Few things are more important than having a healthy brain—but what does “brain health” mean, exactly? It feels like every day I encounter a new multivitamin, health app, or wearable with some version of the promise that the product will “support cognitive function,” “sharpen focus,” and of course, “improve brain health.” 

As long as these products don't make claims about treating specific diseases, the FDA doesn’t require a strict definition of what that actually means. As a result, “brain health” can mean different things to a supplement company, a meditation app, or an actual neurologist. Meanwhile, consumers are left grasping at straws trying to evaluate these claims. 

Before you can judge whether a product delivers what it promises, you need to understand what “brain health” actually means, what parts of it can even be measured, and what the evidence behind popular products and protocols actually shows.

What brain health really means

There's no set definition of "brain health." It varies depending on who’s using it. Brain health is, “one of the most commonly used terms in wellness and healthcare, but it is also one of the least precisely defined," says neuroscientist Dr. Ramon Velazquez. The phrase may refer to “cognitive performance, emotional well-being, stress resilience, sleep quality, neurological function, or long-term protection against age-related cognitive decline."

In other words, brain health can mean many different things. What’s important to know as a consumer is that it cannot be boiled down to a single number or biomarker. At the same time, most of the domains within brain health—cognition, focus, and so on—are measurable in some way. Here's a look at what the science shows, so you can be armed against all the snake oil language running rampant in wellness spaces.

How is brain health measured?

Velazquez shares the main categories researchers and clinicians actually use to measure brain health:

• Cognitive performance tests. Standardized assessments of memory, attention, processing speed, and executive function form the backbone of cognitive neuroscience research. These tests are not perfect instruments, but they are specific, reproducible, and have established norms across age groups.

• Sleep quality. Polysomnography, the clinical gold standard, measures brain activity, eye movement, muscle tone, and respiratory function during sleep to characterize sleep stages and detect disorders. Consumer wearables approximate some of this with heart rate data, though their accuracy is up for debate.

• Mood and stress resilience. There are validated scales, like the PHQ-9 for depression, GAD-7 for anxiety, and the Perceived Stress Scale to quantify psychological states that are closely linked to brain function. There are also metrics like heart rate variability that can paint a fuller picture using self-reported data.

• Neuro-imaging. These tools are expensive and primarily used in research settings, but they provide objective, anatomy-level evidence of brain changes.

The point is, "no single metric captures brain health in its entirety," Velazquez says. "Brain health is best viewed as a multidimensional concept, and any product claiming to improve it should be able to demonstrate measurable benefits in one or more of those domains." The brain is extremely complex—far more complex, at least, than certain products want you to think.

Can any products actually improve brain health?

Any product making a brain health claim should be able to point to evidence of improvement in at least one of the domains above: cognitive test performance, sleep quality, mood or stress resilience, and neuro-imaging markers. (There's also research about blood-based biomarkers, but that's still pretty far from consumer products at this time.)

Outside of these categories, claims about improving overall brain health are "difficult to validate, because the term encompasses many different biological and psychological processes," Velazquez says. Here’s what the science actually shows about different “brain health” products you might encounter day-to-day. (I am not a doctor—my goal here is to debunk marketing language. If anything here has been recommended to you personally by a medical professional, always stick to those recommendations.)

Supplements

The “brain health” supplement market is enormous, and its marketing language runs almost entirely on vague, unverifiable claims. I’m not saying that the main vitamins and nutrients in these supplements don’t help your brain at all; studies show that omega-3 fatty acids can help increase learning, memory, cognitive well-being, and blood flow in the brain (though that’s mostly for older adults; effects in healthy younger adults are more modest). In the same vein, there are tentative findings that lion's mane mushroom (Hericium erinaceus) can help improve cognitive function and mood. 

What I am saying is that there just isn’t enough evidence from randomized clinical trials that isolating these ingredients in pill form will truly give you a brain boost. And I’m not the only one saying it—Harvard Medical School is too. That’s why products claiming to "boost brain health" with “proprietary blends” warrant skepticism. There’s a good chance the doses are below those that the underlying studies used, and that the marketing claims are too broad to be falsifiable. A more honest version of supplement marketing might say something like: "Contains DHA, which has been associated with improved memory performance in older adults in randomized controlled trials." But that’s not going to get units flying off shelves.

Health apps

Some research shows that “brain game” apps—like Luminosity and BrainHQ, for example—do show promise in improving cognitive function and mood. However, this promise is based on findings that these apps can lead to improvements on the tasks you practice within that app. That’s a pretty big leap from in-app games to real-world cognitive performance. In fact, the Federal Trade Commission has previously taken action against Lumosity for deceptive advertising—specifically for implying that the apps would protect against dementia and age-related cognitive decline without adequate evidence. That's an illustration of exactly why the definition of “brain health” is so murky in advertising: The marketing claimed total brain health while the evidence, at best, supported specific in-task performance. For the most part, all the broad claims about improving overall brain health or preventing cognitive decline are not supported for most of these “brain game” products.

Wearables

Where smartwatches gave us visibility into our physical states, brain wearables promise to illuminate the black box of our mental performance. I've previously written about this new frontier of wearables that claim to "read your mind," and I can sum it up like this: The technology is too immature, the regulatory landscape too barren, and consumer wariness is too high for these to gain mainstream adoption any time soon.

Discussion of your smartwatch is relevant here—specifically, your sleep score, as sleep plays a key role in your cognitive function. While sleep scores are cool number to consider, it’s important to remember that this number is an approximation, and each company has its own grading system for it. Still, tracking your sleep is useful, as long as it prompts real behavioral change to get better sleep over time. When in doubt, read up on the fundamentals of sleep hygiene.

The bottom line

Before trusting a brain health claim, tap into your inner scientist and start asking questions. What specific outcome is being measured: memory, attention, sleep, stress, a biomarker? What population was studied, and does it match one you're a part of? Was there a control group? Was the study independent of the company selling the product? Has it been replicated?

The claim "this improves brain health" fails this test immediately, because it’s just not specific enough. On the flip side, something like "improved short-term memory recall on validated tests in adults over 60 in a randomized controlled trial" is a claim that can be evaluated.

The irony is that the interventions with the strongest evidence across the most domains of brain health—regular aerobic exercise, consistent quality sleep, stimulating activity, stress management, and a healthy diet—are not the ones supported by the largest marketing spend.