Nicotine is the addictive substance found in tobacco vegetation. Benzoic acid is also naturally present 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 clinical research from 2018 that found that the compounds modified vapers’ sputum—the mucosal lining that covers the interior respiratory tract—to specific completely different immune proteins. Some of these protein changes have been linked to asthma. Sign up for our Health Tip of the Day e-newsletter, and obtain day by day tips that will assist you to stay your healthiest life.