I've always thought that nicotine has really bad health effects.
Interestingly enough, I've found the following statement on the website of one of the major Nicotine Replacement Therapy products producers:
Myths: Nicotine is carcinogenic
Fact: Nicotine is not proven to cause cancer. There are more than 4,000 other chemicals in cigarette smoke, many of which are known to cause cancer. In particular it is the polycyclic aromatic hydrocarbons and nitrosamines that are the probable causative agents for lung and other cancers. The risks associated with NRT, to aid with nicotine withdrawal, significantly outweighed by the risks of smoking.
Myths: Nicotine causes the diseases related to smoking
Fact: Cigarettes are a well-known cause of cancer, chronic lung disease, heart disease, and other disorders. It is the myriad of toxins in cigarette smoke, rather than the nicotine content, that is responsible for the majority of the harmful effects. In other words, it is the delivery system, not the addictive drug, which is responsible for the vast majority of tobacco-related diseases.
Myths: Nicotine is responsible for adverse health effects related to smoking
Fact: The main adverse nicotine effect in tobacco products is nicotine addiction, which sustains tobacco use. Because most smokers are nicotine-dependent, they continue to expose themselves to toxins from cigarettes. It is the other chemicals in cigarettes, not nicotine, which are responsible for most of the adverse health effects
In other words, the only thing one should be worried about with nicotine is the addiction that—potentially—comes with it (and they actually say that it's only addictive when smoked because of the "hit").
Why not use nicotine to achieve its beneficial effects?
At low doses, nicotine potently enhances the actions of norepinephrine and dopamine in the brain, causing a drug effect typical of those of psychostimulants. At higher doses, nicotine enhances the effect of serotonin and opiate activity, producing a calming, pain-killing effect.
The question: while there is little doubt that NRT products help a bit to quit smoking, the statements on Nicorette's web site seem to me quite unbelievable. What is actually proven about the safety or toxicity of nicotine?