A name that escapes you, a forgotten code, a lesson that will not “stick”: everyone would like to improve their memory. The good news is that the most effective methods are also the simplest, and have been tested in controlled trials. Here is what studies show about sleep, learning techniques, physical activity, diet, stress, hearing and vision, followed by the real, more modest role of nutrients.
Key takeaways
- Sleeping before and after learning, and testing yourself, are among the best-supported ways to remember long term.
- Spacing revision over time produces better results than studying everything in one block the night before.
- Regular physical activity modestly improves cognitive performance after age 50, according to a meta-analysis of 36 trials.
- For nutrients, only specific wordings are authorised, such as “zinc contributes to normal cognitive function”.
How does memory work?
Memory is not a single drawer. It has three stages: encoding, when information is recorded; consolidation, when the brain stabilises it, particularly during sleep; and retrieval, when it is recalled when needed.
Working memory, keeping a few items in mind for seconds, is distinguished from long-term memory, storing knowledge, memories and skills. Each method below acts on one of these stages.
Why is sleep essential for remembering?
Sleep matters before and after learning. A 2021 meta-analysis pooled studies since 1970 on losing a full night's sleep. A sleepless night before learning clearly reduces memorisation ability, with a medium-sized effect (g = 0.62). A sleepless night after learning also harms memory, but less strongly (g = 0.28).
Authors note publication bias and often small studies: the exact effect size is uncertain, but its direction is consistent. Studying all night before an exam is therefore a poor strategy. If sleep is difficult, our article on sleep and melatonin reviews the evidence.
Self-testing: the most underestimated way to improve memory
Rereading notes creates a sense of mastery, but is inefficient learning. Trying to retrieve information without looking strengthens memory much more: this is retrieval practice, or the testing effect.
In a classic study, 180 students read a text four times, or read it once then tried three times to reproduce it from memory. One week later, the self-testing group remembered 61% of the text's ideas versus 40% in the rereading group. Yet the latter group reported greater confidence.
- Close the book, write everything you remember, then check.
- Prefer question-and-answer cards to summaries for rereading.
- Repeat exercises without looking at the solution.
Should revision be spaced out?
Yes. Revisiting a concept several times with time between sessions gives better results than the same study time in one block. This is the spacing effect, one of learning psychology's strongest findings.
A reference meta-analysis identified 839 comparisons from 317 experiments. It also shows that the ideal interval between revisions grows with the time you want to retain information. In practice, revisit a concept the next day, a few days later, then one or two weeks later. Combined with self-testing, this is the principle of revision cards: review forgotten material more often, known material less often.
Does physical activity affect memory?
The hippocampus, a brain structure essential to memory, shrinks with age. In a randomised trial, 120 older adults walked forty minutes three times weekly for a year. Their hippocampus increased around 2% in volume, whereas it fell around 1.4% in controls doing stretches. This gain accompanied better spatial memory results.
A meta-analysis of 36 trials in adults over 50 confirms a favourable exercise effect on cognition: modest (effect size 0.29), but consistent. Sessions of 45 to 60 minutes at least moderate in intensity were associated with the best results; authors recommend combining endurance and strength training.
What should you eat for memory?
No isolated food improves memory. Research instead concerns whole dietary patterns, particularly Mediterranean-style diets: vegetables, fruit, pulses, whole grains, fish, olive oil and nuts.
In a Spanish trial, 447 older people at cardiovascular risk followed a Mediterranean diet enriched with olive oil or nuts, or a low-fat diet, for around four years. Cognitive scores declined in controls but remained stable or slightly improved with the Mediterranean diet. These findings were reanalysed in 2018 after protocol deviations in the main trial.
The picture is not unequivocal. In 2023, a three-year US trial in 604 people found no difference between the MIND diet, a Mediterranean variant, and control diet: both groups improved. A Mediterranean-style diet is consistent with brain health, without being a guarantee.
Does stress impair memorisation?
It depends on timing. A meta-analysis of 113 studies involving 6,216 participants shows that acute stress just before or during learning generally impairs memorisation. Stress immediately after learning can instead strengthen memory if it occurs in the same context.
Learning calmly remains preferable. For more about stress, see our article on stress and ingredients studied for it.
Good hearing and vision: underestimated factors
In 2024, the Lancet dementia commission identified fourteen modifiable risk factors. Its estimates suggest addressing them could prevent or delay nearly half of cases. Hearing loss accounts for around 7% of cases, and newly added uncorrected vision loss around 2%.
A trial tested the idea directly: 977 people aged 70 to 84 with hearing loss received hearing aids and support, or health education sessions. Over three years, overall cognitive decline was identical, but slower in the highest-risk participants. Getting hearing and vision checked remains a simple step.
