Mild cognitive impairment (MCI)
Supplements studied for mild cognitive impairment (MCI).
Overview
Evidence for mild cognitive impairment supplements is mostly limited across 15 studies. Lion's Mane Mushroom powder three times daily for 16 weeks improved thinking skills in Japanese adults aged 50 to 80 compared with placebo, though benefits decreased within four weeks of stopping. Olive Oil added to the diet for several months showed small memory test improvements in small trials.
Melatonin, Nicotinamide Riboside, and Nattokinase have insufficient or negative evidence. The heatmap and evidence reviews below compare these findings.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Melatonin | ★★★★★ | Low |
| Theanine | ★★★★★ | Low |
| Resveratrol | ★★★★★ | Low |
| Olive Oil | ★★★★★ | Low |
| Nattokinase | ★★★★★ | Low |
| Lion's Mane Mushroom | ★★★★★ | Low |
| Ashwagandha | ★★★★★ | Low |
| Vitamin K | ★★★★★ | Low |
| Vitamin D | ★★★★★ | Very Low / None |
| Nicotinamide Riboside | ★★★★★ | Very Low / None |
| L-Tryptophan | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
11 supplements for and rated at least stars. All purchase bands. No minimum star filter.
MelatoninView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- There is not enough evidence to determine if melatonin has any benefit for mild cognitive impairment.
Browse 5 studies·1 meta-analysis
MetaComparative Efficacy, Tolerability, and Acceptability of Donanemab, Lecanemab, Aducanumab, Melatonin, and Aerobic Exercise for a Short Time on Cognitive Function in Mild Cognitive Impairment and Mild Alzheimer's Disease: A Systematic Review and Network Meta-Analysis2024n=4,599
A network meta-analysis of 10 RCTs (4,599 MCI/mild AD patients) found melatonin significantly more effective than donanemab, lecanemab, aducanumab, and placebo for cognitive function, with excellent tolerability.
- Effect
- Benefit
- Population
- MCI patients
- Participants
- 4,599
Systematic reviewPharmacological and non-pharmacological interventions to enhance sleep in mild cognitive impairment and mild Alzheimer's disease: A systematic review2021n=10
A systematic review of 18 interventional studies in MCI/mild AD found adapted CBT-I, suvorexant, and melatonin each significantly improved sleep parameters, with melatonin reducing sleep latency in two small studies.
- Effect
- Benefit
- Population
- MCI patients
- Participants
- 10
- Avg age
- ~74
RCTDietary Melatonin Therapy Alleviates the Lamina Cribrosa Damages in Patients with Mild Cognitive Impairments: A Double-Blinded, Randomized Controlled Study2020n=40
In 40 patients with mild cognitive impairment, double-blind melatonin treatment reduced thinning of the lamina cribrosa compared with placebo, a structural ocular marker linked to neurodegeneration.
- Effect
- Benefit
- Population
- MCI patients
- Participants
- 40
RCTEffects of a diet integration with an oily emulsion of DHA-phospholipids containing melatonin and tryptophan in elderly patients suffering from mild cognitive impairment2012n=11
In 25 elderly adults with MCI, 12 weeks of DHA-phospholipid emulsion with melatonin and tryptophan did not significantly improve cognition versus placebo.
- Effect
- No Benefit
- Duration
- 12 weeks
- Population
- Older adults
- Participants
- 11
- Avg age
- ~86±6
Controlled trialMelatonin effects on sleep, mood, and cognition in elderly with mild cognitive impairment1998
In 10 elderly adults with mild cognitive impairment, melatonin 6 mg improved rest-activity rhythm and reduced sleep onset latency but did not significantly increase total sleep time.
- Effect
- Benefit
- Duration
- 10 days
- Dose
- 6 mg
- Population
- Older adults
AshwagandhaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if ashwagandha helps with mild cognitive impairment.
- One small study found that taking 250 mg daily of a specific ashwagandha extract for 2 months modestly improved memory and overall thinking compared to placebo.
- The study was small and had some factors that might have affected the results.
Browse 1 study
RCTEffect of ashwagandha (Withania somnifera) extract with Sominone (Somin-On™) to improve memory in adults with mild cognitive impairment: A randomized, double-blind, placebo-controlled study2025n=40
In 40 adults with mild cognitive impairment over 60 days, ashwagandha extract with Sominone improved MoCA and MMSE memory scores versus placebo.
- Effect
- Benefit
- Duration
- 60 days
- Dose
- 250 mg/day
- Population
- Adults
- Participants
- 40
Lion's Mane MushroomView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- In one study of Japanese adults aged 50 to 80 with mild memory problems, taking lion's mane mushroom powder three times a day for 16 weeks improved thinking skills compared with a placebo.
