Graded on controlled human evidence. A millisecond figure appears only when a primary paper reports one. Entries marked
as summaries are drafted from the established literature, and their full study review is in progress.
A
Consistent effects across many controlled human trials, including in the target population.
B
Several controlled human trials agree, with clear caveats about who and when.
C
Small, mixed or condition-specific human evidence.
D
Mostly animal, cell or anecdotal evidence. Human data thin or absent.
A
Caffeine
Stimulant. Established. Effect seen: rested and fatigued.
Studies reviewed
Reaction-time effect
−11 to −18 ms mean PVT reaction time at 1 and 3 mg/kg in FPS players vs water (290.8 → 279.8 / 273.0 ms).
Mechanism
Blocks adenosine A1 and A2A receptors, removing the brake that builds up with time awake. Indirectly increases dopamine and noradrenaline signalling.
Verdict
The best-supported acute performance compound in esports. In habitual users part of the "boost" is reversal of overnight withdrawal, so the real gain over a non-user is smaller than it feels.
Esports data
Yes. Controlled trials in FPS players show faster PVT responses and better aim-trainer scores (Rogers 2024; Wu 2024, n = 9).
Risks
Sleep disruption when taken late, anxiety and tremor at high intakes, tolerance, withdrawal headaches and sluggishness.
Legal status
Unrestricted. On the WADA monitoring programme, not the prohibited list.
Amino acid. Plausible. Effect seen: rested and fatigued.
Studies reviewed
Reaction-time effect
−27.8 ms response time to visual targets vs placebo (fMRI study, n = 9 men).
Mechanism
Tea amino acid that crosses the blood-brain barrier. Proposed to modulate glutamate and GABA signalling and increase resting alpha-band EEG activity linked to relaxed attention.
Verdict
Modest alone, with small samples. Its strongest evidence is as a partner to caffeine. Increasingly available in fast, discreet pouch formats.
Esports data
No published trial of L-theanine alone in esports players yet.
Risks
Very well tolerated in trials. May add to the effect of blood-pressure or sedative medication.
Stimulant. Contradictory. Effect seen: rested and fatigued.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Agonist at nicotinic acetylcholine receptors (α4β2, α7). Triggers release of acetylcholine, dopamine and noradrenaline within minutes of oral or inhaled absorption.
Verdict
A 41-study meta-analysis found genuine acute gains in fine motor, attention and memory domains in non-deprived users. Later reviews call the effects inconsistent. In regular users much of the benefit is relief from withdrawal.
Esports data
No controlled esports trial yet.
Risks
Highly addictive. Dependence turns the benefit into a baseline you need to reach normal. Raises heart rate and blood pressure. Not appropriate for non-users or under-18s.
Legal status
Age-restricted. Pouch rules differ between countries and are changing.
Metabolic. Plausible. Effect seen: mainly fatigued or stressed.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Raises brain phosphocreatine, a rapid energy buffer for neurons under metabolic stress.
Verdict
Cognitive benefits look clearest under sleep deprivation, in vegetarians and in older adults. Effects in rested young adults are small or absent. Builds up over days, so it cannot act in the moment.
Esports data
No published esports trial.
Risks
Well tolerated. Water retention and stomach upset in some people.
Legal status
Unrestricted food supplement.
C
L-tyrosine
Amino acid. Plausible. Effect seen: mainly fatigued or stressed.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Precursor of dopamine and noradrenaline. The theory is that it tops up catecholamine supply when demand is high.
Verdict
Evidence points to protection of working memory and cognitive control during acute stressors (cold, multitasking, sleep loss), not improvement in rested people.
Esports data
None published.
Risks
Generally well tolerated. Interacts with MAO inhibitors and thyroid medication.
Legal status
Unrestricted food supplement.
C
Citicoline
Cholinergic. Plausible. Effect seen: chronic use only.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Supplies choline and cytidine for acetylcholine and neuronal membrane synthesis.
Verdict
A small number of trials in healthy adults report attention benefits after weeks of use. Too few to call.
Esports data
None published.
Risks
Well tolerated in trials. Headache and stomach upset reported.
Legal status
Food supplement in the UK and EU.
D
Alpha-GPC
Cholinergic. Speculative. Effect seen: unclear.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Highly bioavailable choline source, proposed to support acetylcholine synthesis.
Verdict
Clinical data come mostly from dementia populations. Very little controlled data on reaction time or attention in healthy young adults.
Esports data
None published.
Risks
Generally well tolerated. One large observational study linked it to higher stroke risk; causation not established.
Legal status
Food supplement.
C
Rhodiola rosea
Botanical. Contradictory. Effect seen: mainly fatigued or stressed.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Adaptogen claimed to blunt stress-hormone responses and mental fatigue.
Verdict
Some trials report less mental fatigue under stress, but studies are small, extract quality varies and reviews rate the evidence as low quality.
Esports data
None published.
Risks
Generally well tolerated. Product quality and contents vary between brands.
Legal status
Traditional herbal registration or supplement depending on product.
C
Bacopa monnieri
Botanical. Plausible. Effect seen: chronic use only.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Ayurvedic herb whose bacosides are proposed to support synaptic signalling and antioxidant defences.
Verdict
Meta-analyses suggest modest gains in memory and attention speed after around 12 weeks. No acute effect, so irrelevant to match-day performance.
Esports data
None published.
Risks
Stomach upset and fatigue are common early on.
Legal status
Food supplement.
B
Modafinil
Prescription. Contradictory. Effect seen: mainly fatigued or stressed.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Weak dopamine reuptake inhibitor that also engages orexin and histamine wake systems.
Verdict
Reliably restores performance in sleep-deprived people. In rested healthy adults effects are small and inconsistent, with some benefit on long, complex tasks.
Esports data
Covered by esports anti-doping rules. ESL introduced testing in 2015 after a professional publicly admitted stimulant use at an event.
Prescription-only in the UK. Prohibited in competition by WADA.
B
Amphetamine & methylphenidate
Prescription. Contradictory. Effect seen: rested and fatigued.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Increase synaptic dopamine and noradrenaline by blocking reuptake (methylphenidate) or driving release (amphetamine).
Verdict
In healthy people, meta-analysis finds only small effects on inhibitory control and memory. Users often feel far more enhanced than they measure. Arousal effects follow an inverted U, so more is not better.
Esports data
Banned under esports anti-doping rules without a therapeutic use exemption.
Risks
Dependence, cardiovascular strain, sleep loss, anxiety and rebound.
Legal status
Controlled drugs. Prohibited in competition by WADA.
D
Nootropic peptides
Peptide. Speculative. Effect seen: unclear.
Summary
Reaction-time effect
No verified millisecond figure in healthy adults.
Mechanism
Compounds such as Semax and Selank (ACTH and tuftsin analogues) are claimed to raise BDNF and modulate stress and attention systems.
Verdict
Mechanisms come largely from rodent work, and human clinical studies are few and mostly in patient groups. No credible evidence on reaction time or gaming in healthy adults.
Esports data
None published.
Risks
Unknown long-term safety. Grey-market products are unregulated and their contents are unverified.