Nicotine is one of the most misunderstood chemicals on the planet. It is the most well-known chemical in tobacco smoke and many people incorrectly believe it is the main cause of the death and illness from smoking as well. Even doctors are confused.
Nicotine is habit-forming but is otherwise relatively benign and has some positive effects. Let’s find out more and bust some myths!
This is a summarised extract from my book, Start Smoking Stop Vaping, which examines the scientific evidence for vaping and nicotine and provides step-by-step advice on how to make the switch from smoking tobacco.
Is nicotine harmful to the body?
Nicotine is a toxic poison in its highly concentrated form but the low concentrations in smoke and vapour cause little harm with normal use. According to Public Health England, ‘Nicotine use per se represents minimal risk of serious harm to physical health’. The UK Royal College of Physicians concluded ‘‘Use of nicotine alone, in the doses used by smokers, represents little if any hazard to the user.’
Nicotine increases the heart rate and blood pressure and narrows the blood vessels, much like mild exercise. It may exacerbate existing heart conditions and can trigger an irregular heartbeat in some cases. However, the effects are minor compared to tobacco smoking.
Nicotine reduces the blood flow to wounds and can delay healing, for example after surgery and can raise blood sugar levels.
Does nicotine harm the adolescent brain?
There is no evidence so far that nicotine harms the human brain in adolescence. Concerns of harm to brain development from nicotine are based on rat and mouse studies.
However, laboratory tests often use unrealistic doses in an artificial setting and are far more sensitive to nicotine than humans. As one review concluded, animal tests generally ‘fall far short of being able to predict human responses.’
However, further research is needed to identify any possible long-term effects.
Is nicotine harmful in pregnancy?
Nicotine has been linked to harmful effects on the foetus in mouse and rat studies. However, there is no clear evidence that these findings apply to humans.
Nicotine replacement products such as patches, gums and lozenges are approved for use in pregnancy in Australia and have not shown any clear harms.
Nicotine may not be completely safe for the pregnant mother and foetus, but it is always safer than smoking.
How strong is dependence on nicotine?
Dependence on nicotine varies with how it is administered, how quickly it reaches the brain and how much is used.
Dependence is most potent from smoking because high doses of nicotine get to the brain very quickly, within ten to fifteen seconds — faster than intravenously injected heroin.
Vaping and nicotine replacement therapy deliver nicotine more slowly and usually to lower levels. Many studies have found that vaping nicotine causes less dependence than smoking.
Is long-term use of nicotine harmful?
We know that the long-term use of nicotine is low-risk from decades of use of ‘Swedish snus’. Snus is a moist, pasteurised, finely-ground form of tobacco usually sold in a pouch like a small teabag. It is placed under the upper lip where it slowly releases similar levels of nicotine to tobacco smoking.
A review by Public Health England concluded that ’long-term use of nicotine as snus … has not been found to increase the risk of serious health problems in adults.’
There is also no evidence of harm from long-term use of nicotine in nicotine replacement therapy.
Does nicotine have positive effects?
Many smokers enjoy the effects of nicotine. Nicotine releases the pleasure hormone ‘dopamine’ in the brain creating pleasure and a sense of reward.
Nicotine reduces your appetite and can help to reduce weight gain.
Dr Colin Mendelsohn is a medical practitioner who works exclusively in tobacco treatment, helping smokers quit. He is a member of the committee that develops the RACGP Australian national smoking cessation guidelines and is the Founding Chairman of the Australian Tobacco Harm Reduction Association.
He is actively involved in research, writing and teaching about smoking cessation and tobacco control.