Nicotine is the addictive substance present in tobacco crops. Benzoic acid can be naturally present in plants, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and clinical studies suggest 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 interior respiratory tract—to express completely different immune proteins. Some of those protein adjustments have been linked to bronchial asthma. Sign up for our Health Tip of the Day publication, and obtain day by day tips that will assist you to live your healthiest life.