If you would take the time to read the studies you'd find nicotine is beneficial to your health. It's a natural substance in a lot of vegetables. It has anti-bacterial properties, it's a nootropic (smart drug) and enhances cognitive ability, it's anti-inflammatory and it's a stimulant just like caffeine and is no more addictive than caffeine. Acutely, potential side-effects of nicotine are similar to acute side-effects of other stimulants such as yohimbine or caffeine due to increasing catecholamines. The problems come when smoking it, smoking anything causes problems. And also the additives added to nicotine products are harmful in many ways.