Memodyne Official Website › The memory supplement guide
The memory supplement guideThe Memory Supplement Guide: the shelf, the claims and the evidence
Memory supplements are a large and fast-growing market built on ingredients that were mostly studied for something else. This guide sets out what is on the shelf, what the published record supports, what the claims are permitted to mean, and what the randomised trials of non-supplement interventions actually found.
Written by the Memodyne Team at Memoadyne, a retail desk that sells one product in this category and says so on every page.
What is on the shelf
One review, 103 products, and the pattern they share.
A 2023 review in CNS Drugs did the useful thing: its authors walked into local and national pharmacies and grocery stores, wrote down every memory supplement on sale, and worked through the evidence for each. They collected 103 products.
The picture that emerges is consistent. The category is built on a handful of recurring ingredients, combined into branded blends, sold on structure and function claims, and supported mostly by research on single ingredients in populations that are not the buyer. The review also notes the market size behind it: a brain health supplement industry valued in the billions and forecast to roughly double.
- Vitamins and minerals, where the evidence is about correcting a deficiency.
- Botanical extracts, where the evidence is mixed and the best-studied examples are decades old.
- Amino acids from sports nutrition, where the evidence is about blood flow and exercise capacity.
- Fish oils and phospholipids, where the evidence is largely observational.
- Novel branded compounds, where the evidence is usually a single small trial funded by the manufacturer.
The amino acid group, in detail
The group with the cleanest mechanism and the least cognitive evidence.
Because it is the group this desk knows best, and because it is where the most confident-sounding marketing tends to be, the nitric-oxide amino acids are worth taking slowly.
Nitric oxide is built from arginine, and it is what persuades the muscle in an artery wall to let go. Swallowed arginine is mostly destroyed in the gut, so citrulline, which is absorbed intact and converted to arginine in the kidney, does the job better. The crossover study that established this gave 20 healthy volunteers six regimes over a week each and found citrulline raised plasma arginine dose-dependently, with the top arm at 3 g twice a day.
For outcomes rather than markers: a meta-analysis of 22 arginine trials found a 6.40 mmHg fall in systolic pressure with the effective amount at 4 g a day or more, and a 2025 meta-analysis of 15 citrulline trials found 4.02 mmHg in middle-aged and older adults. The arginine AKG trial used 12 g a day for eight weeks.
What none of that literature contains is a memory endpoint. The nearest is a crossover trial in twelve taekwondo athletes measuring reaction time after simulated matches, on a mixture of about 12 g of branched-chain amino acids with about 3.5 g each of arginine and citrulline for a 70 kg adult. Anybody selling this group for memory is extrapolating from blood vessels, and the honest ones say so.
What the randomised evidence actually supports
Three randomised programmes, and the thread that links them to a bottle.
A guide that only described supplements would be leaving out the part a reader most needs. Three bodies of randomised evidence exist for cognitive outcomes in older adults, and none of them is a product.
| Intervention | The trial | What it found |
|---|---|---|
A structured lifestyle programme | US POINTER, 2,111 adults aged 60 to 79, two years | Both arms improved; the structured arm improved faster, by 0.029 SD a year |
A multidomain programme in at-risk adults | FINGER, 1,260 Finnish adults, two years | A measured difference on a comprehensive neuropsychological battery |
Exercise | A 2026 network meta-analysis, 38 trials, 2,928 adults over 65 | Aerobic exercise improved all three executive-function domains in cognitively healthy adults |
These are not alternatives this desk sells. They are the comparison any honest guide to this category has to print.
The thread connecting those to a supplement shelf is vascular risk. Blood pressure is a modifiable risk factor for cognitive decline, the lifestyle programmes above all included vascular risk monitoring, and the amino acids discussed earlier have a small measured effect on blood pressure. That is a real connection and it is a thin one. It is not a licence to describe a capsule as a memory treatment.
How to use this guide in a shop
Five steps, in the order a shopper can actually do them.
