Skip to content
Winnowleaf home

Supplements for Memory and Brain Fog: Lion's Mane, Creatine and What the Trials Show

For memory and brain fog, check the common causes first: poor sleep, an underactive thyroid, low vitamin B12, menopause and long COVID. Among supplements, creatine gave a small memory gain in 16 trials (grade B), and a daily multivitamin gave adults over 60 a small memory gain in the COSMOS study (grade B). Lion's mane rests on a few small trials (grade C), and ginkgo and omega-3 did not protect memory in large trials.

Published How we grade evidenceEditorial policy

Brain fog is not a diagnosis. It is a catch-all for slow thinking, poor focus and forgetting words or names, and it often has a cause a doctor can find. Memory supplements are sold on big promises, but most rest on small trials. Here is what to check first, and what the trials show for lion's mane, creatine, multivitamins, omega-3, ginkgo, B vitamins, bacopa and saffron.

The short version

  • Check the common causes first: poor sleep, an underactive thyroid, low vitamin B12, menopause and long COVID can all cloud thinking (Cao 2025; Chaker 2025; Patel 2025; Maki 2022; Gorenshtein 2024).
  • Creatine gave a small memory gain in pooled trials, though it did not improve overall thinking. Grade B (Xu 2024).
  • A daily multivitamin gave adults over 60 a small memory gain across three substudies of the COSMOS trial. Grade B (Vyas 2024).
  • Lion's mane rests on a few small trials with mixed results. Grade C (Mori 2009; Docherty 2023).
  • Ginkgo and omega-3 did not protect memory in large trials of older adults. Grade B for no clear benefit (DeKosky 2008; Sydenham 2012).
SupplementWhat trials foundSize of effectGrade
CreatineBetter memory, attention and speed; no change in overall thinkingSmall (16 trials)B
MultivitaminBetter memory and overall thinking in adults over 60Small (3 COSMOS substudies)B
BacopaFaster attentionSmall (437 people pooled)B
SaffronBetter thinking scores in mild cognitive impairment or Alzheimer's4 trialsC
Lion's maneMixed; one small trial in mild cognitive impairment30 peopleC
GinkgoNo fewer dementia cases; no memory gain in healthy people3,069 peopleB (no benefit)
Omega-3No difference in older adults3 trialsB (no benefit)

What causes brain fog?

Often something you can test for or change. About 45% to 48% of people with hypothyroidism (an underactive thyroid) have thinking problems such as memory loss and difficulty concentrating (Chaker 2025). Low vitamin B12 can cause fatigue and brain fog (Patel 2025); our vitamin B12 guide covers who runs low. Many women notice changes in thinking during the menopause transition (Maki 2022). Long COVID can bring confusion, short-term memory loss and trouble concentrating (Gorenshtein 2024). And sleep loss slows thinking: in a 2025 analysis of 79 studies, it harmed working memory and other planning skills (Cao 2025). Medicines can play a part too, so ask your pharmacist to review yours.

Does creatine help memory and brain fog?

Grade B for a small memory gain. In a 2024 pooled analysis of 16 trials (492 adults aged about 21 to 76), creatine monohydrate improved memory, attention time and processing speed, but not overall thinking or executive function, the planning and switching skills. The reviewers rated the memory evidence moderate certainty (Xu 2024). An earlier analysis of 8 trials in healthy people found a small memory gain that was larger in adults aged 66 to 76 (Prokopidis 2023). Our creatine page grades cognitive improvement D; we grade memory B because these two pooled analyses agree on a small memory effect. See our creatine page and creatine guide.

Does a multivitamin help memory?

Grade B for a small gain in older adults. The COSMOS study randomly assigned adults over 60 to a daily multivitamin or a placebo. Pooling its three thinking substudies (573, 2,158 and 2,472 people), the multivitamin gave a small benefit in overall thinking and in episodic memory, the memory for recent events; the authors put the overall effect at about 2 years less thinking decline (Vyas 2024). In the largest substudy, scores on one online word-recall test improved at 1 year and over 3 years; other tests did not change (Yeung 2023). The effect is small, and it was tested in adults over 60, not in younger people with brain fog. See our multivitamin page.

Does lion's mane help memory?

Grade C. The trials are few and small. In 30 Japanese adults aged 50 to 80 with mild cognitive impairment (early memory problems), twelve 250 mg tablets a day (96% dried mushroom powder) for 16 weeks raised thinking scores more than placebo, but the scores fell again within 4 weeks of stopping (Mori 2009). In another 12-week placebo-controlled trial, only one of three memory and thinking tests improved (Saitsu 2019). In 41 healthy adults aged 18 to 45, one dose made them quicker on one test, but 28 days of use brought no clear gains on the thinking tests, and the authors urged caution (Docherty 2023). Reported side effects include stomach discomfort, headache and allergic reactions (Menon 2025).

