Transcranial Direct Current Stimulation (tDCS) FAQ

Common Pitfalls and Commonly Asked Questions about tDCS:

Transcranial direct current stimulation (tDCS) involves applying a low level electrical current to specified brain regions to modulate the neural circuits/highways in the brain (What is tDCS?). By electrically stimulating or inhibiting different regions of the brain, the hypothesis is that one can stimulate or inhibit specific neural circuits, and hypothetically strengthen or weaken those circuits over time (see my article on Neuropriming). There is a growing body of evidence that supports the effectiveness of tDCS in various psychiatric and neurological disorders. There are also studies that suggest that tDCS can enhance cognitive functions in healthy individuals.

Below, you will find a compiled a list of common pitfalls that DIY tDCS users make when using their devices, which can lead to a lack of effect or undesired results due to improper use. The latter portion of the article contains a compiled a list of answers to commonly asked questions about tDCS.

Disclaimer: Brain augmentation techniques such as those described in our website are not reviewed or approved by the FDA. The long-term consequences of tDCS may not be well understood. However, we accept that use of these techniques occur, and we believe that offering responsible, harm-reduction, and scientifically-recognized information is imperative to keeping people informed. For that reason, the articles, guides, courses, and videos in our website are designed to expand knowledge of those who decide to pursue/research these techniques.


Common Pitfalls:

Pitfall #1: Not using enough saline to soak electrodes.

This will impede conductivity of electricity and prevent a circuit formation. This is especially important if the user has a thick head of hair (it is also important to part hair at electrode site as effectively as possible).

It is also important to not oversaturate electrodes with saline (i.e., saline will run down scalp if electrodes are oversaturated). Oversaturated electrodes can decrease effectiveness of stimulation.


Pitfall #2: Using Electrode gel instead of saline solution.

Electrode gel is not ideal for the majority of tDCS devices offered online, aside from the fact that it can lead to a frustrating, gooey mess. Electrode gel also dries out more quickly and is more often associated with skin burns.

Most tDCS electrodes are meant to be soaked in saline solution.

Saline solution can easily be made at home (easy solution recipe: 1 tablespoon non-iodinized, non-preservative salt + 1 cup warm water), and many tDCS sites provide recipes for creating saline. 

Pitfall #3: Not washing electrode sponges and mesh after use.

This can lead to premature rusting of the device.


Pitfall #4: Overusing the tDCS beyond the time used in research studies.

Research studies typically use 20-30 minute sessions. Exceeding duration time can potentially be harmful and/or reverse the desired effect.



Commonly Asked Questions about tDCS:


Question #1:

Where do I place the red electrode (anode) and where do I place the black electrode (cathode)?

Answer: In most tDCS devices, the red electrode is typically the ‘anode,’ which is the positively charged electrode. The anode electrode usually leads to increased activity of the underlying brain region.

The black electrode is referred to as the ‘cathode.’ The cathode is the negatively charged electrode and usually leads to decreased brain activity of the stimulated region. Depending on the desired effect, electrodes are placed on different regions of the brain.

Sometimes, one of the electrodes (usually the cathode) is placed on a different part of the body as a ‘reference’ electrode.

The specific organized placement of electrodes is called the montage. Each montage is designed to produce a different desired effect (example: tDCS protocol for depression utilizes the F3 anode/Fp2 cathode montage). Montages are based on a specific head measuring system called, the “10-20 System.”


Question #2: 

Where do I place the electrodes?

Answer: Different tDCS protocols call for different montages (different electrode placement). There are variety of tDCS protocols that are posted on the Internet, designed for different desired effects. For instance, one might use a depression montage if one wants to improve mood. If a person desires to enhance their cognitive functioning, he/she may use the DARPA montage designed to improve memory or learning. Each montage is meant to stimulate a unique neural circuit/highway so that a desired effect is produced (i.e., improved mood, improved memory, improved creativity, etc).

However, not all protocols are created equally. It is important to understand that certain protocols have more evidence to support efficacy, while others have little evidence to support efficacy.

This is why it is important to understand and stay up-to-date on tDCS research (tDCS research gets confusing and complicated, which is why experts recommend against DIY tDCS use). There is much information on the internet that is simply not true and may potentially be harmful long-term.


Question #3: 

Do I need to use both electrodes at the same time during my tDCS session?

Answer: Yes. It is important to use both the anode (positively charged electrode) and cathode (negatively charged electrode) during the session in order to create a closed electrical circuit. This allows electrical current to flow. If only one electrode is used, electrical current will not flow and stimulation will not occur.


Question #4: 

Are TENS units similar, and can someone use that in place of tDCS? 

Answer: No. TENS units are not suited for tDCS because they generate higher current levels and oscillate at frequencies different from tDCS devices. Therefore, TENS units are not suitable as a tDCS device.


Question #5: 

Is it really necessary to see amount of current on a tDCS device?

Answer: There are a variety of devices on the market, some of which have an amperage (current) meter. Without an amperage meter, there is no way of knowing whether the device is actually delivering the appropriate amount of current to the brain. Having a tDCS device with an amperage meter may be helpful to identify whether there is too little or too much current being delivered to the brain. 


Question #6:

How often should someone use their tDCS?

Answer: Most tDCS studies use 20-30 minute sessions for 10-15 days. Experts will caution not to use tDCS for longer than 20-30 minutes because the effects on the brain may actually reverse if tDCS is used for longer. For example, if a person uses a depression protocol for longer than 30 minutes, resulting effects may be worsening mood (this has something to do with the complicated nature of neurons and will not be covered in this article). There are few research studies that study effects of tDCS beyond the initial 10-15 day use phase. Continuation of tDCS treatment was evaluated in one study. It was a six month prospective observational study of 26 patients who responded to initial acute treatment for depression. The maintenance therapy consisted of once weekly tDCS treatments initially followed by one session every two weeks. The majority of patients who underwent maintenance tDCS therapy maintained an anti-depressant effect.

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Disclaimer: The information and devices displayed on this site are not intended to treat, cure, or prevent any medical disease, and this article is not considered to be medical advice. If a reader decides to purchase and use a tDCS machine, it is his or her responsibility to use it correctly and safely and ensure that it works correctly.