The claim that eliquid contains formaldehyde is about as old as vaping itself. It’s echoed by tabloids and aspiring investigative journalists looking for a big scoop about something gaining popularity in modern society. It’s echoed by a few regulators, and a couple of mothers who worry that their kids are vaping out behind the estate, on Twitter.

Maybe it’s even echoed around inside your own head. Are you vaping formaldehyde? Is that a bad thing? Is it pickling your insides or leading you to an early death?

In part 1 of our impromptu exploration of vaping myths, we looked at whether coils are leaching toxic metals into your vape. Now we take on formaldehyde.

(Also, don’t read the title, it’s a spoiler alert. Wait, you already did?)

What is formaldehyde?

Formaldehyde can be pretty toxic to living creatures. Luckily, humans are good at breaking it down if ingested. In small quantities, in fact, it’s mostly just irritating.

However, if inhaled, and especially if inhaled continually over a long period of time, it starts messing with humans. Studies have shown that people exposed to formaldehyde in their day-to-day work—embalmers, for example—prove to be at a higher risk for some cancers like leukaemia and nose cancer.

Another group of people who inhale a lot of formaldehyde are smokers. Formaldehyde is emitted in the process of burning carbon compounds, like wood, petrol, and—you guessed it—tobacco.

But nothing’s actually burning in e-liquid, right? So we’re safe?

We’ll get around to that. But first, let’s roll the clock back to take a look at where this fear came from.

Formaldehyde in e-liquid

Back in 2014 and 2015, a couple of studies came out claiming that e-cigarettes produce not one, not two, not three, but fifteen (15!) times the amount of formaldehyde that cigarettes do.

Well, not quite. The truth is that a researcher at a press conference about a Japanese study (which found that e-cigarettes product between 13 and 807 times less formaldehyde than cigarettes) reported that one brand of e-cigarette they tested released 10 times as much formaldehyde as cigarettes when overheated.

The second study, in the New England Journal of Medicine, reported again that when e-cigarettes are overheated, they can produce higher formaldehyde levels than traditional tobacco.

So what gives?

The explanation

The levels of formaldehyde weren’t measured by people actually vaping—this would contaminate their vapour sample with whatever’s in the vape user’s mouth, and the whole study would be done with.

Instead, the test was undertaken with a vaping machine. And the machine wasn’t set to ‘recreational’ or ‘social’ vaping; it was set to ‘chain vape the living daylights out of this e-liquid’. Which is how they got it to overheat, and how they got it to produce any formaldehyde at all.

Of course, if they had used a human, they probably would never have reached that point, because of the dreaded dry hit. Before they got anywhere close to formaldehyde, the vape user would have started choking on their own lungs.

The real effect of vaping

These studies coincided with a couple of other studies on the effects of eliquid on formaldehyde presence in people’s bodies. One of them, funded by the Medicines and Healthcare products Regulatory Agency (MHRA) examined changes in levels of acrolein (a close relative of formaldehyde) in both smokers who switched to exclusively using e-cigarettes, as well as smokers who continued to smoke while also using e-liquids (so-called ‘dual users’).

Those who switched exclusively to e-cigarettes displayed a significant drop in acrolein levels, which, let’s be honest, was to be expected.

However, the dual users also saw their acrolein levels descend, even though they were still smoking. Public Health England explains:

“This was because they reduced their smoke intake as indexed by exhaled CO [carbon monoxide] levels. Normal vaping generated negligible aldehyde levels.

“Although e-liquid can be heated to a temperature which leads to a release of aldehydes, the resulting aerosol is aversive to vapers [that is, no one wants a dry hit] and so poses no health risk.”

In conclusion

There you have it. Your vape is not producing any dangerous levels of formaldehyde (or any other aldehyde for that matter), unless you’re regularly vaping dry hits—in which case, what’s the matter with you?

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