Does omega-3 or fish oil help memory?

Grade B for no clear benefit in older adults. In a Cochrane review of 3 trials, omega-3 made no difference to a standard memory and thinking test after 24 or 40 months in the 2 trials that measured it (3,221 people), and other memory tests showed no benefit (Sydenham 2012). See our omega-3 page.

Does ginkgo help memory?

Grade B for no clear benefit. In the largest trial, 3,069 adults aged 75 or older took ginkgo or placebo for a median of about 6 years; dementia was no less common on ginkgo (3.3 against 2.9 cases per 100 person-years) (DeKosky 2008). In healthy people, a pooled analysis found effects close to zero for memory, attention and planning skills (Laws 2012). Our ginkgo page grades memory C from 3 small studies; we grade it B for no clear benefit because of these larger analyses. Ginkgo can raise bleeding risk with blood thinners (NCCIH). See our ginkgo page.

Do B vitamins help memory?

Grade B for little or no effect in healthy adults. A Cochrane review of 14 trials (27,882 people, mostly in their 60s and 70s) found B vitamins probably have little or no effect on overall thinking (Rutjes 2018). The exception may be people with mild cognitive impairment and high homocysteine, a blood marker that B vitamins lower. In 271 people over 70, folic acid, B12 and B6 for 2 years slowed brain shrinkage on scans, by 53% in those with homocysteine above 13 µmol/L ( Grade C) (Smith 2010). Ask for a B12 test before you supplement. See our vitamin B12 page and folic acid page.

Do bacopa or saffron help memory?

Grade B for bacopa, mainly for speed. In a review of 9 trials, the pooled data from 437 people showed bacopa extract shortened the time on a test of attention and switching and quickened reaction time (Kongkeaw 2014). See our bacopa page.

Grade C for saffron in people with memory problems. In 4 trials in mild cognitive impairment or Alzheimer's disease, saffron improved thinking scores more than placebo and showed no significant difference from standard dementia medicine, with no serious side effects reported, but the trials were few and small (Ayati 2020). See our saffron page.

What about NAD+ boosters like NMN?

Grade D for no clear benefit. In a pilot trial of 20 older adults with mild cognitive impairment, nicotinamide riboside, a vitamin B3 compound sold to raise NAD+, was well tolerated but did not change thinking over 10 weeks (Orr 2024). We found no trial of NMN for memory in people, only animal studies, so we give no amounts.

What we'd skip

  • "Nootropic" blends and huperzine A products. In 22 products sold for brain health with huperzine A, 73% listed ingredients that weren't found, 73% contained compounds not on the label, including stimulants, and only 2 had huperzine A within 10% of the stated amount (Crawford 2020). Our quality guide shows how to check a product.
  • Ginkgo to protect memory. No fewer dementia cases in 3,069 older adults (DeKosky 2008).
  • Omega-3 capsules for memory if you are healthy. No difference in 3 trials (Sydenham 2012).
  • Racetams and other drug-like "smart pills". One such drug, noopept, was among the compounds found in the brain-health products above (Crawford 2020); we give no amounts for them.

Safety and interactions

  • Ginkgo with a blood thinner such as warfarin: ask your prescriber or pharmacist first (NCCIH).
  • Creatine raised serum creatinine, a kidney blood test, by about 0.13 mg/dL in 19 trials, with no significant change in eGFR, the main measure of kidney filtering, in 8 trials (Tsiaras 2026). Tell your doctor you take it so the test is read correctly; our creatine guide covers its safety.
  • Folic acid above 1,000 mcg a day can hide a B12 deficiency. Upper limit for adults: 1,000 mcg of folic acid a day, because more can mask B12 deficiency; take more only with blood tests or your clinician's advice (NIH ODS; check your stack).
  • Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist. If you are pregnant, breastfeeding, or under 18, ask a clinician.

When to see a doctor

  • Memory problems that are getting worse, or that family members notice, such as getting lost in familiar places or repeating questions: ask for an assessment rather than trying supplements first.
  • Sudden confusion, trouble speaking, weakness on one side or a severe headache: call emergency services.
  • Brain fog with tiredness, weight gain or feeling cold, or with numbness or tingling: ask for thyroid and B12 tests (Chaker 2025; Patel 2025).
  • Brain fog that started after a new medicine: ask the prescriber; don't stop it on your own.
  • Pregnant, breastfeeding or under 18: ask a clinician before you start any supplement.

FAQ

What is the best supplement for memory? None works dramatically. Creatine gave a small memory gain in 16 trials (grade B), and a daily multivitamin gave adults over 60 a small memory gain in the COSMOS study (grade B). Check sleep, thyroid and B12 first.

