The only realistic risk so far is addiction and a nicotine addiction doesn’t ruin lives. Other than that it’s marginally bad for the heart and so far atleast not carcinogenic.

As stated by a sibling comment, at least the carcinogenicity part isn't true. Unfortunately, even nicotine gum should be carcinogenic (and is of course not intended to be used for consumption besides of alleviating withdrawal effects).

Presence of the Carcinogen N′-Nitrosonornicotine in Saliva of E-cigarette Users: <https://pubs.acs.org/doi/10.1021/acs.chemrestox.8b00089>

Nicotine itself is carcinogenic in the mouth:

> Nicotine in tobacco can form carcinogenic tobacco-specific nitrosamines through a nitrosation reaction. This occurs mostly in the curing and processing of tobacco. However, nicotine in the mouth and stomach can react to form N-nitrosonornicotine, a known type 1 carcinogen, suggesting that consumption of non-tobacco forms of nicotine may still play a role in carcinogenesis