Teen vaping is changing fast — and not in a good way. A large national study found that more adolescents are vaping THC, CBD, and especially synthetic cannabinoids, which are often unregulated and far more dangerous. Even more troubling, many teens don’t know what’s in their vape pens at all. Researchers also found that girls are now more likely than boys to vape these substances. As these mysterious and risky chemicals gain popularity, scientists are sounding the alarm about the urgent need for better education, regulation, and awareness.