- However, benefits decreased when treatment stopped, with thinking scores dropping within four weeks.
- Other small studies have shown mixed results, with some improvements in thinking and mood, while others found little or no effect.
- Research in animals and lab studies suggests lion's mane may protect brain cells and encourage new growth, but more research is needed to confirm how well it works in people.
Browse 1 study
RCTImproving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial2009n=30
In 30 Japanese adults with mild cognitive impairment, 3 g/day Yamabushitake for 16 weeks improved HDS-R cognitive scores versus placebo.
- Effect
- Benefit
- Duration
- 16 weeks
- Dose
- 3 g/day
- Population
- Adults
- Participants
- 30
NattokinaseView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- There is not enough evidence to determine if nattokinase has any benefit for mild cognitive impairment.
Browse 1 study
RCTEfficacy and Safety of Lactobacillus Plantarum C29-Fermented Soybean (DW2009) in Individuals with Mild Cognitive Impairment: A 12-Week, Multi-Center, Randomized, Double-Blind, Placebo-Controlled Clinical Trial2019n=50
In 100 adults with mild cognitive impairment, 800 mg/day L. plantarum-fermented soybean (DW2009) for 12 weeks improved attention-domain cognition and raised serum BDNF vs placebo.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 800 mg/day
- Population
- Adults
- Participants
- 50
- Ages
- 55–85
Olive OilView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if taking olive oil by mouth helps with memory or thinking problems.
- In small studies, older adults with mild memory problems who added extra virgin olive oil to their diet for several months showed small improvements on one memory test and some brain scans suggesting better brain function.
- Another study found that both extra virgin and refined olive oil helped with memory and behavior, but only extra virgin olive oil helped brain health on scans.
- These studies were small and did not have comparison groups, so more research is needed.
Browse 2 studies
RCTExtra-Virgin Olive Oil Enhances the Blood-Brain Barrier Function in Mild Cognitive Impairment: A Randomized Controlled Trial2022n=26
An RCT of 25 adults with mild cognitive impairment found 6 months of extra-virgin olive oil improved dementia ratings, reduced blood-brain barrier permeability, and enhanced brain connectivity versus refined olive oil.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 1200 mg/kg
- Population
- MCI patients
- Participants
- 26
RCTA Randomized Clinical Trial of Greek High Phenolic Early Harvest Extra Virgin Olive Oil in Mild Cognitive Impairment: The MICOIL Pilot Study2020
An RCT in mild cognitive impairment found 50 mL/day high- or moderate-phenolic olive oil for 12 months improved cognitive scores versus Mediterranean diet advice alone.
- Effect
- Benefit
- Duration
- 12 months
- Dose
- 50 mL/day
- Population
- Adults
ResveratrolView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- A small study in people with mild memory problems found that taking resveratrol with quercetin daily for 26 weeks did not improve learning or memory compared to placebo.
- The study was small, so this might be why it did not detect a real benefit.
Browse 1 study
RCTImpact of Resveratrol on Glucose Control, Hippocampal Structure and Connectivity, and Memory Performance in Patients with Mild Cognitive Impairment2017n=22
In 40 mild cognitive impairment patients, resveratrol 200 mg/day for 26 weeks improved hippocampal connectivity and glucose control versus olive oil placebo.
- Effect
- Benefit
- Dose
- 200 mg/day
- Population
- Older adults
- Participants
- 22
- Ages
- 50–80
TheanineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is unclear if taking L-theanine by mouth helps with thinking and memory problems.
- One small study found that a product with L-theanine and green tea extract taken twice daily for 16 weeks helped improve memory and attention in people with mild cognitive problems.
- But when people with general memory complaints were included, no improvement was seen.
Browse 1 study
RCTA combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study2011n=12
In a 16-week RCT of 91 adults with mild cognitive impairment, a green tea extract and L-theanine combination improved memory and attention scores versus placebo.
- Effect
- Benefit
- Duration
- 16 weeks
- Dose
- 1680 mg/day
- Population
- MCI patients
- Participants
- 12
- Avg age
- 57±9
Vitamin KView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It isn’t clear whether eating more foods rich in vitamin K can slow the development of memory or thinking problems.
- However, in one study of adults aged 55 to 75 with weight and metabolism issues, people who increased their vitamin K intake the most over two years had less decline in thinking and memory scores compared with those who increased it the least.
