Nicotine is the addictive substance present in tobacco vegetation. Benzoic acid is also naturally found in vegetation, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and scientific studies counsel that glycerin and propylene glycol irritate the lining of the lungs. One small medical research from 2018 that discovered that the compounds changed vapers’ sputum—the mucosal lining that covers the inner respiratory tract—to precise different immune proteins. Some of these protein adjustments have been linked to asthma. Sign up for our Health Tip of the Day publication, and receive day by day suggestions that can assist you to stay your healthiest life.