If you are a smoker looking to quit, then you should know that the largest study to-date, conducted by Cochrane, found high-certainty evidence that E-Cigarettes are more effective for quitting smoking than traditional nicotine replacement therapy, like nicotine patches and nicotine gum (9)
El Golli N, Rahali D, Jrad-Lamine A, Dallagi Y, Jallouli M, Bdiri Y, et al
This study was also carried out following the Helsinki Declaration of 1964 as well

Independent research found e-cigarette packaging nationwide is often misleading or even completely inaccurate on the products nicotine level.[2] Sometimes e-cigarette packages claim the device contains no nicotine, but when tested the product in fact contained high levels of the addictive and harmful substance.[3] Some studies compared JUUL pods to a pack of cigarettes, and the claim one pod was roughly equivalent to one pack of cigarettes.[4] However, the studies found the amount of nicotine varied dramatically from pod to pod, making any comparison loose at best.[5] JUULs popularity has decreased over the past several years, with brands like Vuse and Puff Bar increasing in sales, each with their own formulations.[6] An early e-cigarette study published in Nicotine & Tobacco Research compared different e-cigarette brands for 15 puffs and saw nicotine levels varying from 0.5 milligrams all the way up to 15.4 milligrams.[7] Newer e-cigarettes may also contain much larger e-liquid reserves, further clouding the calculations

[3] In California, it is described as growing especially in disturbed areas and along stream beds
Participants easily identified the flavor capsules on the pack and knew how they worked, as previously reported [ In our study, female young adults particularly stressed the contribution of capsules to product appeal