Do brain supplements work? Thirteen popular ones checked against the human evidence

How to read the evidence table

Each row is one supplement. The second column is what the label or the ads promise. The third is the best human evidence the book could find. The last column is the badge.

The book uses four badges for its drills: SOLID, PROMISING, STORY ONLY and MYTH. For the supplement table it adds two more. WEAK means the human studies for the marketed claim are few, small, mixed, tied to the company, or found no benefit in healthy adults. NO HUMAN EVIDENCE means the claim rests on animal or cell studies only.

The three rows we left out of the table, glycine, chamomile and zinc, all rate WEAK too. Not one of the thirteen earns a SOLID.

We are not giving doses, and we are not telling you to start or stop anything. Some of these have real side effects or clash with medicines. The book names fish oil with blood thinners, and chamomile with warfarin. If you take medication or have a health condition, talk to your doctor or pharmacist first, and bring the bottle.

Standing in the brain health aisle

The shelf is bright. One bottle has a glowing brain on it. Another lists a dozen words you have never seen. A month's supply costs about as much as a nice dinner.

Online it gets louder. Special magnesium. Mushroom powder. A "stack" that claims to build new brain wiring.

It all sounds very scientific. And you have no way to check it standing there.

Here is the part the labels skip. In the US, supplements are not approved by the FDA before they go on sale. And what is in the bottle may not match the label. In a study published in 2021, a team led by Pieter Cohen tested ten "cognitive enhancement" products and found five drugs that are not approved in the US. Some were above doses a doctor would prescribe.

That study picked products whose labels already listed unapproved drugs, so it does not describe every brain pill. It does show how loose the market can be.

What a seal on the bottle does and does not tell you

If you buy supplements, the book points to third-party seals such as USP or NSF. According to the National Institutes of Health, those seals check that a product was made properly, holds what the label says, and is not contaminated.

They do not tell you if it works. They do not tell you if it is safe for you.

What about ginkgo?

Ginkgo is one of the oldest memory pills on the shelf, and it is not in the book's table. So we went to the US government's National Center for Complementary and Integrative Health.

Its answer is plain. Ginkgo has not been shown to prevent dementia or slow it down. The biggest test, the GEM study, followed more than 3,000 people aged 75 or older for a median of six years. Some took ginkgo and some took a dummy pill. There was no difference in how many got dementia.

NCCIH also warns that ginkgo may raise the risk of bleeding in people who take blood thinners such as warfarin. Ask your doctor or pharmacist before you try it.

So which supplement is best for memory?

This is the question most people type in. Based on the book's table, there is no clear winner for a healthy adult.

The closest thing to a yes is creatine, rated PROMISING, with a modest memory signal mostly in older adults. Caffeine with L-theanine can help attention for an hour or two, and the caffeine does most of the work.

One case is different. If you are low in vitamin B12, that is a real medical problem. It needs a doctor's diagnosis, not a guess from the supplement aisle. In people who are not low, the book found no memory benefit from B12 or folate.

The book also notes that magnesium can clash with certain antibiotics. That is one more reason to show your pharmacist any bottle before you start it.

Where the better brain evidence is

This is the problem The Genius Lab was written for: a shelf full of brain claims, checked one by one.

Sleep, Movement, and the Supplement Aisle has the full table of thirteen, with the reasoning behind every badge. It also covers the two things that beat every bottle. Sleep after learning helps you keep facts, and there is a simple drill to test it on yourself. Walking helps you come up with ideas: in the first experiment of a 2014 Stanford study, 81 percent of the 48 people came up with more ideas while walking than sitting. The chapter also checks the famous claim that exercise grows part of your brain by 2 percent, and why that number is shaky.

Switching Fast, and What Switching Costs does the same job for brain training apps. Our page on brain training games has the short version.

How to Use the Lab explains the four badges and what each one can hold, so you can weigh the next brain claim you see.