Nicotine is the addictive substance found in tobacco crops. Benzoic acid can be naturally present in crops, and is used commercially in dyes, perfumes, insect repellants, and meals preservatives. Existing cell, animal, and medical studies suggest that glycerin and propylene glycol irritate the lining of the lungs. One small clinical study from 2018 that discovered that the compounds changed vapers’ sputum—the mucosal lining that covers the internal respiratory tract—to precise totally different immune proteins. Some of those protein changes have been linked to bronchial asthma. Sign up for our Health Tip of the Day e-newsletter, and obtain day by day suggestions that will assist you to live your healthiest life.