People are really out here thinking vaping isn't killing you : r confidentlyincorrect E cigarettes are likely to cause cancer, including in the lungs and mouth, according to a sweeping review of scientific evidence that challenges their positioning as a safer alternative to smoking. There is The microbiome in cancer Lin 2025 iMeta Wiley Online Library New study comes the closest yet to proving that e cigarettes aren't as dangerous as smoking Vapes and e cigarettes often contain nicotine, heavy metals, and carcinogensand can harm developing brains, affect mood and learning, and lead to lasting lung damage. Just one hit can start an addiction.