Best Nootropics, Ranked by Clinical Evidence
Every nootropic in the SuppIndex database, ranked by its evidence score — a 0–100 grade of the indexed human research. No sponsorships, no affiliate ordering: the ranking is the database, re-sorted live.
Last reviewed July 16, 2026 · Reviewed by the SuppIndex research team (editorial policy) · Educational only — not medical advice.
The 30-second answer
- #1 Caffeine Anhydrous — 90/100 (Strong). Typical dose: 3–6 mg/kg 30–60 min pre-exercise.
- #2 Alpha-GPC — 78/100 (Strong). Typical dose: 300–600mg/day.
- #3 L-Theanine — 72/100 (Moderate). Typical dose: 100–200mg for focus (with caffeine); 200–400mg for relaxation/sleep.
- Verdict: start with the top of the table — evidence density drops quickly further down, where scores reflect emerging rather than established research.
The full ranking
#1Caffeine Anhydrous
Methylxanthine alkaloid; non-selective adenosine A1/A2A receptor antagonist; raises cAMP, catecholamine release, and Ca²⁺ sensitivity in muscle.
- Dose
- 3–6 mg/kg 30–60 min pre-exercise
- Timing
- 30–60 min pre-exercise/task; avoid within 6 h of bed
- Studies
- 1 indexed
90/100#2Alpha-GPC
Highly bioavailable choline donor that elevates brain acetylcholine levels, supporting memory, learning, and muscular power output via enhanced neuromuscular junction signaling.
- Dose
- 300–600mg/day
- Timing
- 30–60 min pre-workout or morning for cognition
- Studies
- 2 indexed
78/100#3L-Theanine
A non-proteinogenic amino acid analog of glutamate that crosses the BBB, promoting alpha-wave brain activity and modulating inhibitory neurotransmitter balance.
- Dose
- 100–200mg for focus (with caffeine); 200–400mg for relaxation/sleep
- Timing
- 30 minutes before desired effect. For sleep, 1 hour before bed.
- Studies
- 3 indexed
72/100#4Lion's Mane
Medicinal mushroom containing bioactive compounds (hericenones, erinacines) that cross the blood-brain barrier and stimulate endogenous NGF production, supporting neurogenesis and cognitive function.
- Dose
- 1000–3000mg/day
- Timing
- Morning or split AM/PM
- Studies
- 2 indexed
72/100#5Anserine
Randomized trials and one meta-analysis of histidine‑containing dipeptides (including anserine) show improvement in delayed recall measures (Wechsler Memory Scale delayed recall) and some benefit on global clinical dementia rating or MMSE in subgroups. One small exercise trial using chicken breast extract rich in anserine/carnosine altered blood buffering but did not improve sprint performance.
- Dose
- 500 mg–1 g/day (studied doses range: 500 mg anserine alone; combinations providing ~750 mg anserine + 250 mg carnosine; 1.0 g mixed formula (anserine:carnosine 3:1))
- Timing
- Not established
- Studies
- 5 indexed
69/100#6Theacrine
1,3,7,9-tetramethyluric acid; weak adenosine A1/A2A antagonist and dopamine D1/D2 modulator; longer half-life (~16 h) than caffeine.
- Dose
- 100–300 mg/day
- Timing
- Morning or pre-exercise
- Studies
- 1 indexed
62/100#7Infinergy Dicaffeine Malate
Caffeine + malic acid ionic complex; releases caffeine at near-identical rate to anhydrous in pharmacokinetic studies, with malate entering the TCA cycle.
- Dose
- 200–400 mg Infinergy per pre-workout
- Timing
- 30 min pre-exercise
- Studies
- 1 indexed
60/100#8Huperzine A
Sesquiterpene alkaloid; reversible AChE inhibitor that increases synaptic acetylcholine; also has NMDA-antagonist and neuroprotective properties.
- Dose
- 100–200 mcg/day
- Timing
- Morning; cycle 5 days on / 2 off
- Studies
- 1 indexed
56/100#9Acetyl-L-Carnitine
Systematic reviews and guideline documents identify a large trial literature but show inconsistent effects. Older meta-analyses suggested possible benefit on some dementia clinical global measures, but later and larger trials failed to confirm robust cognitive benefit. Reviews of neuropathy and hepatic encephalopathy report mixed evidence; some meta-analyses examined small trials and the safety signal for chemotherapy-induced peripheral neuropathy prompted recommendations against its use in that setting.
- Dose
- Not established from the provided abstracts
- Timing
- Not established from the provided abstracts
- Studies
- 5 indexed
46/100#10Bacopa Monnieri
Bacosides (triterpenoid saponins) are the main active constituents. Human RCTs generally use ~300 mg/day of 50–55% bacoside extract for 8–12 weeks and report modest improvements in memory recall and information processing.
- Dose
- 300–450 mg/day standardised extract
- Timing
- Daily, with a meal (fat improves saponin absorption); effects build over 8–12 weeks
- Studies
- 0 indexed
45/100#11Citicoline
Citicoline breaks down to choline and cytidine (converted to uridine), both of which cross the blood-brain barrier and feed phospholipid synthesis. European clinical use in stroke recovery is established; evidence in healthy young adults is thinner but includes positive attention studies at 250–500 mg.
- Dose
- 250–500 mg/day
- Timing
- Morning or pre-task; daily
- Studies
- 0 indexed
45/100#12Phenylethylamine (NeuroPEA)
Endogenous trace amine acting at TAAR1 and as a substrate releaser of dopamine and noradrenaline; oral half-life of minutes due to MAO-B degradation.
- Dose
- 250–500 mg pre-workout
- Timing
- 15–20 min pre-exercise
- Studies
- 1 indexed
40/100#13Phosphatidylserine
PS is a structural component of the inner leaflet of cell membranes, important for receptor function and signalling. Trials in age-related cognitive complaints (100–300 mg/day) show modest memory benefits; exercise studies show blunted cortisol responses at higher doses (600–800 mg), with mixed performance outcomes.
- Dose
- 100–300 mg/day (cognitive); 600–800 mg/day in exercise-cortisol studies
- Timing
- Daily; with meals
- Studies
- 0 indexed
40/100#14Ginkgo Biloba
The 24/6 standardisation (flavone glycosides + ginkgolides/bilobalide) defines pharmaceutical-grade extracts. The largest RCTs (e.g. GEM, GuidAge) found no prevention of dementia in healthy elderly, while some trials in mild cognitive impairment show small symptomatic benefits.
- Dose
- 120–240 mg/day
- Timing
- Daily, divided doses
- Studies
- 0 indexed
35/100
Scores and doses come from the live ingredient database — each entry links to the full evidence review with cited studies.
Frequently asked questions
What is the most evidence-backed nootropic?
Of the 14 nootropics indexed on SuppIndex, Caffeine Anhydrous currently has the strongest evidence (90/100, Strong), followed by Alpha-GPC (78/100). Rankings update as new research is indexed.
How is this ranking calculated?
Rankings come directly from SuppIndex evidence scores — a 0–100 grade built from the quality, quantity and consistency of indexed human research plus dose-response and safety data. No placement is paid or editorialized; the list re-ranks automatically when scores change. See our methodology on the About page.
Can I stack nootropics together?
Some combinations are well-studied (caffeine + l-theanine is the classic pairing); others have little combined-use research. Check the interaction notes on each ingredient page and consult a clinician if you take medication.
Educational content only — not medical advice. See our methodology & editorial policy.