Nicotine is relatively harmless, all the harm from smoking comes from tobacco smoke

Public Health England

Public Health England, Guidance: Health matters: stopping smoking – what works?, December 2019

• The widespread misconception among smokers and health professionals that most of the harm of smoking comes from the nicotine is one of the greatest obstacles faced by Public Health England.
• Nicotine replacement therapy (NRT) is a safe form of treatment and licensed for use even in pregnancy and for people with cardiovascular disease. 
• Nicotine increases heart rate and blood pressure, and has a range of local irritant effects, but is not a carcinogen.
• It is the tar and carbon monoxide in cigarette smoke, along with more than 400 other toxins, that causes almost all of the harm of smoking.
• The three main causes of mortality from smoking are lung cancer, Chronic obstructive pulmonary disease (COPD) and cardiovascular disease, none of these are caused by nicotine.
• Using NRT or e-cigarettes (vaping) makes it one and a half times as likely a person will succeed in quitting.

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