Nicotine is the addictive substance found in tobacco plants. Benzoic acid can be naturally present in plants, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and medical research counsel that glycerin and propylene glycol irritate the liner of the lungs. One small clinical examine from 2018 that discovered that the compounds modified vapers’ sputum—the mucosal lining that covers the inner respiratory tract—to express completely different immune proteins. Some of those protein changes have been linked to bronchial asthma. Sign up for our Health Tip of the Day newsletter, and obtain daily tips that may assist you to stay your healthiest life.