine) consistently shows improvements in attention, working memory, and reaction speed across multiple double-blind RCTs — superior to caffeine alone.
**Omega-3 fatty acids (DHA/EPA)**: DHA (docosahexaenoic acid) is an important component of neuronal cell membranes, comprising approximately 40% of brain fat content. Long-term deficiency is associated with cognitive decline and depression. For elderly individuals with existing cognitive impairment (mild cognitive impairment), DHA supplementation has some improvement evidence; for healthy young adults seeking short-term cognitive enhancement, evidence is weak. Recommend obtaining from food sources (fatty fish: salmon, sardines, herring) 2-3 times per week.
**Creatine**: typically known as a muscle supplement, but the brain’s high ATP demands make creatine’s neuroprotective and cognitive functions an active research area. Studies show creatine supplementation can improve working memory and reasoning under sleep deprivation or high cognitive demand, with stronger effects in vegetarians (creatine primarily comes from meat; vegetarians have lower baseline levels).
## Common “Traps” and Caveats
Clinical evidence for large numbers of “brain-boosting” products (ginkgo biloba extract, phosphatidylserine, various “brain formulas”) is essentially zero in healthy adults, or existing evidence quality is very low (small samples, no controls, severe publication bias). Modafinil is popular among students but is only approved for narcolepsy; long-term effects are unknown; it is a controlled substance in China.
See [Brain Science Overview](https://sunqi.org/brain-science-overview-en/) and [Examine.com supplement database](https://examine.com/).
