The rat squealed as I forced another drop of Halo American Red e-liquid into its mouth.
“3 milligrams, and still alive,” I reported grimly to my smoking hot lab assistant…
While strictly speaking you’d need experiments to see how much e-liquid it would take to kill, that’s not really us, so we’re going to have to rely on a survey of the science.
But first, a story…
A few months ago his brother Gustave had been enjoying a meal at Bocarne’s house. He was not expecting his brother the count, to seize him by the throat.
He pulled at his brother’s hand, biting and scratching, but the Count forced Gustave, already weakened by illness, to open his mouth while his wife poured in a liquid distilled from two phials of nicotine – liquid he had already tested on the household animals.
All potential witnesses had been cleared from the room, but a maid reported hearing cries. As she rushed towards the room, she ran into the Count rushing out the other way. Detection of the nicotine provided the basis for modern forensic science, but it’s also an example of how poisonous pure nicotine can be.
How much nicotine would it take to kill you?
As the story shows, nicotine is poisonous, and if you take enough of it, it will kill you.
But just how much is enough?
Published guidelines generally claim that around 30-60 mg, or 0.8mg/kilo, would be enough to kill a person, leading to warnings that just five cigarettes could kill an adult.
To put this in perspective it takes 3.3mg of nicotine per kilo to kill a mouse, and more than 50mg of nicotine per kilo to kill a rat.
Mice aren’t the greatest model to use, but that’s still some difference!
A cigarette contains about 10 mg of nicotine. According to published guidelines, this would mean eating four or five cigarettes would have about a 50 % chance of killing you. You’d have to smoke a lot more than this, since you only get a small amount of the nicotine in a cigarette when you smoke.
In fact, there have also been reports of attempted suicides which failed despite a much higher concentration of nicotine (although vomiting probably helped). In one especially shocking example, somebody survived consuming 4 g (i.e. 4,000 mg) of pure nicotine. This is over 60 times more than the widely-cited toxic dose.
These strange inconsistencies spurred one scientist to investigate further…
Hey! Let’s find out if nicotine is dangerous by testing it on ourselves…
Over 150 years ago two researchers, Dworzack and Heinrich, decided to find out if nicotine was dangerous – by taking it themselves. After taking 1-4mg of nicotine they claimed symptoms including:
…headache, dizziness, numbness, cloudy vision and hearing, light sensitivity, anxiety, dryness of the throat, coldness of the limbs, ructus [belch], flatulence, nausea, vomiting and rectal tenesmus. Respiration was accelerated and labored, pulse rate increased initially, and rose directly with the increasing dose; but later rose and fell erratically. After 45 min the experimenters lost consciousness. One of them suffered clonic seizures for 2 h, particularly of the respiratory muscles, also tremors of the limbs and shivering over the whole body. After the initial recovery, feelings of exhaustion, drowsiness and bleakness remained for 3 days.
This report is quite bizarre.
Consuming 1 to 4 mg of nicotine is like smoking a few cigarettes in quick succession. You’d expect to feel nauseous, but losing consciousness and suffering seizures is a very extreme reaction, to say the least. It’s not really clear what actually happened, but either the reactions were exaggerated or they must have messed up the dosage and ended up consuming a lot more than a few mg.
This questionable report might have been ignored if it wasn’t for respected German toxicologist Rudolf Kobert, who used the findings in his chapter on nicotine for his textbook of intoxicants. In the chapter, he wrote:
“The lethal dose of pure nicotine is also difficult to determine, because it easily decomposes a bit and, on the other hand, mostly contains more or less water; however, in accordance with the severe symptoms evoked in several experimenters by 0.002–0.004 g it is certainly not going to be higher than 0.06 g.”
Strangely enough, the scientist reporting the study ignored another pharmacologist, Reid, who took 7mg of nicotine but only experienced very mild symptoms.
Yet, according to researcher Bernd Mayer, these dubious experiments by two nineteenth century scientists are the basis for 21st century warnings on nicotine.
Until Mayer traced back through the “circular and often misleading references,” nobody really knew where the information came from. But that didn’t stop it from being widely repeated!
So What’s The Real Limit
More recent studies have shown that intravenous injection of 5mg of nicotine (equivalent to a 25 mg dose taken orally) lead to only mild symptoms of nausea and coughing.
Post mortem examinations of people who have died from nicotine poisoning suggest that lethal doses of nicotine could be 20 times higher than the 6o mg limit. (As nicotine breaks down rapidly after you die, the lethal dose could well be higher than that.)
Meanwhile, at his presentation at the 2013 ECigaretteSummmit, Jacques Le Houezec pointed out that deaths from nicotine poisoning are rare, even in children. (Update: Jacques discussed this further with me in this interview here.)
Out of 10 cases where children had had nicotine poisoning, not one had died.
And in 51 cases of ingestion of cigarettes or gum among children aged 5 months to 9 years, there had been no fatalities reported.
In the US, there is quite detailed data on e-liquid poisonings and how they turn out. The 2015 report (p147) from the American Association of Poison Control Centers shows that there were 3,613 calls about e-cigarette liquids or devices in total, but only 5 led to major issues.
In 103 cases, there were moderately serious outcomes. But overall the vast majority (about 97 % of cases) either led to no consequences or only minor ones. Nobody died.
“Nicotine is not nearly as dangerous as previously reported,” argued Dr Jacques Le Houezec, suggesting that a conservative estimate of a lethal dose would be at least 20 times higher than the current 6o mg limit.
