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categories: ["enhancement"]categories: ["enhancement"]tags: ["cognition", "enhancement", "pharmacology", "supplements", "evidence", "regulation"]tags: ["cognition", "enhancement", "pharmacology", "supplements", "evidence", "regulation"]summary: "Substances taken to improve cognition in healthy people, a category whose best-evidenced members produce small effects and whose best-selling members produce none."summary: "Substances taken to improve cognition in healthy people, a category whose best-evidenced members produce small effects and whose best-selling members produce none."updated: "2026-07-27"updated: "2026-10-29"humanEvidence: "Meta-analyses in healthy adults find small effects of stimulants and modafinil on laboratory tasks; no trial has shown any nootropic improves a real-world outcome, and the racetams have almost no modern human data."humanEvidence: "Meta-analyses in healthy adults find small effects of stimulants and modafinil on laboratory tasks; no trial has shown any nootropic improves a real-world outcome, and the racetams have almost no modern human data."access: "Caffeine and supplement blends are sold over the counter with no efficacy review; stimulants and modafinil are prescription-only and used off-label; racetams are bought online outside any approval."access: "Caffeine and supplement blends are sold over the counter with no efficacy review; stimulants and modafinil are prescription-only and used off-label; racetams are bought online outside any approval."reversibility: "reversible"reversibility: "reversible"lines 21–27 → 21–276 unchanged lines not shown
{ "label": "Term coined", "value": "1972, Corneliu Giurgea" }, { "label": "Term coined", "value": "1972, Corneliu Giurgea" }, { "label": "Prototype compound", "value": "Piracetam (1964)" }, { "label": "Prototype compound", "value": "Piracetam (1964)" }, { "label": "Best-evidenced agents", "value": "Caffeine, modafinil, stimulants" }, { "label": "Best-evidenced agents", "value": "Caffeine, modafinil, stimulants" }, { "label": "Typical effect size", "value": "Small; d ≈ 0.2–0.3" }, { "label": "Typical effect size", "value": "Small; d ≈ 0.2-0.3" }, { "label": "Regulatory status", "value": "Prescription, supplement, or unapproved" }, { "label": "Regulatory status", "value": "Prescription, supplement, or unapproved" }, { "label": "Main hazard", "value": "Adulterated supplements, dependence" } { "label": "Main hazard", "value": "Adulterated supplements, dependence" } ] ]lines 32–40 → 32–404 unchanged lines not shown
## Origins and definition## Origins and definition The Romanian pharmacologist Corneliu Giurgea synthesised piracetam at the Belgian firm UCB in 1964 and coined "nootropic" — from the Greek for mind-turning — around 1972 to name a class of drug he believed acted on higher integrative brain function without the sedation, stimulation or toxicity of existing psychoactive agents.[^giurgea1973] He proposed five criteria: enhancement of learning and memory; protection of learned behaviour against disruption; protection of the brain against physical or chemical injury; improvement of tonic cortical control mechanisms; and an absence of the usual psychotropic side effects.The Romanian pharmacologist Corneliu Giurgea synthesised piracetam at the Belgian firm UCB in 1964 and coined "nootropic" (from the Greek for mind-turning) around 1972 to name a class of drug he believed acted on higher integrative brain function without the sedation, stimulation or toxicity of existing psychoactive agents.[^giurgea1973] He proposed five criteria: enhancement of learning and memory; protection of learned behaviour against disruption; protection of the brain against physical or chemical injury; improvement of tonic cortical control mechanisms; and an absence of the usual psychotropic side effects. The criteria have not aged well as a research programme. No compound has been shown to meet all five in humans, and piracetam itself, the drug the definition was built around, has never been approved in the United States and has weak evidence for the indications it is licensed for elsewhere. In practice "nootropic" now denotes a market segment rather than a pharmacological class, and much of what is sold under the label would have failed Giurgea's fifth criterion immediately.The criteria have not aged well as a research programme. No compound has been shown to meet all five in humans, and piracetam itself, the drug the definition was built around, has never been approved in the United States and has weak evidence for the indications it is licensed for elsewhere. In practice "nootropic" now names a market segment, not a pharmacological class, and much of what is sold under the label would have failed Giurgea's fifth criterion immediately. ```timeline```timeline[[lines 43–93 → 43–932 unchanged lines not shown
{ "year": "1998", "title": "Modafinil approved", "text": "Modafinil is approved in the United States for narcolepsy, and becomes the most-studied off-label wakefulness agent." }, { "year": "1998", "title": "Modafinil approved", "text": "Modafinil is approved in the United States for narcolepsy, and becomes the most-studied off-label wakefulness agent." }, { "year": "2008", "title": "The