Turn the bottle round
If there is no Supplement Facts panel, you cannot evaluate the product and neither can anybody else. That is not a reason never to buy it; it is a reason to know what you are doing.
Count the ingredients you can put a number against
A blend total is not a number. Neither is a name on a marketing graphic.
Compare one ingredient with one trial
Pick the one the marketing leads with. If the trial used ten times what a serving could carry, the rest of the label is decoration.
Read the claim as a permission, not a finding
Supports is a permitted word. Treats is not. Clinically proven should be followed by the name of a trial, and usually is not.
Check the way out before the way in
The refund window, who pays return postage, and whether a human answers the telephone. On this site those are on the refund policy page.
Sources for this guide
Every trial and reference named above.
- Hersant H, He S, Maliha P, Grossberg G. Over the Counter Supplements for Memory: A Review of Available Evidence. CNS Drugs. 2023;37(9):797-817. PMID 37603263. https://pubmed.ncbi.nlm.nih.gov/37603263/
- Schwedhelm E, Maas R, Freese R, et al. Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism. Br J Clin Pharmacol. 2008;65(1):51-9. PMID 17662090. https://pubmed.ncbi.nlm.nih.gov/17662090/
- Shiraseb F, Asbaghi O, Bagheri R, Wong A, Figueroa A, Mirzaei K. Effect of l-Arginine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-Response Meta-analysis of Randomized Clinical Trials. Adv Nutr. 2022;13(4):1226-1242. PMID 34967840. https://pubmed.ncbi.nlm.nih.gov/34967840/
- Luo P, Chen J, Liu K, Zhang J. Does l-citrulline supplementation and watermelon intake reduce blood pressure in middle-aged and older adults? A systematic review and meta-analysis of randomized controlled trials. Clin Nutr ESPEN. 2025;69:653-664. PMID 40789388. https://pubmed.ncbi.nlm.nih.gov/40789388/
- Campbell B, Roberts M, Kerksick C, et al. Pharmacokinetics, safety, and effects on exercise performance of L-arginine alpha-ketoglutarate in trained adult men. Nutrition. 2006;22(9):872-81. PMID 16928472. https://pubmed.ncbi.nlm.nih.gov/16928472/
- Chen IF, Wu HJ, Chen CY, Chou KM, Chang CK. Branched-chain amino acids, arginine, citrulline alleviate central fatigue after 3 simulated matches in taekwondo athletes: a randomized controlled trial. J Int Soc Sports Nutr. 2016;13:28. PMID 27418883. https://pubmed.ncbi.nlm.nih.gov/27418883/
- Baker LD, Espeland MA, Whitmer RA, et al. Structured vs Self-Guided Multidomain Lifestyle Interventions for Global Cognitive Function: The US POINTER Randomized Clinical Trial. JAMA. 2025;334(8):681-691. PMID 40720610. https://pubmed.ncbi.nlm.nih.gov/40720610/
- Ngandu T, Lehtisalo J, Solomon A, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet. 2015;385(9984):2255-63. PMID 25771249. https://pubmed.ncbi.nlm.nih.gov/25771249/
- Quan J, Zhu L, Chen Z, Chen Z, Li B, Yu S. Optimal type and dose of exercise for improving executive functions in older adults: a systematic review and Bayesian model-based network meta-analysis of RCTs. BMC Geriatr. 2026;26(1). PMID 42260365. https://pubmed.ncbi.nlm.nih.gov/42260365/
- Health Products Compliance Guidance. U.S. Federal Trade Commission, December 2022. https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance
- Memory, Forgetfulness, and Aging: What's Normal and What's Not? National Institute on Aging, National Institutes of Health. https://www.nia.nih.gov/health/memory-loss-and-forgetfulness/memory-forgetfulness-and-aging-whats-normal-and-whats-not
- Alternative Treatments. Alzheimer's Association. https://www.alz.org/alzheimers-dementia/treatments/alternative-treatments
