Nicotine is the addictive substance found in tobacco crops. Benzoic acid can be naturally present in vegetation, 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 liner of the lungs. One small scientific examine from 2018 that found that the compounds modified vapers’ sputum—the mucosal lining that covers the interior respiratory tract—to express totally different immune proteins. Some of those protein adjustments have been linked to bronchial asthma. Sign up for our Health Tip of the Day newsletter, and obtain daily suggestions that may assist you to reside your healthiest life.