Nicotine is bonded to a resin called polacrilex in a pharmaceutical formulation known as nicotine polacrilex, or nicotine gum. When nicotine is released gradually from the gum when it is eaten, this compound helps lessen the cravings and withdrawal symptoms that come with stopping smoking. Nicotine polacrilex is absorbed by the oral mucosa.

However, another chemical type of nicotine that is commonly found in e-liquids for vaping is called nicotine salt. Unlike traditional "freebase" nicotine found in regular e-liquids, nicotine salt e-liquids contain nicotine in its natural condition in a modified form that makes it smoother to inhale and more quickly absorbed by the body.