Most "brain" supplement claims go well beyond the evidence. The FDA sent warning letters to companies illegally selling dozens of products, many sold as supplements, that claimed to treat Alzheimer's disease. The FTC took Prevagen's makers to court over memory claims. It said the company's own study failed to show the product worked better than placebo, and in 2024 the court ordered the claims stopped. Look for ingredients tested in people, and expect small effects.
- L-theanine with caffeine: in a lab study of 27 volunteers, 100 mg of L-theanine with 50 mg of caffeine improved attention-switching and reduced distraction within 90 minutes. The effects are short-term. See our L-theanine and caffeine pages.
- Bacopa: a meta-analysis of 9 trials lasting 12 weeks or more found faster attention, and called the evidence not yet definitive. One trial in people over 65 found 300 mg a day improved delayed word recall. More on our bacopa page.
- Citicoline: in 75 healthy teenage boys, 250 or 500 mg a day for 28 days improved attention and motor speed. It has not been shown in adults.
- Lion's mane: in 30 older Japanese adults with mild memory problems, about 3 g a day of powder for 16 weeks improved scores, which fell again after stopping. The manufacturer ran the trial.
- Ginkgo for memory: in the GEM trial, more than 3,000 people aged 75 and over took 120 mg twice a day for about 6 years. Ginkgo did not reduce dementia or slow cognitive decline. See our ginkgo page.
- Claims to prevent, treat or reverse Alzheimer's or dementia.
- "Clinically proven" or "increases IQ" claims.
- Proprietary "nootropic matrices" with many ingredients at unknown doses.
- High-caffeine stacks. Count every source of caffeine.
Match the ingredient to the result you want: short-term focus (L-theanine with caffeine) or gradual changes over 12 weeks (bacopa). Give a product the full trial period before judging it. Memory problems that are new or getting worse need a doctor, not a supplement.
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