Flavorless e-juice, also known as unflavored e-juice or nicotine base, typically contains only two primary ingredients: propylene glycol (PG) and/or vegetable glycerin (VG) and nicotine. These liquids are used as a base for mixing with other e-juice flavors or can be used on their own. Since they don't contain any added flavorings, they typically have a very neutral taste with a slightly sweet aftertaste.