What about nutrients? What regulations say
The brain needs many nutrients to function. But in Europe, a food supplement may claim an effect only if it is on the authorised claims list, with exact wording and conditions. For cognition, this list is short.
| Nutrient | Authorised wording (EU) | Main condition |
|---|---|---|
| Iron | “Iron contributes to normal cognitive function” | Product is a source of iron |
| Iodine | “Iodine contributes to normal cognitive function” | Product is a source of iodine |
| Zinc | “Zinc contributes to normal cognitive function” | Product is a source of zinc |
| Vitamin B5 | “Pantothenic acid contributes to normal mental performance” | Product is a source of B5 |
| DHA (omega-3) | “Docosahexaenoic acid (DHA) contributes to the maintenance of normal brain function” | Effect obtained with 250mg DHA daily |
| B1, B3, B6, B8, B9, B12, C, magnesium | “… contributes to normal psychological function” | Product is a source of the nutrient |
Being a nutrient “source” means supplying a significant amount. These claims describe a normal role: deficiency harms brain function, not that extra intake improves memory in someone lacking nothing. Iodine, for example, is discussed in our article on iodine deficiency, and magnesium in our comparison of different magnesium forms.
Plants have no authorised health claim. Some have been studied, such as ashwagandha. Huperzine A, a molecule extracted from a Chinese clubmoss-family plant, was mainly studied in Alzheimer's patients: see our feature on huperzine A and its precautions. Choline, used to make acetylcholine, is discussed in our article on its requirements and sources. These substances are sometimes grouped as “nootropics”, a topic we will address separately.
Frequently asked questions
Are brain-training games and apps effective?
They mainly improve performance in the games themselves. A 2016 review examined all studies cited by leading programme publishers. It found extensive evidence of improvement on trained tasks, less for related tasks, and little effect on everyday performance.
Does the method of loci, or “memory palace”, work?
Yes, for remembering lists. In a study published in Neuron, inexperienced volunteers practised thirty minutes daily for forty days. Recall rose from around 26 to 62 words out of 72. Four months later, their score remained more than 22 words above baseline.
Which vitamin should you take for memory?
No vitamin has been shown to improve memory in someone without deficiency. A meta-analysis of sixteen trials involving 6,276 participants found no effect of vitamin B12, alone or with other B vitamins, on cognition in people without deficiency. A confirmed deficiency is different: a doctor should investigate and correct it.
Do alcohol and smoking harm memory?
Excessive alcohol consumption and smoking are among the fourteen dementia risk factors identified by the Lancet commission in 2024. Limiting alcohol and stopping smoking are therefore recommended to preserve cognitive abilities long term.
Why do we have memory blanks on exam day?
Stress during recall interferes with access to information. The stress meta-analysis above shows that stress just before or during recall impairs memory, especially for emotionally charged content. Arriving rested and practising self-tests are two practical approaches.
Memory loss: when should you seek care?
Occasionally forgetting a name or keys is ordinary. Seek care if forgetfulness becomes frequent, worsens, disrupts daily life or worries those around you. A doctor can look for reversible causes such as sleep deprivation, depression, vitamin B12 deficiency, thyroid dysfunction or a medicine's effects.
Conclusion
The best-proven ways to improve memory are free: enough sleep, self-testing rather than rereading, spaced revision and regular movement. A Mediterranean-style diet, calm learning and correcting hearing or vision loss complement this foundation. Nutrients have an underlying role governed by precise claims: they support normal functioning, not replace these habits.
Sources
- Newbury CR et al. (2021). Sleep deprivation and memory: Meta-analytic reviews of studies on sleep deprivation before and after learning. Psychological Bulletin, 147(11), 1215-1240. doi:10.1037/bul0000348
- Roediger HL, Karpicke JD (2006). Test-enhanced learning: taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255. doi:10.1111/j.1467-9280.2006.01693.x
- Cepeda NJ et al. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354-380. doi:10.1037/0033-2909.132.3.354
- Erickson KI et al. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108(7), 3017-3022. doi:10.1073/pnas.1015950108
- Northey JM et al. (2018). Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. British Journal of Sports Medicine, 52(3), 154-160. doi:10.1136/bjsports-2016-096587
- Valls-Pedret C et al. (2015). Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Internal Medicine, 175(7), 1094-1103 (correction published in 2018, 178(12), 1731-1732). doi:10.1001/jamainternmed.2015.1668
- Barnes LL et al. (2023). Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons. New England Journal of Medicine, 389(7), 602-611. doi:10.1056/NEJMoa2302368
- Shields GS et al. (2017). The effects of acute stress on episodic memory: A meta-analysis and integrative review. Psychological Bulletin, 143(6), 636-675. doi:10.1037/bul0000100
- Livingston G et al. (2024). Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet, 404(10452), 572-628. doi:10.1016/S0140-6736(24)01296-0
- Lin FR et al. (2023). Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial. The Lancet, 402(10404), 786-797. doi:10.1016/S0140-6736(23)01406-X
- Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children's development and health. Official Journal of the European Union, L 136, 1-40 (consolidated version of 19 August 2024). EUR-Lex
- Simons DJ et al. (2016). Do "Brain-Training" Programs Work? Psychological Science in the Public Interest, 17(3), 103-186. doi:10.1177/1529100616661983
- Dresler M et al. (2017). Mnemonic Training Reshapes Brain Networks to Support Superior Memory. Neuron, 93(5), 1227-1235.e6. doi:10.1016/j.neuron.2017.02.003
- Markun S et al. (2021). Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression. Nutrients, 13(3), 923. doi:10.3390/nu13030923
Food supplements do not replace a varied, balanced diet or a healthy lifestyle. Ask a healthcare professional for advice if you are taking medication, pregnant or breastfeeding.
