Nicotine is the addictive substance present in tobacco plants. Benzoic acid can also be naturally found in plants, and is used commercially in dyes, perfumes, insect repellants, and food preservatives. Existing cell, animal, and medical studies counsel that glycerin and propylene glycol irritate the lining of the lungs. One small clinical examine 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 adjustments have been linked to asthma. Sign up for our Health Tip of the Day publication, and obtain every day tips that may allow you to reside your healthiest life.