Taping some wires to your skull and connecting them to a 9-volt battery sounds kinda wild, right?

But could a couple of milliamps of current from a 9-volt battery actually boost your brain power? Lower your anxiety? Eliminate depression? Turn you into a hyper focused productivity machine?

Sounds kinda crazy, like some crackpot science, right?

Maybe not…

Benefits of tDCS

While it’s still a very experimental strategy, increasing numbers of people are trying transcranial direct-current stimulation, more commonly known as tDCS, to enhance learning, focus, decision-making, creativity and more. I first learned about it through the RadioLab podcast, “9 volt nirvana” which I highly recommend listening to. Amazing stuff.

Meanwhile, doctors are studying the technique as a potential treatment for all kinds of ailments and plenty of people are reporting anecdotal evidence to suggest it has some pretty incredible results.

tDCS for depression

In one study, which described tDCS as a novel non-pharmacological treatment for depression, they found results were mixed. Some participants reported improved mood and relief from depressive symptoms. Others not so much. Still, it appears to be roughly as effective as prescription medication.((

Reduced anxiety

One study reported participants had a significant decrease in anxiety, specifically associated with obsessive-compulsive disorder.

Treating addiction

One study showed an improvement in the ability to quit tobacco, although they claim the results were mixed, and perhaps the participants who showed favorable results were more inclined to actually want to quit.((

Stroke recovery

In one interesting study, researchers found tDCS helped improve the quality of life and significantly lowered depression in stroke patients. They attribute this to “the increase in brain activity in patients with stroke” given that tDCS can help enhance the excitability of the cerebral cortex.((

Relief from mental disorders such as schizophrenia


Help treat alzheimer’s disease

Some studies have shown promising results using tDCS to help alzheimer’s patients, in particular to help them retrieve words and improve communication. In one study they gave six 30-minute sessions over ten days.

Another study in Nature claimed that 40mz light helped clear beta amyloid plaques in mice

Improved cognitive ability

Maybe instead of cramming for that final test with a caffeine fueled all nighter you should strap on some electrodes. There’s quite a bit of evidence suggesting transcraniel stimulation can help improve cognition in a bunch of ways.

In one study by DARPA (the military Defense Advanced Research Project Agency) they found that tDCS had a significant effect of improving cognition in macaques who were tested to perform certain tasks based on learning associations between visual cues and a location1

So yea, there’s quite a bit of legit research on top of anecdotal evidence suggesting that zapping your brain might have some pretty incredible results.

Is this much different than electroshock therapy?

The idea of using electricity to treat mental illness is nothing new, of course, and despite lingering negative associations with the somewhat barbaric overuse of electroshock therapy in the mid-twentieth century, it’s an idea that makes a lot of sense. Neurons are electrically activated, after all, so it’s inevitable that subjecting them to an electrical field would have some effect, and research has confirmed that the effect is often medically beneficial.

Shock treatment, now rebranded as ECT, continues to be used for major depression and bipolar disorder. Deep brain stimulation (DBS), in which electrodes are actually implanted inside the skull, has received FDA approval for treatment of Parkinson’s disease(( and obsessive–compulsive disorder.((

Obviously, those are both fairly risky procedures, and ECT and DBS are both very different from tDCS. You wouldn’t dream of trying them at home, and even doctors are reluctant to use them except as a last resort against serious illness. That’s pretty much ruled out research into their potential for cognitive enhancement in healthy people (although DBS has shown some promise for improving cognitive function in patients with dementia).((

Less intense, noninvasive transcranial magnetic stimulation (TMS) has been found to enhance cognitive performance in healthy human subjects,(( but the sophisticated and expensive medical equipment it requires makes it impracticable for home use.

Why tDCS is different

It still supplies neuron-stimulating current straight to the cerebral cortex, but that current’s on the order of 2mA – a mere quarter of a percent of the 800mA used in ECT. Safety has been conclusively established for up to an hour a day of 4mA tDCS,(( a generous margin over the most common regimen of 2mA for 20 minutes every two days. And not only is it entirely possible to safely use a tDCS device at home, you can buy one for just $150 – or build one yourself for even less.