He also pointed out that after two years of low exposure to nicotine for 20 hours a day, the only effect on lab rats had been weight loss.
Caution: This is a massive increase in estimate for the lethal dose of nicotine, and is obviously not based on a clinical trial. Please continue to be very cautious when you handle nicotine.
So how much eliquid would you have to vape before you died?
It’s impossible to provide exact figures.
As our resident pharmacologist, Gwyn Taylor, pointed out to me very firmly, you can’t give 100 people lethal amounts of nicotine and then work out what the average lethal dose is. (If you applied for our lab trial, please note the trial has now been cancelled.)
(Note to murderers – you also need to make sure that your victim is not a smoker or a vaper. Because of our higher tolerance levels, you’ll need a lot more to nicotine to kill a smoker/vaper than someone who doesn’t use nicotine.)
So to play safe, let’s use current limits. These are ridiculously over-the-top, but it will get the point across anyway.
We’ve already seen that current warnings are that the nicotine in just five cigarettes could kill you. However, when you smoke a cigarette you only absorb about 1-1.5mg of nicotine, so to reach the 30-60 mg limit you would actually have to smoke in the region of 20-60 cigarettes (or around 1200 cigarettes using Houezec’s estimates.)
We know that when you vape, your body absorbs slightly less nicotine than it does from a cigarette, so you’d have to vape more than the equivalent of 20-60 cigarettes. And you’d have to do that pretty quickly!
Nicotine has a half life of two hours, so half of the nicotine you’ve consumed will have been processed two hours later. In other words, by the time you smoked even a pack of cigarettes or vaped a few mls of e-liquid, you would probably have metabolised and excreted most of the nicotine.
And the half life of nicotine is perfectly illustrated by Shamans’ use of nicotine….
Shamans, Spirit World, And Nicotine Half Life
Huge quantities of tobacco smoke filled the hut, stinging the eyes of everyone huddled inside.
In the centre of the hut a shaman sat cross legged, a pipe in his hands. He inhaled deeply again and again, until his eyes rolled backed in his head and he slumped to the floor, senseless.
The shaman appeared lifeless to his audience, but his mind was active, heading off on a journey to the spirit world.
It would be the next day before he returned back to life…
As Jacques explained, Shaman’s would use huge quantities of nicotine until they appeared to be dead. But the next day, thanks to nicotine’s half life, they would be completely back to normal – an event that appeared miraculous to the Shaman’s followers.
(Check out Shamanism and Tobacco for more fascinating information on this topic!)
Two More Reasons Why Vaping Isn’t Going to Kill you
Even if you managed to overcome these hurdles, vaping isn’t likely to kill you.
1. The first sign of nicotine poisoning is nausea. And when smokers and vapers start to feel sick, they stop using nicotine.
2. In addition, scientists have found that smokers take just the right amount of nicotine for what they need (in scientific terms, they ‘self-titrate’).
Nicotine is unique in that it can both stimulate and relax, and smokers/vapers take the right amount to do whatever they need it to. If you take a little, it behaves as a stimulant. But if you take more, it helps you relax.
But it also means that smokers stop before taking too much.
An example Dr Houezec gave is smokers who use nicotine patches. Many smokers who use nicotine patches continue to use cigarettes, but they change how they smoke or smoke fewer cigarettes so that they do not take in too much nicotine.
Unfortunately, drinking a 15ml bottle of 24 mg e-liquid is another matter.
That’s because 24mg is per millilitre rather than per bottle. So a 15 ml bottle would contain 360mg of nicotine, which would kill you under current guidelines but probably not under revised estimates.
Children are much more vulnerable than adults, because they weigh a lot less. So it’s essential to ensure that your e-liquid has a child proof cap on it, and is kept out of reach of children.
(As I know from experience, that’s not always easy when they reaching the climbing stage).
Update: Do note that since this post was written, the maximum nicotine strength is now 2%, and the maximum bottle size of nicotine containing e-liquid is 10ml, which might go someway to restoring those still nervous about e-liquid poisonings.
What happens if you get e-liquid on your skin?
When two gardeners decided to paint a peach tree with 2.7% nicotine solution, they could have done it a bit more tidily.
In the process of painting the tree, they managed to splash the solution on their face, their hands and on their forearms.
The gardeners got moderate nicotine poisoning, which is probably due to the length of the exposure as well as the quantity.
The skin acts as an effective barrier to nicotine, but the longer you leave nicotine on your skin the more will be absorbed, so it’s obviously important to clean spills quickly.
The authors used an 8 mg/ml e-liquid, and found that each square centimetre of skin exposed absorbed about 0.005 mg of nicotine per hour.
If you spilled e-liquid on your entire palm, you’d absorb about 0.5 mg per hour. Higher-nicotine e-liquid would lead to more being absorbed, but it’s clear from this that the absolute amount would still be small.
With this in mind, it is likely to take a large quantity of e-liquid exposure – left there for a long time – for there to be any risks of nicotine poisoning. Just don’t paint your peach tree with it!
Nicotine – It’s Not All Bad
Whatever the lethal dose of nicotine, it needs to be treated with respect. But it’s not all bad.
The truth is that the risk of nicotine poisoning from e-liquid – despite being something we should take seriously – really pales in comparison to the substantial benefits of providing smokers with a safer source of nicotine.
Check out Nicotine in Electronic Cigarettes: 10 Facts All Users Should Know for more fascinating information about the drug!
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