VITAMINS & SUPPLEMENTS · GUIDE
Nootropic Evidence Summary Table by Ingredient and Outcome
A one-page table of what reviews and health agencies say about ginkgo, bacopa, citicoline, theanine, omega-3, B vitamins and more for memory and focus, with evidence labels and links.
Content last updated . This page has not been medically reviewed.
Back to NootropicsQuick answer
For most ingredients sold for memory and focus, the sources we read describe the evidence as limited, mixed or inconclusive. Several large reviews of older adults found no convincing benefit. No row below is advice, and findings in one group of people do not carry over to another.
How to read the labels
Each row has an evidence label. No good evidence of benefit means the sources we read say trials did not show benefit for that outcome in that group. Mixed means trials or reviews disagree. Promising but limited means some positive results from small, short or low-quality studies. Insufficient evidence means the source says there is not enough evidence to judge. A label describes the studies, not your own result. Short lab tasks such as reaction time are not the same as everyday memory.Evidence table
| Ingredient | Group and outcome studied | What the source found | Label |
|---|---|---|---|
| Ginkgo | Adults 75 and older, normal thinking or mild impairment; dementia (GEM trial, over 3,000 people, median 6 years) | No difference between ginkgo and placebo in dementia or Alzheimer's rates. [1] | No good evidence of benefit |
| Ginkgo | Healthy people, cognitive performance | NCCIH says it is uncertain whether ginkgo influences performance, and much of the research is low quality. [1] | Insufficient evidence |
| Ginkgo | People with Alzheimer's disease or mild impairment | Meta-analyses of EGb-761 extract reported some improvement, but a NCCIH digest says small, inconsistent studies need confirming. [2] | Mixed |
| Bacopa | Pooled randomized trials of standardized extract taken 12 weeks or longer (9 studies, 518 people) | A 2014 meta-analysis found shorter Trail B time and faster choice reaction time, and said a large head-to-head trial is still needed. [3] | Promising but limited |
| Bacopa | Clinical data reviewed in 2021 | The review said limited studies exist to establish memory-enhancing effects. [4] | Insufficient evidence |
| Citicoline | People with mild cognitive impairment, Alzheimer's or post-stroke dementia (7 studies) | A 2023 meta-analysis found improved cognitive status, but overall study quality was poor with risk of bias. [5] | Promising but limited |
| L-theanine, with or without caffeine; tea | Healthy participants, 50 trials in a 2025 review | Small-to-moderate differences within the first two hours for some tasks, with confidence intervals that often showed uncertainty. [6] | Mixed |
| Lion's mane (Hericium erinaceus) | One 12-week placebo-controlled trial of fruiting-body supplements | Only one of three tests (the MMSE) showed a significant change. [7] | Insufficient evidence |
| Asian ginseng | Middle-aged and young adults | A small amount of research suggested better abstract thinking and attention in middle-aged but not young adults; memory benefit seemed to depend on adding ginkgo. [8] | Promising but limited |
| Ashwagandha | Cognitive function | NCCIH says there is not enough evidence to determine whether it helps. [9] | Insufficient evidence |
| Rhodiola | Any health-related purpose, including cognition | NCCIH says it has not learned enough to say whether rhodiola is useful. [10] | Insufficient evidence |
| Omega-3 supplements | Older people without dementia | One review of 3 trials with over 3,500 people found no benefit on cognitive functioning. [2] | No good evidence of benefit |
| Vitamin E (alpha-tocopherol) | Mild cognitive impairment or Alzheimer's | A 2017 Cochrane review found no evidence it prevents progression or improves cognition. [2] | No good evidence of benefit |
| B vitamins (B12, B6, folic acid) | Adults 50 and older | Short-term studies found no help; a meta-analysis of 95 studies over 12 months suggests B vitamins may be linked with slower decline. [2] | Mixed |
| Curcumin | Alzheimer's disease and healthy aging | Clinical trials are few and inconsistent. [2] | Insufficient evidence |
Ingredients not summarized here
For phosphatidylserine, alpha-GPC, creatine, magnesium L-threonate, huperzine A, tyrosine, vinpocetine, picamilon, racetams, noopept and prescription stimulants, this table makes no evidence statement because we did not read enough sources for this page. Proper evidence not found on this page for those rows; we searched NCCIH and PubMed review abstracts only. The ingredient pages carry their own evidence sections. Follow the links in the ingredient A to Z.Reading beyond the table
Outcome-by-outcome summaries are in nootropic evidence by outcome and do nootropics work?. Why results differ between healthy adults and clinical groups is in why results do not transfer. Ingredient pages: Ginkgo, Bacopa, citicoline, L-theanine, omega-3 and B-vitamin trials.Frequently asked questions
Which brain supplement has the best evidence?
None is declared a clear winner in the sources we read. Ratings differ by ingredient, group and outcome, and several (ginkgo, omega-3, vitamin E) were found not to help in older-adult dementia or cognition trials. [1][2]
Does the table mean an ingredient is safe?
No. Lack of evidence of harm is not proof of safety, and several rows carry bleeding or medicine-interaction notes. [1]
Why do some reviews disagree?
Studies use different extracts, groups, lengths and tests. For ginkgo, a large trial found no benefit for dementia prevention while smaller reviews in people with impairment saw some benefit. [2]
Are results in healthy young adults the same as in older adults?
Not necessarily. NCCIH describes cognitive findings for ginseng differing between middle-aged and young adults. [8]
Where do I read about a specific ingredient?
Use the ingredient A to Z, which links to each guide.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask first
NCCIH says ginkgo may increase the risk of bleeding with anticoagulant drugs such as warfarin, may interact with other drugs, and may be unsafe in pregnancy. [1] The FDA lists warfarin, ginkgo, aspirin and vitamin E as products that can each thin the blood and may raise bleeding risk together, and says a health professional may ask people to stop supplements two or three weeks before surgery. [11] Do not start or stop anything on this page's account. Memory change, ADHD or dementia concerns need a clinician first, and nobody should change a prescribed medicine on their own. NIA says to check with a doctor before trying any supplement that promises to prevent Alzheimer's. [12] For product quality see quality testing and for interactions medication interactions.
References
- NCCIH, Ginkgo. Read 2026-10-23.
- NCCIH, Dietary Supplements and Cognitive Function, Dementia, and Alzheimer's Disease: What the Science Says, Clinical Digest, July 2022. Read 2026-10-23.
- Kongkeaw C, et al. Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract. J Ethnopharmacol, 2014. Read 2026-10-23.
- The effectiveness of Bacopa monnieri (Linn.) Wettst. as a nootropic, neuroprotective, or antidepressant supplement: analysis of the available clinical data. 2021. Read 2026-10-23.
- Is Citicoline Effective in Preventing and Slowing Down Dementia? A Systematic Review and a Meta-Analysis. 2023. Read 2026-10-23.
- Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. 2025. Read 2026-10-23.
- Improvement of cognitive functions by oral intake of Hericium erinaceus. 2019. Read 2026-10-23.
- NCCIH, Asian Ginseng. Read 2026-10-23.
- NCCIH, Ashwagandha. Read 2026-10-23.
- NCCIH, Rhodiola. Read 2026-10-23.
- U.S. Food and Drug Administration (FDA), Mixing Medications and Dietary Supplements Can Endanger Your Health. Read 2026-10-23.
- National Institute on Aging (NIA), Preventing Alzheimer's Disease: What Do We Know?. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.