Browse 1 study
Vitamin K dietary intake is associated with cognitive function in an older adult Mediterranean population2022n=5,533
In a study of 5,533 participants, 194.4 μg/day, after adjusting for potential cofounders, the highest tertile of change of dietary vitamin K intake (median [IQR]; 194.4 μg/d [120.9, 373.1]) was inversely associated with a Mini-Mental State Examination (MMSE) score ≤24 (OR [95% CI]; 0.53 [0.35, 0.79] P for trend = 0.002) compared with...
- Effect
- Benefit
- Dose
- 194.4 μg/day
- Population
- Women
- Participants
- 5,533
- Avg age
- ~65
L-TryptophanView supplement →
Do not purchase·★★★★★
How we scored this▸
- In older adults with mild memory problems, taking a supplement containing L-tryptophan plus omega-3 fatty acids, vitamin E, soy phospholipids, and melatonin every night for 12 weeks led to small improvements in thinking and sense of smell compared to a placebo.
- People who took the supplement improved slightly on a memory test, while those who took placebo got worse.
- It is not clear which ingredient is responsible for the benefit.
Browse 1 study
RCTEffects of a diet integration with an oily emulsion of DHA-phospholipids containing melatonin and tryptophan in elderly patients suffering from mild cognitive impairment2012n=11
In 25 elderly adults with MCI, 12 weeks of DHA-phospholipid emulsion with melatonin and tryptophan did not significantly improve cognition versus placebo.
- Effect
- No Benefit
- Duration
- 12 weeks
- Population
- Older adults
- Participants
- 11
- Avg age
- ~86±6
Nicotinamide RibosideView supplement →
Do not purchase·★★★★★
How we scored this▸
- It's not clear if nicotinamide riboside helps memory or thinking in older adults with mild memory problems.
- In one small study, people took increasing doses up to 1 gram a day for 10 weeks and saw no difference compared to a placebo.
- Another small study using 1 gram a day for 8 weeks also found no benefit.
Browse 2 studies
RCTCognitive and Alzheimer's disease biomarker effects of oral nicotinamide riboside (NR) supplementation in older adults with subjective cognitive decline and mild cognitive impairment2025n=46
In 46 older adults with subjective cognitive decline or MCI, 8 weeks of nicotinamide riboside 1 g/day did not improve RBANS cognition vs placebo in a crossover trial.
- Effect
- No Benefit
- Duration
- 8 weeks
- Dose
- 1 g/day
- Population
- Older adults
- Participants
- 46
- Ages
- 55+
RCTA randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment2023n=20
In 20 older adults with MCI, 10 weeks of nicotinamide riboside 1 g/day safely doubled blood NAD+ but did not change MoCA or other cognitive scores vs placebo.
- Effect
- No Benefit
- Duration
- 10 weeks
- Dose
- 1 g/day
- Population
- Older adults
- Participants
- 20
Vitamin DView supplement →
Do not purchase·★★★★★
How we scored this▸
- It is not clear if vitamin D helps older adults with mild thinking and memory problems.
- A small study found that taking vitamin D three times a week, along with exercise and brain training, did not improve thinking skills compared to exercise and brain training alone.
- Most people in the study already had enough vitamin D at the beginning of the study.
Browse 1 study
RCTEffects of Exercise Alone or Combined With Cognitive Training and Vitamin D Supplementation to Improve Cognition in Adults With Mild Cognitive Impairment: A Randomized Clinical Trial2023n=18
In the SYNERGIC trial of 175 older adults with mild cognitive impairment, aerobic-resistance exercise with cognitive training improved cognition; vitamin D 10,000 IU three times weekly had no added benefit.
- Effect
- No Benefit
- Duration
- 20 weeks
- Dose
- 1000 IU/day
- Population
- Women
- Participants
- 18
- Ages
- 60–85
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Melatonin | ★★★★★52% | 5 | 1 | 29% |
| Nicotinamide Riboside | ★★★★★32% | 2 | 0 | 12% |
| Olive Oil | ★★★★★44% | 2 | 0 | 12% |
| Ashwagandha | ★★★★★44% | 1 | 0 | 6% |
| L-Tryptophan | ★★★★★32% | 1 | 0 | 6% |
| Lion's Mane Mushroom | ★★★★★44% | 1 | 0 | 6% |
| Nattokinase | ★★★★★44% | 1 | 0 | 6% |
| Resveratrol | ★★★★★44% | 1 | 0 | 6% |
| Theanine | ★★★★★44% | 1 | 0 | 6% |
| Vitamin D | ★★★★★32% | 1 | 0 | 6% |
| Vitamin K | ★★★★★40% | 1 | 0 | 6% |