Nature poll", "text": "An informal reader survey finds about one in five respondents reporting non-medical use of drugs for focus, memory or concentration, and puts the issue on the scientific agenda." }, { "year": "2008", "title": "The Nature poll", "text": "An informal reader survey finds about one in five respondents reporting non-medical use of drugs for focus, memory or concentration, and puts the issue on the scientific agenda." }, { "year": "2015", "title": "Systematic reviews", "text": "Reviews of modafinil and of prescription stimulants in healthy people converge on small, task-dependent effects rather than general cognitive gain." }, { "year": "2015", "title": "Systematic reviews", "text": "Reviews of modafinil and of prescription stimulants in healthy people converge on small, task-dependent effects rather than general cognitive gain." }, { "year": "2019–2020", "title": "Adulteration documented", "text": "Analyses of commercial cognitive-enhancement supplements find unapproved drugs present, sometimes at doses exceeding pharmaceutical ranges, and regulators issue warning letters." } { "year": "2019-2020", "title": "Adulteration documented", "text": "Analyses of commercial cognitive-enhancement supplements find unapproved drugs present, sometimes at doses exceeding pharmaceutical ranges, and regulators issue warning letters." }]]`````` ## What the evidence supports## What the evidence supports **Caffeine** is the most widely used psychoactive substance in the world and the best-established agent in the category. It reliably improves alertness, vigilance and reaction time, especially under fatigue. A long-standing dispute concerns how much of the benefit in habitual users is restoration from overnight withdrawal rather than enhancement above an unmedicated baseline; the withdrawal-reversal effect is real, though evidence in non-consumers suggests it does not explain the whole effect.**Caffeine** is the most widely used psychoactive substance in the world and the best-established agent in the category. It reliably improves alertness, vigilance and reaction time, especially under fatigue. A long-standing dispute concerns how much of the benefit in habitual users is restoration from overnight withdrawal rather than enhancement above an unmedicated baseline; the withdrawal-reversal effect is real, though evidence in non-consumers suggests it does not explain the whole effect. Its separate reputation as a longevity aid rests on cohort associations discussed under [[coffee-and-aging]]. **Modafinil** is licensed for narcolepsy and shift-work sleep disorder and used off-label for wakefulness. In sleep-deprived people its effects are clear. In rested healthy volunteers, a systematic review by Battleday and Brem found consistent improvement on complex tasks involving attention, executive function and learning, and little or no effect on simple tasks or on mood.[^battleday2015] An earlier review by Repantis and colleagues had reached a more cautious conclusion, finding limited evidence for enhancement outside sleep deprivation.[^repantis2010] Both note that longer and more demanding tasks show effects that brief tests miss.**Modafinil** is licensed for narcolepsy and shift-work sleep disorder and used off-label for wakefulness. In sleep-deprived people its effects are clear. In rested healthy volunteers, a systematic review by Battleday and Brem found consistent improvement on complex tasks involving attention, executive function and learning, and little or no effect on simple tasks or on mood.[^battleday2015] An earlier review by Repantis and colleagues had reached a more cautious conclusion, finding limited evidence for enhancement outside sleep deprivation.[^repantis2010] Both note that longer and more demanding tasks show effects that brief tests miss. **Prescription stimulants** — methylphenidate and amphetamine salts — have been studied extensively in healthy adults. A meta-analysis by Ilieva, Hook and Farah found small effects on inhibitory control, working memory and delayed episodic memory, on the order of a fifth to a third of a standard deviation.[^ilieva2015] Subjective reports of improvement consistently exceed measured performance, which is the finding most relevant to how these drugs are actually used. Effects are larger in low performers than in high performers, an inversion of the usual assumption about who benefits from enhancement.**Prescription stimulants**, chiefly methylphenidate and amphetamine salts, have been studied extensively in healthy adults. A meta-analysis by Ilieva, Hook and Farah found small effects on inhibitory control, working memory and delayed episodic memory, on the order of a fifth to a third of a standard deviation.[^ilieva2015] Subjective reports of improvement consistently exceed measured performance, and this is the finding most relevant to how the drugs are used in practice. Effects are larger in low performers than in high performers, the reverse of the usual assumption about who benefits from enhancement. > [!stat] The size of the effect> [!stat] The size of the effect> The largest replicated cognitive gains from a nootropic in rested healthy adults are comparable to the effect of a night of adequate sleep or of moderate aerobic exercise, both of which are free and have no dependence liability. Any evaluation of the class has to start from that comparison.