A composition suitable for use in nicotine replacement therapy products includes a nicotine product that includes a synthetic nicotine that is substantially free of one or more contaminants and/or impurities normally associated with tobacco-derived nicotine. For example, the synthetic nicotine is substantially free of one or more of nicotine-1'-N-oxide, nicotyrine, nornicotyrine, 2',3-bipyridyl, cotinine, anabasine, and/or anatabine. The composition further comprises one or more pharmaceutically acceptable excipients, additives and/or carriers. The nicotine replacement therapy products may include any number of such products, including transdermal nicotine delivery patches, nicotine gums, synthetic chewing tobacco, synthetic snuff, and synthetic strips (e.g., dissolvable synthetic tobacco). Additionally, a method of treating nicotine addiction includes administering a nicotine replacement composition, e.g., via a nicotine replacement therapy product, to a user.