Non Nicotine Vape: A Safer Smoking Alternative What's really inside a vape? Many people think vaping is just flavored vapor, but the aerosol from e cigarettes can contain harmful substances that go straight into the lungs. According to the Nicotine Vapes: the Chemicals They Contain, What They Can Do to You Business Insider Do you know what you're vaping? Propylene glycol (PG) and vegetable glycerin (VG) are the main liquids in vapes. When heated, these chemicals turn toxic and aren't safe to breathe.