flavoring sold in South Asia Dissolvable tobacco, a variation on chewing tobacco that completely dissolves in the mouth Toombak and shammah, preparations found in North Africa, East Africa, and the Arabian peninsula Topical tobacco paste, a paste applied to the skin and absorbed through the dermis Since there are varied manufacturing methods, products can differ greatly in chemical arrangement and nicotine level. Smokeless tobacco products typically contain over 3000 constituents which play a part in their taste as well as scent. Nicotine levels Smokeless tobacco differs depending on the type of product, the types of tobacco used, and the amount of each tobacco type used within a product. Each variable results in different level of nicotine. Furthermore, nicotine is absorbed by the body to different degrees depending on the pH level of the product, which is known as the free nicotine or unionized nicotine level. Below are some measured nicotine levels of various smokeless tobacco products from 2006 and 2007 and their corresponding free nicotine levels as calculated by the Henderson–Hasselbalch equation. Prevalence More than 300 million people are using smokeless tobacco worldwide. People of many regions, including India, Pakistan, other Asian countries, and North America, have a long history of smokeless tobacco use. Once addicted to nicotine from smokeless tobacco use, many people, particularly young people, expand their tobacco use by smoking cigarettes. Because young people who use smokeless tobacco can become addicted to nicotine, they may be more likely to also become cigarette smokers. Youth are particularly susceptible to starting smokeless tobacco use. Males were more likely than females to have used smokeless tobacco in the past month. In 2014, 3.3 percent of people aged 12 or older (an estimated 8.7 million people) used smokeless tobacco in the past month. Past month smokeless tobacco use remained relatively stable between 2002 and 2014. Past month smokeless tobacco use between 2002 and 2014 was mostly consistent among adults aged 26 or older. There was more variability in the percentages of young adults aged 18 to 25 and adolescents aged 12 to 17 who used smokeless tobacco between 2002 and 2014. Smokeless tobacco use for adolescents aged 12 to 17 was higher during the mid-2000s, but the 2014 estimates were closer to the lower levels seen in the early 2000s. In 2014, an estimated 1.0 million people aged 12 or older used smokeless tobacco for the first time in the past