When e-cigs first came onto the market in 2008, vendors told customers that one pre-filled e-cig cartridge equalled 20 tobacco cigarettes.
This myth was soon exposed and done away with.
Today, responsible vendors will do their best to give customers an indication of equivalency, but this has never been an exact science as people vape and absorb nicotine at different rates. We also have to be aware that when we take the stated mg of nicotine from a tobacco cigarette and compare it to the stated mgs in e liquid, we are actually comparing apples to oranges. Why?
Tobacco cigarettes – the nicotine content stated on a packet of cigarettes is produced on a scale of nicotine being delivered in the body. This is known as yield.
The yield means that if you smoke a cigarette that has stated 1mg nicotine content, your body will pretty much receive that 1mg of nicotine. This figure though bears no resemblance to the amount of nicotine in dry weight that is in the actual cigarette. Put simply, manufacturers account for two factors in being able to state significantly lower ‘yield’ figures than the true contained nicotine content: an agreed average percentage of the maximum amount of smoke that can be produced by a fully burned cigarette which is inhaled, and the percentage of this inhaled nicotine that is actually absorbed by the body.
If you took a King Size cigarette for example, and worked out the dry weight nicotine content of said King Size cigarette, the dry weight nicotine of the complete packet of 20 King Size cigarettes, and then the dry weight nicotine content of 200 King Size cigarettes, what would you find?
The weight of the tobacco in the cigarette is in the region of a gram, and with the dry weight of nicotine being at 0.6 – 3.0 per cent of tobacco, each cigarette in the packet would contain between 6 and 30 mg of nicotine. After some modest research and with a median of 1.5 per cent dry weight of nicotine in cigarette tobacco, an average cigarette will contain 15 mg of nicotine, with a packet of 20 containing 300 mg of nicotine. As cigarettes are routinely sold in cartons of 10 packets, the sale of 3,000 mg of nicotine in a single carton is allowed.
Again, the nicotine stated on the side of a packet of cigarettes only refers to the amount of nicotine that will be delivered to the median user’s body – the yield, but the actual dry weight nicotine content will be far higher, in this example 15 mg per King Size cigarette.
Electronic cigarettes – 20 mg/ml of e liquid will tell you how much nicotine is in the liquid (much like the dry weight of nicotine in tobacco cigarettes), but it will not tell you how much nicotine is delivered to an individual’s system – the yield.
Looking at the nicotine absorption rates for smoking compared with vaping: smoking tobacco cigarettes is the fastest and most efficient way for an individual to get nicotine into their system. With vaping however, it takes longer, and, like smoking, you are not absorbing all the nicotine you inhale, as is shown in the chart below taken from Matt Gluggles blog.
The tmax above states the time taken for the nicotine to enter the blood stream, the Cmax is the concentration of nicotine delivered to an individual’s blood stream. Comparing that Cmax of a cigarette to that of an e-cig (ENDD) you see that the individual is absorbing 10 times less nicotine from vaping than smoking.
With the 16 mg ENDD you can see that from the 16 mg/ml nicotine content, (equivalent to the dry weight) only 1.3 ng/ml of nicotine concentration in the blood is produced, about 10 per cent of the nicotine concentration produced by a tobacco cigarette.
There is no easy way of directly comparing nicotine content of e-liquid with the yield of tobacco cigarettes, but during the above research it’s clear that a 16 mg/ml e-liquid gave the users just one tenth of the peak nicotine concentration provided by a “1.0 mg” tobacco cigarette. Perhaps it would therefore be fairer to label 16 mg/ml e-liquid as “0.1 mg cigarette equivalent”.
This raises an interesting question…
The revised TPD will continue to allow tobacco cigarettes to be sold in cartons containing 3,000 mg of dry weight of nicotine, with a yield of 200 mg of nicotine, yet the highest nicotine content proposed in the TPD for e-cigs is 20 mg/ml, in a bottle no larger than 10 mls, meaning 200 mg nicotine content at its highest. That is 3,000 mg versus 200 mg for a product that is several orders of magnitude less harmful.
We have to ask where is the level playing field, where is the rationality?
The more we look at the TPD, the more evident it is that it is about protecting the tobacco and pharmaceutical industries and nothing to do with public health. How else can this 3,000 mg of nicotine limit versus 200 mg be justified?
Finally, what about the policy makers in all of this? Whilst they have focussed all their attentions on the size and colour of a tobacco cigarette packet, they have paid no real attention to the labelling on the packet and what it means. We suspect that this is because they have no real understanding of nicotine and how it is absorbed into the system. That they did not have the courage to recognise this and seek expert advice is a shocking dereliction of duty and yet another example of the truly appalling way our elected representatives and their officials have gone about revising the TPD.
Although not relevant in this document, it is worth considering a smoking survey completed in 2001 that concludes the nicotine yield displayed on cigarette packs are misleading.
The survey concludes: “Current approaches to characterising tar and nicotine yields of cigarettes provide a simplistic guide to smokers’ exposure that is misleading to consumers and regulators alike and should be abandoned”