Nicotine is also found in other plants of the Solanaceae such as tomatoes and aubergine, albeit at much lower levels than in the tobacco plant.
Normal bodily functions involve nicotinic acetylcholine (nACh) receptors, which are present in various tissues throughout the body, including the brain, nerves and muscles. Acetylcholine binds and activates nACh receptors, promoting the release of neurotransmitters that convey chemical messages to neighbouring cells. While nicotine's effects on the body are complicated and continue to be studied, nicotine can also bind to these receptors, triggering the release of neurotransmitters that have both a stimulating and depressing influence on the body. The resulting effects range from increased blood pressure and heart rate, dizziness and nausea to increased concentration and feelings of pleasure and relaxation.1,2,3,4
Ingestion of high doses of nicotine (purposefully or accidentally) can be fatal, though typically overdosing on nicotine products is unlikely both because of the individual ability to titrate dose and the short half-life of nicotine. People unaccustomed to nicotine exposure are likely to experience dizziness and nausea at concentrations much lower than are tolerated by regular users of nicotine. While low doses of nicotine, such as those generated by nicotine patches used for nicotine replacement therapy are unlikely to cause dependence, levels of nicotine found in vapour and tobacco heating products are likely to cause dependence. Dependence is thought to be associated with both the dose of nicotine and the speed of nicotine delivery. While use of nicotine alone is considered to be much less hazardous than cigarette smoking, nicotine is not risk-free.5,6
It is well established that smoking cigarettes is a substantial cause of smoking-related diseases such as COPD and cancer, but it is the other toxic chemicals present in the smoke – not the nicotine – that are the main constituents that cause such diseases. The scientific consensus is that nicotine has not been established to cause by itself cardiovascular disease or cancer 5.
Studies have identified the following health risks associated with nicotine:
Because of this, e-liquids carry the warning that nicotine products are not suitable for use by: persons under the age of 18; persons who are allergic/sensitive to nicotine; pregnant or breast-feeding women; persons who should avoid using tobacco or nicotine products for medical reasons; or persons with an unstable heart condition, severe hypertension or diabetes.
Neurobiology of Nicotine Addiction: Implications for Smoking Cessation Treatment.
Nicotinic Acetylcholine Receptors and Nicotinic Cholinergic Mechanisms of the Central Nervous System.
A systematic review of possible serious adverse health effects of nicotine replacement therapy.
Nicotine without smoke: Tobacco harm reduction.
Stopping smoking by using other sources of nicotine.
The Health Consequences of Smoking—50 Years of Progress.
Bruin, J. E., H. C. Gerstein, and A. C. Holloway. 2010. Toxicological Sciences 116(2):364-374.
Long-term consequences of fetal and neonatal nicotine exposure: A critical review.
Cardiovascular Toxicity of Nicotine: Implications for Electronic Cigarette Use.