How Much of Our Brain Do We Use?

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The human brain is complex and mysterious. This may be why questions and misconceptions about how the brain works persist. Many people are curious about what percentage of our brain we use. The answer is all of it! How much of your brain you are using at any given time varies depending on what you are doing or thinking, but is not true that humans only use a small part of the brain's power.

The popular belief that we only use 10% of our brain leads people to speculate that we could tap into a deep well of potential if only we could use our brain's full capacity. But the only time certain regions of the brain are unused is when brain damage or disease has destroyed those areas.

Evidence That We Use Our Whole Brain

Despite the misconception that people are either right-brained or left-brained, decades of studying the human brain and its abilities have shown scientists that every part of the brain has a purpose and is critical to human function. While there is still much to learn, there is also a lot of support for these claims.

Brain Imaging

Functional magnetic resonance imaging (fMRI) allows scientists to investigate how the brain works in a noninvasive way. They can view how blood and oxygen are moving in the brain while a human test participant is performing various mental tasks (or even just resting). These tests make it clear that large regions of the brain are at work during all kinds of activity.

Researchers have not found any region of the brain that does not serve a function. A study of medical myths noted that "numerous types of brain imaging studies show that no area of the brain is completely silent or inactive."

Brain Damage

The effects of brain damage, whether caused by injury, stroke, or diseases such as dementia, show how important all parts of the brain are. There isn't a single area of the brain that can be damaged without resulting in some sort of consequence.

Brain Size

Neuroscientists note that the human brain is proportionally larger than the brains of other animals, even our close primate relatives. We would not have evolved such large brains if we were only using a tiny portion of them.

Brain Energy Use

The brain uses approximately 20% of the body's energy, even though it makes up much less than 20% of total body mass. As with brain size, evolutionary theory suggests that it would make little sense for the body to spend a large portion of its energy resources on an organ that's mostly unused.

How to Improve Brain Function

While our bodies already do a good job of using all parts of the brain, there are steps we can take to keep our brains healthy and strong. Maintaining good overall health can help slow brain aging and even protect against Alzheimer's disease.

Eat Nutritious Foods

Research suggests that certain micronutrients can play a role in brain health. Eating a diet rich in antioxidants, such as vitamin E and beta carotene, can help protect against many chronic diseases and also promote a healthy brain. You'll find antioxidants in brightly colored fruits and vegetables, such as blueberries, spinach, and sweet potatoes.

Omega-3 fatty acids, which are most commonly found in fish, are also essential to brain health. Try to consume at least two servings a week, or talk to a doctor about whether fish oil supplements are right for you.

Exercise Your Brain

You've seen the apps that promise to stop your brain from aging. There is some truth to their claims; cognitive training does help reduce the risk of dementia.

But any form of mental exercise can be effective. Try crossword puzzles and other word games, jigsaw puzzles, reading, or learning a new skill. Adding social stimulation (such as learning a new language in a group setting) supports brain health even more.

Exercise Your Body

Physical exercise is important for physical health, but also for mental health—and for brain health. Physical activity actually changes the structure and function of the brain, which helps keep it working well. Exercise increases blood flow to the brain and helps deliver energy, in the form of glucose, to the brain's cells. And exercise has both short- and long-term effects.

Get Enough Sleep

Just as nutrition and exercise support both physical and brain health, so does good quality sleep. Sleep can improve memory recall and "reduce mental fatigue," according to research. "Each phase of the sleep cycle restores and rejuvenates the brain for optimal function," note the authors of a study on the protective effects of sleep on the brain.


Drinking enough water not only protects you from symptoms like headache and dizziness. Your brain also needs plenty of water to function at its best.

At least one study showed that even being slightly dehydrated (by as little as 2%) can result in impaired cognitive function. So be sure to sip on plenty of water and other non-alcoholic, decaffeinated beverages to fuel your body and brain.

A Word From Verywell

It's a misconception that humans only use a small portion of our brains, and that we have could unlock some kind of hidden brain potential by taking a medication or supplement. We are already using most of this complex organ. But we do have the power to keep the brain healthy and strong by stimulating it regularly and giving it the nutrition, hydration, and rest that it needs.

14 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Kendra Cherry
Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology.