Nicotine has been studied extensively because of its presence in tobacco products. Because of its chirality, nicotine can exist in two enantiomeric forms; however, the tobacco plant produces predominantly (S)-nicotine with only a trace of (R)-nicotine. Consequently, consumers of tobacco products have been exposed to rather small amounts of (R)-nicotine over the years. Recently, synthetic nicotine has become commercially available and can be supplied as pure (S)-nicotine or as a ≥ 50/50 (S)/(R) mixture. Synthetic (S)-nicotine can be obtained by asymmetric synthesis or by racemic synthesis followed by classical resolution using diastereomeric salts. The primary objective of this study was to determine the amount of (R)-nicotine in commercial sources of tobacco-derived US Pharmacopeia (USP) nicotine, synthetic nicotine, and in e-liquids used in Electronic Nicotine Delivery Systems (ENDS). A secondary objective was to examine the literature on the pharmacology of (R)-nicotine considering the potential exposure to tobacco consumers. Nicotine samples were analysed by either chiral GC-MS and or chiral HPLC-UV. The analysis of four lots of tobacco-derived, USP nicotine revealed only a small amount of (R)-nicotine, whereas one sample of synthetic nicotine was found to contain a 50/50 mixture of enantiomers. Analysis of two lots of e-liquids used in ENDS indicated that each contained a 50/50 mixture of (R)- and (S)-nicotine and was synthetic. In this study, large amounts (50%) of (R)-nicotine were found in some commercial nicotine sources. Consequently, tobacco consumers may be subjected to higher (R)-nicotine exposure levels than in the past. A literature review indicated that with some exceptions (R)- and (S)-nicotine were found to exhibit a similar pharmacological profile, with (R)-nicotine being often but not always less pharmacologically active than (S)-nicotine.