VITAMINS & SUPPLEMENTS · GUIDE
Supplements for Focus and Concentration in Healthy Adults: What Trials Found
Ingredient by ingredient, what trials and reviews found for focus and attention in healthy adults, how strong the evidence is, and what to check before relying on any product.
Content last updated . This page has not been medically reviewed.
Back to NootropicsThe question and the short answer
Do any supplements improve focus or concentration in healthy adults? Reviews find that one ingredient, caffeine, has fairly consistent short-term evidence on attention tests. For most others the evidence is small, short or mixed. A systematic review of nine ingredients marketed for thinking in healthy adults found a low level of certainty, and said studies were inconsistent, imprecise and often flawed. [1] A separate review of 37 studies in healthy 18 to 35 year olds rated most research as low quality. [2]This page covers healthy adults only. Results for ADHD, mild cognitive impairment or dementia are different questions; see why results do not transfer. It is information only, not advice about what to take.
How to read the table
"Attention" in trials usually means a computer task such as reaction time or accuracy over minutes to hours; see what these tests measure. A better score on a task is not the same as better work or study. Labels: evidence in adequately nourished people (short-term trials in healthy people), promising but limited, mixed, insufficient evidence.| Ingredient | What the source found | Label |
|---|---|---|
| Caffeine | 31 randomized trials (1,455 rested, healthy adults): acute improvement in both reaction time and accuracy. [3] | Evidence in adequately nourished people (short term) |
| L-theanine | 31 trials, healthy and clinical groups pooled: a single dose improved choice reaction time. [4] Reported by authors including a founder of a supplement company. [4] | Promising but limited |
| Caffeine plus L-theanine | A meta-analysis of tea-related trials found small differences, and confidence intervals that often showed uncertainty about direction and size. [5] Some authors are employed by tea companies. [5] | Mixed |
| Bacopa | 9 trials, 518 people, standardized extract for 12 weeks or more: speed of attention improved. [6] A separate review found little evidence outside memory. [7] | Promising but limited |
| Ashwagandha | 20 trials, 1,249 adults: improved attention and processing speed. [8] | Promising but limited |
| Ginseng | 15 trials: no positive effect on attention. [9] A Cochrane review found a lack of convincing evidence in healthy participants. [10] | Insufficient evidence |
| Omega-3 fatty acids | 24 trials in healthy and ADHD groups: no improvement in any cognitive measure; short-term memory improved in people with low omega-3 status. [11] | No good evidence of benefit in the general population |
| Tyrosine | 15 mostly single-session studies: it counteracted drops in working memory under demanding conditions; not tested for ordinary days. [12] | Promising but limited |
| Lion's mane | A 41-person pilot: faster Stroop at 60 minutes, small sample. [13] An 18-person trial found no significant overall effect. [14] | Insufficient evidence |
Caffeine plus L-theanine is covered in Caffeine Plus L-Theanine and Brain Formulas, tyrosine in L-Tyrosine, and lion's mane, rhodiola and ashwagandha in the botanical guides. Proper evidence not found for long-term (months to years) focus benefits in healthy adults: none of the reviews we read reported such outcomes.
Frequently asked questions
What supplement is best for focus?
No supplement has been proven best. Caffeine has the most consistent short-term evidence for attention in rested healthy adults. [3]
Does L-theanine improve concentration?
A meta-analysis reported faster choice reaction time after a single dose, but one author founded a supplement company and other attention outcomes were less clear. [4] See L-theanine.
Do herbal supplements like bacopa work for attention?
A meta-analysis reported faster attention-test speed after 12 weeks or more, with limited evidence beyond that. [6][7]
Does omega-3 help focus in people without ADHD?
A meta-analysis found no cognitive improvement in typically developing groups overall. [11]
Is a focus supplement safe to combine with other products?
That depends on the person and medicines, and a pharmacist can check. Reviews note that people often cannot be sure what is in a product. [1]
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.
Limits and uncertainty
- Several studies above were single sessions or short courses; for example, almost all tyrosine studies tested a single session. [12] One review of healthy 18 to 35 year olds noted that most of its research was of low quality. [2]
- Different extracts and forms are not interchangeable; a result for one extract does not apply to another product.
- Reviews can be influenced by who funds and writes them; disclosures are noted above.
- Sleep, medicines, stress and health conditions often matter more than any supplement; see sleep, food and exercise first and focus and memory research.
Safety and who should ask first
Supplements can interact with medicines, and "natural" does not mean safe. Read how interactions work and questions to ask a clinician or pharmacist. People who are pregnant or breastfeeding, children, older adults, and people with heart, kidney, liver, seizure or anxiety conditions, or who are having surgery, should talk to a clinician or pharmacist first. Product contents vary; see quality testing. Difficulty concentrating that is new or lasting can be a symptom of an underlying condition; see a clinician. For prescription stimulants see why they are not interchangeable with supplements.
References
- Crawford C et al. J Altern Complement Med 2021. Dietary Supplement Ingredients for Optimizing Cognitive Performance Among Healthy Adults: A Systematic Review. Read 2026-10-23.
- Pomeroy DE et al. Nutrients 2020. A Systematic Review of the Effect of Dietary Supplements on Cognitive Performance in Healthy Young Adults and Military Personnel. Read 2026-10-23.
- Kløve K, Petersen A. Psychopharmacology 2025. A systematic review and meta-analysis of the acute effect of caffeine on attention. Read 2026-10-23.
- Gerolymos C et al. Mol Psychiatry 2026. Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials. Read 2026-10-23.
- Payne ER et al. Nutr Rev 2025. Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants. Read 2026-10-23.
- Kongkeaw C et al. J Ethnopharmacol 2014. Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract. Read 2026-10-23.
- Pase MP et al. J Altern Complement Med 2012. The cognitive-enhancing effects of Bacopa monnieri: a systematic review of randomized, controlled human clinical trials. Read 2026-10-23.
- Zhu X et al. Front Pharmacol 2026. Effects of Withania somnifera (L.) Dunal (Ashwagandha) on cognitive and physical function in adults. Read 2026-10-23.
- Zeng M et al. Phytother Res 2024. Effects of Ginseng on Cognitive Function: A Systematic Review and Meta-Analysis. Read 2026-10-23.
- Geng J et al. Cochrane Database Syst Rev 2010. Ginseng for cognition. Read 2026-10-23.
- Cooper RE et al. J Psychopharmacol 2015. Omega-3 polyunsaturated fatty acid supplementation and cognition: A systematic review and meta-analysis. Read 2026-10-23.
- Hase A et al. Pharmacol Biochem Behav 2015. Behavioral and cognitive effects of tyrosine intake in healthy human adults. Read 2026-10-23.
- Docherty S et al. Nutrients 2023. The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults. Read 2026-10-23.
- Surendran G et al. Front Nutr 2025. Acute effects of a standardised extract of Hericium erinaceus (Lion's Mane mushroom) on cognition and mood in healthy younger adults. Read 2026-10-23.
- Bagheri Davisaraei Y et al. Prog Brain Res 2024. Coffee and sleep: Benefits and risks. Read 2026-10-23.