What's Actually in Your Vape: A Complete Chemical Breakdown 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 What Ingredients Are In An E Liquid? High concentrations of flavor chemicals are present in electronic cigarette refill fluids Scientific Reports Vape juice contains a long list of chemicals, many of which aren't even listed on the packaging. Testing has also shown that vapes labelled "nicotine free" can have high nicotine levels.