We have also shown that nicotine e-cigarettes, cytisine, and varenicline appear to help more people quit than other products used to stop smoking. Nicotine replacement therapy appears to be almost as effective, but only when a patch is used alongside another form of nicotine replacement, such as gum or nasal spray.' This leaves nicotine e-cigarettes and combination nicotine replacement therapies as the two most effective stop-smoking aids available to most people. Using two types of nicotine replacement therapy (NRT) together, such as a nicotine patch plus a faster-acting NRT product like gum or lozenges, may be almost as effective as nicotine e-cigarettes, varenicline and cytisine. Our findings provide clear evidence of the effectiveness of nicotine e-cigarettes and combination nicotine replacement therapies to help people quit smoking.