Transcranial Direct Current Stimulation Claims, Safety, and Overview

When we wake up in the morning, we often drink a cup of coffee to help us wake up and get ready for the day. But what if we could do the same thing by wearing a device that sends electric currents to our brains? This is the truth about transcranial direct current stimulation, even though it may sound like science fiction (tDCS).

tDCS devices are popular among people who want a quick brain boost, but the FDA has not yet approved them. Because they are not regulated, it is hard to know if they are safe and if they work. So, we need to be careful when thinking about these devices.

tDCS is said to have many benefits, such as making it easier to pay attention and remember things. But the evidence for these claims is often mixed and not very strong. Some studies have found positive results, while others have found either nothing or even bad results.

Even though there isn't much known about tDCS devices, they are becoming easier to get. You can now buy tDCS devices for your home. It's important to remember that using tDCS to self-treat or manage a brain condition without the help of a doctor is dangerous.

What is transcranial direct current stimulation (tDCS)?

Transcranial direct current stimulation, or tDCS, is a way to stimulate parts of the brain by using low levels of electrical current. In the past few years, it has become more popular as a possible way to improve brain function and treat brain diseases like depression, ADHD, and Alzheimer's.

In tDCS, electrodes are put against the scalp by a device that is worn on the head. When the switch is turned on, the electrodes send a small amount of electricity to the brain. Sessions of treatment usually last 20 to 30 minutes and may be repeated over several days or weeks.

tDCS is a fairly new technology, but other ways to stimulate the brain have been around for a long time. For example, transcranial magnetic stimulation (TMS) uses a device worn over the forehead and magnetic fields to stimulate certain brain parts. Electroconvulsive therapy (ECT) uses a higher level of electrical current to cause a short seizure in the brain, while deep brain stimulation (DBS) uses electrodes that are surgically implanted to send electrical pulses to certain parts of the brain.

The FDA has approved TMS to treat depression and obsessive-compulsive disorder, while ECT works very well for people with severe depression who haven't gotten better with other treatments. DBS is used to help people with Parkinson's disease, epilepsy, and tremors who don't get better with medicine. However, tDCS devices have not yet been approved by the FDA to improve brain function or treat brain disorders, so they should be used with care.

tDCS Claims

Transcranial direct current stimulation (tDCS) supporters say that stimulating certain parts of the brain with low levels of electricity can have a number of benefits. These include better focus, memory, and clarity of thought, as well as more energy and motivation.

Also, some supporters say that tDCS can help people with COVID-19, Lyme disease, or other conditions get rid of "brain fog." People also think that tDCS can help reduce the signs of depression, anxiety, and drug or smoking cravings, as well as help people with ADHD or Alzheimer's disease.

Even though some studies support these claims, the evidence is still limited and mixed. Since tDCS devices have not yet been approved by the FDA, people should be careful when thinking about using them to improve brain function or treat brain disorders.


Transcranial direct current stimulation (tDCS) is still being studied to find out how well it works. Some studies show that tDCS may be helpful for some conditions, but it's important to keep in mind that the methods used in research studies may be different from those used in devices that can be bought and used at home. For example, electrodes may be placed more precisely over a certain part of the brain, and sessions may last longer or happen less often.

Current research shows that tDCS may help people with depression, Alzheimer's disease, and ADHD in the short term. For example, an analysis of 10 randomized trials showed that some people who got tDCS treatment had less depression symptoms or even got rid of their depression, compared to those who got a fake treatment. A review of seven studies also found that people with mild to moderate Alzheimer's disease had better memory and other cognitive skills after 20 to 40 minutes of tDCS. Lastly, one randomized study of 64 adults with ADHD found that 30 minutes of tDCS daily for a month improved their attention.

It's important to remember that these studies were small and focused on short-term effects. More research is needed to find out if tDCS is safe and effective over the long term and if it can be used to treat certain conditions.

Take Away and Recommendations

Transcranial direct current stimulation (tDCS) has been deemed safe for adults by the FDA, but there are some things to think about before using it. For example, the treatment may cause itching, irritation, or small burns where the electrodes are placed. Some people also say they feel tired or have headaches.

Since there haven't been any large, long-term studies of tDCS, it's hard to say how safe it is in general, and some experts worry about the risks of using it at home. For example, it's not clear how much of the brain besides the targeted areas is affected, what might happen if tDCS is used in different ways, or how long any changes in the brain, whether they were meant to happen or not, could last.

Also, not much research has been done on tDCS in children, so we don't know what effects it might have on a child's developing brain.

Lastly, tDCS devices can be expensive. Some cost several hundred dollars or more, and health insurance usually doesn't cover them.

So, it's still unclear how tDCS should be used and who it might help the most. If you want to try tDCS, it's important to know that we still don't know much about its safety and effectiveness. If you don't like taking risks, it might be best to wait until more research is done on its benefits and risks. In the meantime, you can clear your mind with your morning coffee.

By Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. As a practicing rheumatologist for over 30 years, Dr. Shmerling engaged in a mix of patient care, teaching, and research. His research interests center on diagnostic studies in patients with musculoskeletal symptoms and rheumatic and autoimmune diseases. He has published research regarding infectious arthritis, medical ethics, and diagnostic test performance in rheumatic disease. Having retired from patient care in 2019, Dr. Shmerling now works as a senior faculty editor for Harvard Health Publishing.

Twitter: @RobShmerling

William H. McDaniel, MD

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School.

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