> The largest replicated cognitive gains from a nootropic in rested healthy adults are comparable to the effect of a night of adequate sleep or of moderate aerobic exercise, both of which are free and carry no dependence liability. That comparison is the baseline for judging the class. ## What the evidence does not support## What the evidence does not support **The racetams.** Piracetam, aniracetam, oxiracetam and phenylpiracetam are the compounds most closely associated with the word "nootropic". A Cochrane review of piracetam for dementia and cognitive impairment concluded the evidence was insufficient to support its use.[^flicker2001] Controlled data in healthy young adults are sparse, small and mostly old. The newer racetams have essentially no published human trials at all.**The racetams.** Piracetam, aniracetam, oxiracetam and phenylpiracetam are the compounds most closely associated with the word "nootropic". A Cochrane review of piracetam for dementia and cognitive impairment concluded the evidence was insufficient to support its use.[^flicker2001] Controlled data in healthy young adults are sparse, small and mostly old. The newer racetams have essentially no published human trials. **Herbal and supplement agents.** Ginkgo biloba was tested in a large, long randomised prevention trial and did not reduce the incidence of dementia.[^dekosky2008] Bacopa monnieri, Rhodiola, lion's mane and citicoline have small trials with mixed results and heterogeneous preparations. Effects reported in this literature are rarely distinguishable from expectancy, and the placebo response for a subjectively assessed cognitive outcome is large.**Herbal and supplement agents.** Ginkgo biloba was tested in a large, long randomised prevention trial and did not reduce the incidence of dementia.[^dekosky2008] Bacopa monnieri, Rhodiola, lion's mane and citicoline have small trials with mixed results and heterogeneous preparations. Effects reported in this literature are rarely distinguishable from expectancy, and the placebo response for a subjectively assessed cognitive outcome is large. [[magnesium-l-threonate|Magnesium L-threonate]], sold for memory and sleep after a 2010 rat study reported raised brain magnesium and better learning, illustrates the pattern: every placebo-controlled trial of its effects on cognition or sleep has been funded by a company selling the ingredient, and the largest of the compound alone, in 100 adults aged 18 to 45, found a small advantage on one cognitive composite after six weeks and none on Raven's matrices.[^lopresti2025] **Proprietary blends.** Products combining a dozen ingredients at undisclosed doses cannot be evaluated. Where they have been analysed chemically, results have been poor: Cohen and colleagues found several unapproved drugs, including omberacetam, phenibut, vinpocetine, picamilon and aniracetam, present in commercially sold cognitive-enhancement supplements, sometimes at doses above those used pharmaceutically.[^cohen2020] Phenibut in particular carries dependence and withdrawal risk that consumers buying a "focus" supplement have no reason to expect.**Proprietary blends.** Products combining a dozen ingredients at undisclosed doses cannot be evaluated. Chemical analyses of them have turned up poor results: Cohen and colleagues found several unapproved drugs, including omberacetam, phenibut, vinpocetine, picamilon and aniracetam, present in commercially sold cognitive-enhancement supplements, sometimes at doses above those used pharmaceutically.[^cohen2020] Phenibut in particular carries dependence and withdrawal risk that consumers buying a "focus" supplement have no reason to expect. > [!caution] Regulatory gap> [!caution] Regulatory gap> In the United States, [[dietary-supplements]] are not reviewed for efficacy before sale, and enforcement is post-market. A compound withdrawn from a supplement after a warning letter can reappear under a different name. Consumers of this market are not protected by the evidence standards that apply to the prescription drugs in the same category.> In the United States, [[dietary-supplements]] are not reviewed for efficacy before sale, and enforcement is post-market. A compound withdrawn from a supplement after a warning letter can reappear under a different name. Consumers of this market are not protected by the evidence standards that apply to the prescription drugs in the same category. ## Mechanisms and why they are hard to establish## Mechanisms and why they are hard to establish The agents with real effects act on arousal and catecholamine signalling. Caffeine antagonises adenosine receptors; stimulants increase synaptic dopamine and noradrenaline; modafinil's action is less well characterised but involves dopamine transporter inhibition among other effects. None of these mechanisms is specific to cognition. They shift arousal and motivation, and cognitive performance changes as a consequence, which is why effects follow an inverted-U with dose and baseline state.The agents with real effects act on arousal and catecholamine signalling. Caffeine antagonises adenosine receptors; stimulants