Nicotine is the addictive substance in tobacco that makes smoking so pleasurable as well as so hard to quit. Many quit smoking products such as inhalers, gums, lozenges and e-cigarettes contain nicotine. Nicotine by itself is not dangerous; it is the multitude of other chemicals in tobacco smoke that cause the diseases which make smoking such a deadly habit.

In 1996, a group of researchers led by H L Waldum published the results of their experiment into the effects of inhaling nicotine vapour over an extended period of time on rats (Waldum H L, Nilsen O G, Nilsen T, Rorvik H, Syversen V, Sanvik A K, Haugen O A, Torp S H & Brenna E (1996) Long-term effects of inhaled nicotine, Life Sciences, Volume 58, Issue 16, 1339-1346). The laboratory rats were put in a chamber into which nicotine vapour was pumped for 20 hours per day, five days a week for two years. The experiment concluded that there was no increase in the death rate, and there was no increase in the likelihood of developing tumours. The researchers concluded that “our study does not indicate any harmful effect of nicotine when given in its pure form by inhalation.” Interestingly, the rats lost weight as well.

The appetite suppressing effects of nicotine have been studied in an effort to produce new medicines that can help people lose weight. In fact, people have known for centuries that nicotine is an appetite suppressant. The famous Italian explorer Christopher Columbus was initially angry upon learning that the sailors on his ships had picked up the habit of smoking tobacco from the inhabitants of the New World. He changed his mind, however, when he discovered that smoking suppressed their hunger. The sixteenth century Spanish physician Nicolas Monardes wrote in his History of Medicinal Plants in the New World in 1571 that tobacco had the ability to alleviate hunger and thirst. Monardes had a rather naive view of tobacco, writing that “To seek to tell the virtues and greatness of this holy herb, the ailments which can be cured of it, the evils from which it has saved thousands would be to go on to infinity … this precious herb is so general a need not only for the sick but for the healthy”. Throughout the twentieth century, tobacco companies marketed cigarettes as a product that could help men and women maintain a slim body. Kensitas cigarettes were marketed in the 1920s as an appetite suppressant and people were advised to substitute them for snacks in between meals. A famous marketing campaign by Slim cigarettes during the 1980s warned women that if they put on weight, they would lose their male partners to skinnier women who smoked Slim cigarettes.