Nicotine is the addictive substance found in tobacco plants. Benzoic acid can also be naturally found in plants, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and scientific studies recommend that glycerin and propylene glycol irritate the lining of the lungs. One small clinical research from 2018 that found that the compounds changed vapers’ sputum—the mucosal lining that covers the interior respiratory tract—to express totally different immune proteins. Some of these protein changes have been linked to bronchial asthma. Sign up for our Health Tip of the Day publication, and obtain every day ideas that will assist you to stay your healthiest life.