That’s made tDCS a darling of a growing DIY brain hacking community over the last decade, and it’s only gained momentum following the October 2017 publication of a DARPA-funded study(( crediting the technique with an astonishing 40 percent increase in learning speed.

Aside from more efficient learning (especially of math, music and languages), laypeople are reporting success in using tDCS to overcome eating disorders, improve social skills, alleviate depression, and even get a better night’s sleep – and scientific research is often supporting these firsthand testimonials.((

Recommended tDCS Devices

Interested in giving tDCS a try for yourself? With a number of quality devices now on the market, it’s never been easier. It’s hard to pick one single “best tDCS device” but we found a few reputable ones, reviewed below.


TheBrainDriver is a good entry level, consumer grade tDCS device priced at around $150. It fits in your pocket, weighs less than a pound, and runs off a 9-volt battery, so it’s extremely portable. An LCD display and digital controls make it very simple to use, too: all you do is select one of four current levels (0.5mA, 1.0mA, 1.5mA & 2.0mA) and set the timer to either 20 or 30 minutes. That’s about all you can do, but that’s more than enough for most purposes.


If you want more flexibility – and more power – you can get an American-made ApeX Type A 18V system for about the same price. Running on two 9-volt batteries, the ApeX is said to produce more reliable stimulation, and it has a built-in current meter to prove it. (While the meter goes up to 5mA, the output is safety-limited to 2mA.) The analog control dial eliminates the interference associated with digital control, resulting in cleaner current, and the progressive adjustment is more comfortable as well.

Downsides? The ApeX isn’t all that portable – if you want to take it on a trip, you’re invited to shell out another hundred bucks for a hard-shell travel pack – and it doesn’t have a timer.

Caputron ActivaDose

A decidedly more advanced – and, at about $400, more expensive – option is the Caputron ActivaDose II. This medical grade device is the one used in many scientific studies of tDCS. It has a high-contrast LCD display, but you control the current, up to a 4mA maximum, with a rotary knob.

There’s another knob that lets you select the total dose (i.e., milliamps × minutes), and the ActivaDose will automatically recalculate the time remaining if you change either dose or current settings during a session. To keep things comfortable, current transitions are also automatic. An alert will sound when the time’s up, or in the event of a low battery or open circuit.

Make your own tDCS

Of course, direct current circuits aren’t all that complicated. If you’re any kind of electronics hobbyist, making your own tDCS device is practically a no-brainer. Youtube is filled with videos explaining how to make your own tDCS device.

Even if you’ve never so much as put together a transistor radio kit, you might want to give it a try – it’s actually even easier, and it’ll save you an awful lot of money.

You’ll only need about an hour of time and 10 to 20 dollars worth of tools and materials:

• Soldering iron
• Hot glue gun
• Multimeter
• Scissors
• Wire stripper
• Perfboard
• Battery
• Switch
• Transistor
• Resistors
• Electrical tape
• Sponges
• Alligator clips
• Wire

Wiring diagrams and detailed instructions are available at places like Instructables, YouTube, and MakeUseOf.

Recommended Placement (aka Montages)

The various benefits of tDCS come from stimulating different areas of the brain. To get the effect you want, you need to position the electrodes so that the current passes through the corresponding part of your cerebral cortex. Fortunately, you don’t have to figure that out yourself.

Medical researchers have developed a number of so called “montages” showing recommended placements for everything from insight to impulse control. They’re described by letters and numbers such as FP1 and T4, which refer to specific places on the skull. For example, the DARPA montage for accelerated learning has the anode at F10 (the right temple) and the cathode on the left arm or shoulder.(( Another well-documented placement is anode F3 / cathode FP2 for depression and anxiety.((

You can find many more montages at various tDCS sites, but you’ll also find that the experts don’t always agree on the best positioning for particular purposes. The very active tDCS forum on Reddit is a good place to find anecdotal accounts of what’s worked for individual users.

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