How much nicotine do we get from e-cigarettes?
The question of how much nicotine is delivered to users of e-cigarettes is one that you might have thought had been solved years ago. Yet the reality is that there's never really been much consensus on this issue. In fact, the question of how much nicotine cigarettes deliver to their users is one that researchers still argue over.
The reason for all this uncertainty is one of methodology. Regarding cigarettes, it was assumed that if you set up a machine to mimic smokers (the ISO methodology), and analyze the smoke that the machine 'smokes', you'd have a pretty good approximation of how much nicotine real smokers were absorbing. Sadly, the machines did a poor job of mimicking smokers and probably hugely underestimated the real numbers.
A similar story occurred with e-cigarettes, when Eissenberg and colleagues found that little nicotine is absorbed by vapers. Except that they didn't use vapers in the study, they used smokers, and they did a puff-for-puff comparison with cigarettes. As any vaper worth his or her salt knows, you don't vape like you smoke - so the study came back with results that are irrelevant to real-world use (although that doesn't mean it wasn't worth doing).
Now, however, we are a step closer to knowing exactly how much nicotine we do get from e-cigarettes. Dr. Konstantinos Farsalinos and colleagues have just published their in-depth study (full text) which analysed 45 experienced e-cigarette users and 35 smoking controls. They looked at several measures, including the puff duration and number of puffs taken over a given time-frame from users puffing on a eg0/tank setup. They found that, using the 9mg/ml liquid provided in the test, vapers were consuming around .5mg of nicotine in 5 minutes, and 1.6mg over 20 minutes.
Scaling this figure up to a 20mg solution (as used by many vapers), Farsalinos concludes that 1mg per 5 mins, and 4 mg per 20 mins of nicotine would be consumed. In other words, then, this puts somewhat paid to the notion that e-cigs do not provide substantial amounts of nicotine to the user. But it does more than that - in establishing a precise figure for the amount of nicotine delivered to the user, it flatly contradicts the European Commission Tobacco Product Directive that 4mg/ml liquids are equivalent to NRT.
This last point is very important, because the TPD will remove from the market any e-cigarette product that outperforms NRT based on nicotine delivery. The commissioners have stated that they wish to create a level-playing field (with products that don't work), and this is based on faulty experimental evidence. If it was based on any evidence at all. This evidence shows that 20 minutes of puffing on 20mg/ml liquid provides the user with almost exactly the same amount of nicotine as 20 minutes puffing on a Nicotrol Inhaler.
As Dr. Farsolinos has pointed out, there are more questions to be answered. For instance, this experiment measured how much nicotine was delivered to the user, but it did not measure how much nicotine is absorbed (and associated measures such as the speed of absorption). Indeed, it is possible that nicotine absorption is much lower compared to cigarettes, indicating that smokers will need even more e-liquid or higher strength e-liquid to satisfy their nicotine needs.
Another great benefit of this study is that future research now must take this sort of methodology seriously. Any paper submitted without having considered exactly how vapers use the product should be rejected by the journal editors. Any paper that is released using dated methodology will be fiercely criticized, and those people using such studies to bolster their ideology will be on the backfoot when it comes to explaining themselves.blog comments powered by Disqus