Nicotine is the addictive substance present in tobacco crops. Benzoic acid is also naturally present in crops, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and medical studies counsel that glycerin and propylene glycol irritate the lining of the lungs. One small scientific study from 2018 that found that the compounds changed vapers’ sputum—the mucosal lining that covers the interior respiratory tract—to precise totally different immune proteins. Some of these protein adjustments have been linked to asthma. Sign up for our Health Tip of the Day newsletter, and obtain every day suggestions that will assist you to reside your healthiest life.