For musicians, athletes or artists, practice makes perfect – because repetition creates neural pathways in the brain. That’s what trascranial direct current stimulation, or tDCS, hopes to do – provide a shortcut to virtuosity, by passing low-level electrical currents to particular regions of the brain and ‘exciting’ the areas that have to do with motor control and cognition.

Scientists have been studying the potential medical and cognitive benefits of transcranial direct current stimulation for years. A new study found that tDCS could have a beneficial effect in improving sports performance, by boosting “motor or perceptual learning,” and another study measuring hand motor functions found that tDCS could improve that as well, particularly in older people. And when it comes to treating depression, a 2013 study found that the employment of tDCS had mixed, but positive, results in treatment of major depressive disorder (MDD).

While research remains preliminary, however, there are now plenty of people who are exploring tDCS on their own terms, using homemade devices to stimulate their brain into focusing more while playing video games, for example. But clinicians are warning consumers about the possible downfalls of such homemade devices. “If tDCS is powerful enough to do good, you have to wonder if, done incorrectly, it could cause harm,” Dr. H. Branch Coslett, chief of cognitive neurology section at the University of Pennsylvania School of Medicine, told the New York Times.

Don’t Try It At Home

Some, anxious to try a tDCS device at home, have been turning to a $249 readymade called Foc.us. Foc.us is a headset developed for ‘gamers’ and hasn’t been approved by the FDA yet, but has been entirely sold out, according to its website. The headset can be monitored using an iPhone or iPad app through a touch sensor. Foc.us became popular amongst gamers and members of a Reddit subgroup devoted to tDCS, eager to experiment with stimulating electrical currents on themselves. Others have created build-your-own tDCS devices and have posted Youtube videos describing their experiences.

“Overclock your brain using transcranial Direct Current Stimulation (tDCS) to increase the plasticity of your brain,” Foc.us writes on its website. “Make your synapses fire faster… Faster Processor, Faster Graphics, Faster Brain!”

Michael Oxley, the founder of Foc.us, said on the website that his motivation behind creating the headset stemmed from his being “frustrated that however much I read about tDCS there was no easy way to try it.” But medical experts warn consumers to be cautious about the homemade devices, as they are not approved by the FDA and are unregulated by medical professionals. “What makes me very nervous about the Foc.us and homemade tDCS devices is the intensity and duration of current people are getting,” Dr. Michael Weisend, a cognitive neuroscientist at Wright State Research Institute in Ohio, told the New York Times. “We have zero data on long-term use on anybody’s brain, and I have scars to prove that you can burn yourself pretty badly with tDCS.”

If the electrodes are not placed properly on the head in order to stimulate the correct brain regions, it might lead to injury or to disrupting other parts of the brain. “What we’ve found is brain power is like a blanket,” Dr. Roi Cohen Kadosh, a neuropsychologist, told the New York Times. “You pull it over to one side and something else is not covered.”

Steven Novella writes on Science Based Medicine that [E]xactly where the electrodes are placed on the scalp, how strong the stimulation is, how long it is applied, and the details of the pattern of electrical activity all potentially affect the net effect on brain function,” and that “[o]verall this does not seem like the kind of treatment that should be given over-the-counter.”