Supplement & Nutrient Encyclopedia

Supplements for focus and memory: what the human evidence shows

13 supplements in our encyclopedia have at least one graded human outcome for focus and memory. Each row shows the strongest one, ranked by grade and then by the number of people studied. A high grade means the research is solid, not that the effect is large: open the row for the size of the effect and the dose tested.

Strongest evidence per supplement

Supplements with graded human evidence for focus and memory, strongest first
SupplementStrongest outcomeGradeStudy
L-theanineAttention (choice reaction time) and acute stressImprovedForm tested: L-theanine (oral)Grade Bmeta-analysis · n = 1,168 · 20262 graded rows for this goal
Creatine monohydrateMemoryImprovedForm tested: creatine monohydrate (all included trials)Grade Bmeta-analysis · n = 492 · 2024
Iodine (potassium iodide, kelp)Information processing and problem solving in moderately deficient schoolchildrenImprovedForm tested: oral iodized oilGrade BRCT · n = 310 · 20063 graded rows for this goal
Turmeric and curcuminGlobal cognitionNo effectForm tested: CurcuminGrade Cmeta-analysis · n = 531 · 2025
TaurineCognitive test scoresNo effectForm tested: taurine, alone or with exercise trainingGrade Cmeta-analysis · n = 402 · 2025
Choline (bitartrate vs alpha-GPC vs phosphatidylcholine)Clinical outcomes with lecithin in dementia and memory complaintsNo effectForm tested: lecithin (phosphatidylcholine)Grade Csystematic-review · n = 376 · 20034 graded rows for this goal
ResveratrolMemory and cognitive performance; moodNo effectForm tested: ResveratrolGrade Cmeta-analysis · n = 226 · 2018
Magnesium L-threonateOverall cognitive performanceImprovedForm tested: magnesium L-threonate (Magtein)Grade CRCT · n = 100 · 2025
SpermidineMemory performance (mnemonic discrimination)No effectForm tested: Spermidine-rich wheat germ extract vs placeboGrade CRCT · n = 100 · 20222 graded rows for this goal
CordycepsCognitive functionNo effectForm tested: Commercial Ophiocordyceps sinensis + Ganoderma lucidum supplement (high or low dose) vs placeboGrade CRCT · n = 96 · 2017
Lion's mane mushroomCognition, stress and mood in healthy young adultsMixedForm tested: Lion's mane vs placeboGrade Dpilot-RCT · n = 41 · 20232 graded rows for this goal
Vitamin B6 (pyridoxine vs P5P)Thinking skills in healthy adults in mid and late life (B vitamins)No effectForm tested: folic acid, vitamin B12, vitamin B6, or combinationsNo effectsystematic-review · n = 27,882 · 2018
Vitamin B12 (methylcobalamin vs cyanocobalamin)Nerve and cognitive function in older adults with low B12No effectForm tested: crystalline vitamin B12No effectRCT · n = 191 · 2015

Grades follow our methodology. A “no effect” grade means good trials found no benefit. Amounts in trials are what was studied, not advice for you.

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Educational information only, not medical advice. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease.