Saline solution refers to the mixture of NaCl sodium chloride, aka salt, and water. Saline solution is commonly used in medicine to cleanse wounds, treat dehydration, and cleanse and preserve contact lenses. Non-invasive brain stimulation techniques like transcranial direct current stimulation (tDCS) utilize sponge electrodes to apply current to targeted brain regions. Sponges are used because when wetted they allow current to flow through any hair located on the head. Since water by itself isn't a great conductor of electricity, it is best to use a saline solution to ensure that current reaches the cranium with the least amount of resistance.
Saline solution can easily be made at home using tap water and standard table salt. The optimal concentration of salt for use with transcranial stimulation is 0.9%.  This equates to approximately 2.3 grams of salt per a standard 8oz glass of water. For convenience, we sell a Saline Solution Applicator Bottle which includes accurate mixing instructions printed right on the bottle. This 2oz pointed-spout squeeze bottle makes it incredibly easy to apply saline solution directly, and evenly across the sponge electrodes. Furthermore, the liquid seal cap means you can travel with your saline solution, even while flying as it complies with all TSA travel guidelines!
The Saline Solution Applicator Bottle comes included with every Deluxe tDCS Kit, or can be purchased individually through our online store.