That's a bunch of bullshit. Nicotine gum does not increase the risk of lip and jaw cancer. This has been studied to death. https://archive.is/4nAit It also does not damage tooth enamel (as long as you aren't grinding your teeth). Nicotine is basic, not acidic. It also doesn't work if your mouth is acidic. It has to be slightly alkaline for you to absorb the drug. If anything it increases saliva production which calcifies your teeth.