Does lion's mane help brain fog? The evidence is thin: one 16-week trial of 30 people with mild cognitive impairment found better thinking scores that faded after stopping, and a pilot in 41 young adults found few gains (grade C).

Does creatine help brain fog? It may help memory a little: in 16 trials of adults, memory, attention and processing speed improved slightly, but overall thinking did not (grade B).

Do multivitamins help memory? In adults over 60 in the COSMOS study, taking a multivitamin every day led to a small improvement in memory and overall thinking, which the authors put at about 2 years less decline (grade B).

Does fish oil help memory? Not in older adults without dementia: a Cochrane review of 3 trials found no difference from placebo (grade B for no clear benefit).

Sources

  1. Cao Y, et al. The impairments of sleep loss on core executive functions: General and task-specific effects. Sleep Med Rev. 2025. PubMed 40946426 · doi:10.1016/j.smrv.2025.102163
  2. Chaker L, et al. Hypothyroidism: A Review. JAMA. 2025. PubMed 40900603 · doi:10.1001/jama.2025.13559
  3. Patel H, et al. Vitamin B12 Deficiency: Common Questions and Answers. Am Fam Physician. 2025. PubMed 40961307
  4. Maki PM, et al. Brain fog in menopause: a health-care professional's guide for decision-making and counseling on cognition. Climacteric. 2022. PubMed 36178170 · doi:10.1080/13697137.2022.2122792
  5. Gorenshtein A, et al. Intervention modalities for brain fog caused by long-COVID: systematic review of the literature. Neurol Sci. 2024. PubMed 38695969 · doi:10.1007/s10072-024-07566-w
  6. Xu C, et al. The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis. Front Nutr. 2024. PubMed 39070254 · doi:10.3389/fnut.2024.1424972
  7. Vyas CM, et al. Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS. Am J Clin Nutr. 2024. PubMed 38244989 · doi:10.1016/j.ajcnut.2023.12.011
  8. Mori K, et al. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytother Res. 2009. PubMed 18844328 · doi:10.1002/ptr.2634
  9. Docherty S, et al. The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study. Nutrients. 2023. PubMed 38004235 · doi:10.3390/nu15224842
  10. DeKosky ST, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA. 2008. PubMed 19017911 · doi:10.1001/jama.2008.683
  11. Sydenham E, et al. Omega 3 fatty acid for the prevention of cognitive decline and dementia. Cochrane Database Syst Rev. 2012. PubMed 22696350 · doi:10.1002/14651858.CD005379.pub3
  12. Prokopidis K, et al. Effects of creatine supplementation on memory in healthy individuals: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2023. PubMed 35984306 · doi:10.1093/nutrit/nuac064
  13. Yeung LK, et al. Multivitamin Supplementation Improves Memory in Older Adults: A Randomized Clinical Trial. Am J Clin Nutr. 2023. PubMed 37244291 · doi:10.1016/j.ajcnut.2023.05.011
  14. Saitsu Y, et al. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomed Res. 2019. PubMed 31413233 · doi:10.2220/biomedres.40.125
  15. Menon A, et al. Benefits, side effects, and uses of Hericium erinaceus as a supplement: a systematic review. Front Nutr. 2025. PubMed 40959699 · doi:10.3389/fnut.2025.1641246
  16. Laws KR, et al. Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis. Hum Psychopharmacol. 2012. PubMed 23001963 · doi:10.1002/hup.2259
  17. Rutjes AW, et al. Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life. Cochrane Database Syst Rev. 2018. PubMed 30556597 · doi:10.1002/14651858.CD011906.pub2
  18. Smith AD, et al. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. PLoS One. 2010. PubMed 20838622 · doi:10.1371/journal.pone.0012244
  19. Kongkeaw C, et al. Meta-analysis of randomized controlled trials on cognitive effects of Bacopa monnieri extract. J Ethnopharmacol. 2014. PubMed 24252493 · doi:10.1016/j.jep.2013.11.008
  20. Ayati Z, et al. Saffron for mild cognitive impairment and dementia: a systematic review and meta-analysis of randomised clinical trials. BMC Complement Med Ther. 2020. PubMed 33167948 · doi:10.1186/s12906-020-03102-3
  21. Orr ME, et al. A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment. Geroscience. 2024. PubMed 37994989 · doi:10.1007/s11357-023-00999-9
  22. Crawford C, et al. The scoop on brain health dietary supplement products containing huperzine A. Clin Toxicol (Phila). 2020. PubMed 31990212 · doi:10.1080/15563650.2020.1713337
  23. Tsiaras A, et al. The Effect of Creatine Supplementation on Kidney Function: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Ren Nutr. 2026. PubMed 42035842 · doi:10.1053/j.jrn.2026.04.010