Kids who vape and use other forms of e-cigarettes are likely to try more harmful tobacco products like regular cigarettes, but e-cigarettes do hold some promise for helping adults quit.

That’s according to the National Academies of Science, Engineering and Medicine, which published a comprehensive public health review of more than 800 studies on e-cigarettes on Tuesday.

“There is conclusive evidence that most products emit a variety of potentially toxic substances. However the number and intensity is highly variable,” says David Eaton, who heads the committee that wrote the report. He is also the dean and vice provost of the graduate school of the University of Washington, Seattle.