Almost anything can be a toxin when not taken in moderation, just like high levels of fluoride consumption can have ill effects, even though regulated water fluoridation can have well-recognized benefits in helping prevent tooth decay.
Nicotine has really surprising health benefits, which are only now being appreciated. I understand it's hard for many to dissociate nicotine from the bad associations to tobacco health concerns, and of course despite any benefits, you certainly don't want to sit there and drink a toxic dose of the stuff.
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Okay, I'm not suggesting that the OP not try to quit smoking, but if nicotine is the main issue, then there are certainly healthier ways to consume it (vaping can help because it still carries that inhalation of particles that smokers are so used to).