Honestly I’m not really sure about that. What I’ve seen on the idea of damage to children usually has the caveat of “more study is needed”, but of course nobody wants to subject children to such a study on purpose. On the other hand, I haven’t seen any studies yet that concluded long-term use in adults would cause any permanent damage. I suspect there could be outlying cases of extremely heavy usage but in moderation it so far appears to be perfectly safe.