increase synaptic dopamine and noradrenaline; modafinil's action is less well characterised but involves dopamine transporter inhibition among other effects. None of these mechanisms is specific to cognition. They shift arousal and motivation, and cognitive performance changes as a consequence; this is why effects follow an inverted-U with dose and baseline state. Wakefulness agents add a further complication: suppressing sleepiness is not the same as reducing the need for sleep, and the debt continues to accumulate while the drug masks it, an asymmetry examined in [[sleep-reduction]]. That structure has three consequences. Gains at one point on the curve are losses at another, so a drug that helps a tired person can impair a rested one. Improvement on one function often costs another: stimulants can narrow attention in a way that helps rote tasks and hurts creative or divergent ones. And a drug that raises confidence more than performance will be judged effective by the person taking it regardless of what it does. Careful studies of putative cognitive enhancers therefore separate objective measures from self-report, and the two frequently diverge.Wakefulness agents add a further complication. Suppressing sleepiness does not reduce the need for sleep, and the debt keeps accumulating while the drug masks it, an asymmetry examined in [[sleep-reduction]]. The arousal-based mechanism has three consequences. Gains at one point on the curve are losses at another, so a drug that helps a tired person can impair a rested one. Improvement on one function often costs another: stimulants can narrow attention in a way that helps rote tasks and hurts creative or divergent ones. And a drug that raises confidence more than performance will be judged effective by the person taking it regardless of what it does. Careful studies of putative cognitive enhancers therefore separate objective measures from self-report, and the two frequently diverge. ## Use, ethics and policy## Use, ethics and policy Non-medical stimulant use is concentrated in academic and competitive settings, where the pressure is positional. The ethical structure is the one described in [[enhancement-arms-race]]: where enough peers use a drug, declining ceases to be a neutral choice. Bioethicists writing in support of open access — the position developed in [[bioethics-of-enhancement]] and defended by [[julian-savulescu]] among others, and grounded in the autonomy claim of [[morphological-freedom]] — argue that a safe and effective cognitive drug should be treated like caffeine. Critics reply that the conditional has not been satisfied, since none of the drugs in question have been assessed for long-term safety in healthy users, and that prescription diversion is not a considered policy. The unregulated end of the market overlaps with the self-experimentation described in [[biohacking]], where dosing decisions are made from forum consensus.Non-medical stimulant use is concentrated in academic and competitive settings, where the pressure is positional. The ethical structure is the one described in [[enhancement-arms-race]]: where enough peers use a drug, declining ceases to be a neutral choice. Some bioethicists support open access, a position developed in [[bioethics-of-enhancement]], defended by [[julian-savulescu]] among others, and grounded in the autonomy claim of [[morphological-freedom]]. They argue that a safe and effective cognitive drug should be treated like caffeine. Critics reply that the condition has not been met, since none of the drugs in question have been assessed for long-term safety in healthy users, and that prescription diversion is not a considered policy. The unregulated end of the market overlaps with the self-experimentation described in [[biohacking]], where dosing decisions are made from forum consensus. Sport treats the question differently. Stimulants are prohibited in competition and modafinil is on the World Anti-Doping Agency list, with the therapeutic-use exemption process drawing an operational line between treatment and enhancement; see [[enhancement-in-sport]] and, for the anticipated genetic version, [[gene-doping]]. Military organisations have used modafinil and, historically, amphetamine for sustained operations, which is the clearest institutional endorsement of pharmacological cognitive enhancement anywhere and the setting in which that collective pressure is least deniable.Sport treats the question differently. Stimulants are prohibited in competition and modafinil is on the World Anti-Doping Agency list, with the therapeutic-use exemption process drawing an operational line between treatment and enhancement; see [[enhancement-in-sport]] and, for the anticipated genetic version, [[gene-doping]]. Military organisations have used modafinil and, historically, amphetamine for sustained operations. That use is the clearest institutional endorsement of pharmacological cognitive enhancement anywhere, and the military is the setting where the collective pressure is hardest to deny. The wider context is set by [[human-enhancement]] and by the alternatives: [[non-invasive-neuromodulation]] devices marketed for cognition have their own replication problems, the psychedelic microdosing taken up