Nicotine is the addictive substance present in tobacco plants. Benzoic acid can be naturally found in plants, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and clinical studies recommend that glycerin and propylene glycol irritate the liner of the lungs. One small medical research from 2018 that discovered that the compounds modified vapers’ sputum—the mucosal lining that covers the internal respiratory tract—to express totally different immune proteins. Some of these protein modifications have been linked to bronchial asthma. Sign up for our Health Tip of the Day e-newsletter, and receive every day tips that can allow you to reside your healthiest life.