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People are zapping their brains at home to improve focus and clear brain fog. But is it safe?

At-home brain stimulation is flourishing among a group of enthusiasts, who say it gives them a mental edge. The science behind why it may work is still in the early stages.
Illustration of a person pouring a cup of coffee as a sparking plug plugs into the back of their head.
At-home use of brain stimulation devices is picking up speed faster than scientists' ability to determine how well it works. Liza Evseeva / NBC News

In 2021, Craig Gibbons was diagnosed with Lyme disease. His doctor prescribed him antibiotics, but the medication failed to eliminate one of his most debilitating symptoms: a lasting brain fog that made it difficult for him to focus or recall information.

So he went with a different approach: at-home brain stimulation.

Over the past few years, Gibbons had been experimenting with transcranial direct current stimulation, or tDCS, which delivers weak electrical currents to the brain through electrodes attached to the head.

Brain stimulation comes in many different forms, but they are all centered on the same idea: sending tiny zaps to specific parts of the brain to alter its activity. Some of its uses are well-established: transcranial magnetic stimulation is used in hospitals and clinics as a way to treat depression. Another version, deep brain stimulation, involves surgically implanting electrodes in the brain, and has been used for years to ease symptoms of Parkinson's disease.

Gibbons, 32, of New York City, had heard it could be used to alleviate symptoms of brain fog.

“It helped wake me up a little bit and get things going,” he said.

Most brain stimulating techniques involve placing electrodes — conductors through which electricity travels — on certain parts of a person’s head. These electrodes send tiny electrical impulses through the skull to the brain. 

Medical uses of brain stimulation typically take place in hospitals or doctors' offices. But the use of at-home brain stimulation devices is flourishing among a group of enthusiasts, who say it enhances their mental state and gives them an edge, like on an upcoming exam or a project at work. Others credit it as a way to achieve deeper meditative states or mental clarity.

The at-home devices are available online and typically range in cost from as little as $40 to around $500. They are usually no bigger than a television remote or a smartphone; batteries, head caps and straps, saline and other accessories needed to send the weak pulses of electricity to the brain are sometimes sold separately. 

Many of them are marketed as having clearance from the Food and Drug Administration, which entails a less rigorous review process than what’s needed for FDA approval.

Despite their growing popularity, many scientists oppose the use of the devices at home because not much is known about their safety in the long term, said Robert Reinhart, a neuroscientist at Boston University.

“We are talking about injecting electricity into someone’s brain. Someone could get hurt,” he said. “We need to better understand what these tools can do including any unintended consequences they may have.”

Science in its early stages

Anna Wexler, an assistant professor of medical ethics and health policy at the University of Pennsylvania, studies why and how people use brain stimulation at home. She's found that people are using the devices to treat mental health disorders or to improve mental performance.

“Depression and anxiety are the top two indications for people,” Wexler said. “But other reasons people used it for were for enhancement, so to improve focus, to improve memory, things like that.”

At-home brain stimulation began in earnest in the early 2010s, Wexler said, despite pushback from clinicians and scientists, who were concerned about safety.

“They weren’t too pleased that individuals were essentially using the same technology as they were doing but doing it at home, so using similar devices to stimulate their own brains with low levels of electricity at home,” she said.

The science behind why electrically stimulating the brain appears to aid memory and thinking abilities is still in the early stages, Wexner noted.

Reinhart led a study, published in August in the journal Nature Neuroscience, that found that delivering small electric zaps to the brain appeared to boost memory in a group of older adults for at least one month. The study included 150 people ages 65 to 88 who did not have a diagnosed neurological disorder. Patients were asked to wear a cap embedded with electrodes for 20 minutes on four consecutive days. The type of stimulation was similar to transcranial direct current stimulation, but used a different type of electrical current.

The findings suggested that aside from its clinical use, brain stimulation could one day become mainstream, similar to the way people use caffeine to increase alertness, he said.

“You can imagine a future potentially where people are using stimulation,” Reinhart said. “I think people are just overwhelmingly interested in augmenting their ability to provide a kind of cutting-edge advantage.”

Online buzz

Transcranial direct current stimulation has gained traction online. The subreddit r/tDCS is dedicated to discussing the science, technology and use of brain stimulation devices. The group boasts more than 16,000 members.

Phil Doughan, 66, of McLean, Virginia is among them. 

He said he became interested in brain stimulation after listening to a podcast on Radiolab, as well as an audiobook, both on the topic.

In January, he purchased a tDCS device from medical equipment supplier Caputron for about $450, with the hope that it would enhance his meditation practice, as well as help clear brain fog, which he attributed to his age.

“I am not looking to fix anything I perceive as broken; I am looking for improvement in my mind,” Doughan said. 

Kathie Kane-Willis, 53, of Michigan, said she's been using a tDCS device that she purchased online for $250 to help alleviate some of her long Covid symptoms, including brain fog.

Since purchasing the device last spring, she said, many of her symptoms have eased. 

“I’m not as brain foggy,” said Kane-Willis, who uses the device for 20 minutes at least twice a day. “It really calms you down; it’s almost like meditating.”

But whether the at-home devices actually help improve people's mental performance is up for debate, Reinhart said, noting that the public adoption of tDCS is happening faster than the accumulation of scientists’ knowledge about the method.

Wexler said she doesn’t expect brain stimulation to achieve mainstream success until studies conclusively show that it provides real benefits.

“The baseline question is whether this is actually working,” she said. “It could be a placebo, it could not be working at all.”

To Dr. Michael Fox, an associate professor of neurology at Harvard Medical School, it’s no surprise that at-home brain stimulation has gained a fan base.

“The promise of being able to noninvasively put on a cap for 20 minutes a day and change or enhance your cognitive function is something that gets people excited,” he said.

Still, he said users should proceed with caution. In a 2016 editorial in the journal Annals of Neurology, Fox warned that at-home brain stimulation comes with some risks, some more readily apparent than others.

Known side effects can include itching, tingling sensations or small burns. Proponents of at-home use argue that these side effects are minimal, and people should be able to use them at their own risk, he said.

But brain stimulation may have more wide-ranging effects: it may enhance some cognitive abilities at the cost of others, Fox said. And while the electrical zaps are targeted, stimulation affects more parts of the brain than the user may think.

Fox said he would prefer that people interested in brain stimulation use it under medical supervision.

But for those in favor, he said, the argument goes, “we modify our brain function routinely with things like caffeine and alcohol. I can buy a cup of coffee off the shelf and I can buy a beer off the shelf. And one argument is, why can’t I buy a brain stimulation device off the shelf?”

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