under [[psychedelic-therapy]] reports benefits that self-blinded designs do not confirm, [[intelligence-amplification]] argues that external tools have delivered far more than any drug, and the genetic route described in [[genetic-enhancement-of-intelligence]] is constrained by polygenicity. Interest has also moved toward compounds that target [[hallmarks-of-aging|ageing biology]] on the hypothesis that preserving cognition is easier than augmenting it, a framing shared with [[healthspan]] research and pursued in [[exercise-and-aging]], which remains the best-evidenced intervention for cognitive function across the lifespan.The wider context is set by [[human-enhancement]] and by the alternatives: [[non-invasive-neuromodulation]] devices marketed for cognition have their own replication problems, the psychedelic microdosing taken up under [[psychedelic-therapy]] reports benefits that self-blinded designs do not confirm, [[intelligence-amplification]] argues that external tools have delivered far more than any drug, and the genetic route described in [[genetic-enhancement-of-intelligence]] is constrained by polygenicity. Interest has also moved toward compounds that target [[hallmarks-of-aging|ageing biology]] on the hypothesis that preserving cognition is easier than augmenting it, a framing shared with [[healthspan]] research and pursued in [[exercise-and-aging]], which remains the best-evidenced intervention for cognitive function across the lifespan. ## Open questions## Open questions No nootropic has been shown to improve a real-world outcome — a grade, a diagnosis rate, a piece of work — in a controlled trial in healthy adults. Laboratory tasks are the entire evidence base, and their relation to consequential performance is weak. Long-term safety in non-patients is similarly unstudied: the trials that exist run for weeks, and the use pattern that matters runs for years.No nootropic has been shown in a controlled trial in healthy adults to improve a real-world outcome such as a grade, a diagnosis rate or a piece of work. Laboratory tasks are the entire evidence base, and their relation to consequential performance is weak. Long-term safety in non-patients is similarly unstudied: the trials that exist run for weeks, and the use pattern that matters runs for years. Whether any pharmacological agent can raise cognitive capacity, as opposed to shifting arousal along a curve the brain already occupies, is the question Giurgea posed and it remains open. Sixty years after piracetam, no compound has clearly answered it in the affirmative.Giurgea's question was whether any pharmacological agent can raise cognitive capacity, as opposed to shifting arousal along a curve the brain already occupies. It remains open: sixty years after piracetam, no compound has clearly answered it in the affirmative. ## See also## See also lines 109–112 → 109–11315 unchanged lines not shown
[^flicker2001]: `paper` Flicker, L. and Grimley Evans, J. "Piracetam for dementia or cognitive impairment." *Cochrane Database of Systematic Reviews*, 2001. {The trials pooled were in patients with dementia or cognitive impairment; the review says nothing about piracetam in healthy adults, who are most of the market.}[^flicker2001]: `paper` Flicker, L. and Grimley Evans, J. "Piracetam for dementia or cognitive impairment." *Cochrane Database of Systematic Reviews*, 2001. {The trials pooled were in patients with dementia or cognitive impairment; the review says nothing about piracetam in healthy adults, who are most of the market.}[^dekosky2008]: `paper` DeKosky, S. T. et al. "Ginkgo biloba for prevention of dementia: a randomized controlled trial." *JAMA*, 2008. {A long prevention trial in older adults with dementia incidence as the endpoint; it did not test short-term cognitive performance in healthy younger users.}[^dekosky2008]: `paper` DeKosky, S. T. et al. "Ginkgo biloba for prevention of dementia: a randomized controlled trial." *JAMA*, 2008. {A long prevention trial in older adults with dementia incidence as the endpoint; it did not test short-term cognitive performance in healthy younger users.}[^cohen2020]: `paper` Cohen, P. A. et al. "Five unapproved drugs found in cognitive enhancement supplements." *Neurology: Clinical Practice*, 2020. {A chemical analysis of products bought off the shelf, not a study in people; it establishes what was in the bottles tested, not what the ingredients do.}[^cohen2020]: `paper` Cohen, P. A. et al. "Five unapproved drugs found in cognitive enhancement supplements." *Neurology: Clinical Practice*, 2020. {A chemical analysis of products bought off the shelf, not a study in people; it establishes what was in the bottles tested, not what the ingredients do.}[^lopresti2025]: `paper` Lopresti, A.L. and Smith, S.J. "The effects of magnesium L-threonate (Magtein) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial." *Frontiers in Nutrition*, 2025 (published online January 2026). {Funded by Threotech, which supplied the product; participants were adults under 46 with self-reported poor sleep, not older adults.} removed, struck through added, underlinedLine numbers count the serialised markdown of each revision, frontmatter included.
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