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Just how safe is heat not burn?

Heat not burn safetyReading Time: 5 minutes

One of the things you’ll hear a lot from anti-smokers is that 70% of smokers want to quit. If you actually talk to smokers you’ll probably hear a very different answer. Most of them don’t want to quit at all, because the truth is they enjoy smoking. They know they should quit, because smoking is undeniably bad for your health, but that’s not quite the same as actually wanting to. If scientists announced tomorrow that they’d got it all wrong and smoking was completely safe, you can bet nobody’d be interested in quitting. The appeal of Heat not Burn products is that, potentially, they can offer the enjoyment of smoking without most of the health risks. That raises a crucial question: How safe are HnB products really?

The general consensus is that heat not burn products are magnitudes safer than traditional cigarettes. There have been a lot of studies done on heat not burn products in recent years, a lot of it has been done by Philip Morris who manufacture the IQOS heat not burn device. The PMI Science website has a huge section on their own findings, the vast majority of them are peer reviewed studies too.

Early in 2018 BAT (British American Tobacco) who manufacture the Glo heat not burn device released details of a peer reviewed study looking into whether the vapour from their Glo device affected DNA.

Both BAT and Philip Morris have to get their studies peer reviewed because if they didn’t then people would simply say that they are being biased.

What is certain is that heat not burn products lie somewhere between e-cigarettes and traditional cigarettes on the harm scale. It is worth noting that the majority of damage caused to a smokers health is generated by the burning of the tobacco itself. As heat not burn only heats the tobacco to a vapour without actually burning the tobacco it will certainly be a lot safer than traditional cigarettes.

Most media reporting about cigarette smoke talks about nicotine – which isn’t actually a health issue at all – and tar. Some anti-smoking activists also distribute graphics listing a dozen or so ingredients of smoke, usually with alarming claims about what else they’re used in. “Formaldehyde – found in embalming fluid”, for example. Obviously they never mention that formaldehyde is also found in fruit, vegetables and everything else we eat, plus our own lungs actually manufacture it, but it’s quite effective as a scare tactic.

How many toxins?

For once, though, they’re actually underestimating the real issue. From a toxicology point of view cigarette smoke is nothing short of horrific. Scientists aren’t even sure how many different chemicals it actually contains – it’s at least 4,000, and could be well over twice that. More than 40 of these are known to cause cancer. Various sources say that anywhere between 200 and 400 of the others are toxic, but that doesn’t really mean much – anything is toxic in high enough doses.

Nowhere near as much is known about the chemistry of Heat not Burn vapour, because it hasn’t been studied much. As the products become more popular that will probably change rapidly, because researchers will start to take an interest. It’s likely a lot of their research will be used to create scaremongering headlines, as we’ve seen with e-cigarettes, but the actual data will be useful. However we can already say, very confidently, that the contents of the vapour will be a lot less harmful than cigarette smoke.

The whole point of Heat not Burn, as the name suggests, is that the tobacco isn’t being burned. It’s the combustion process that creates all the most dangerous chemicals, and by avoiding that heat not burn technology guarantees a much safer experience. A lot of the chemicals found in cigarette smoke are going to be in the vapour at much lower levels; a lot more won’t be there at all. Let’s look at some of the main chemicals found in smoke:


Nicotine gets a lot of bad press, but that’s mostly because the public associate it so strongly with smoking. Around half the British public – and nearly a quarter of doctors – think it’s nicotine that causes cancer in smokers. It isn’t. There’s no evidence at all that nicotine causes cancer in humans. There’s no evidence it causes heart disease either. When you inhale nicotine it causes a short-term rise in blood pressure, which doesn’t sound great, but long-term use actually lowers your blood pressure, which is good for your health. Nicotine also helps memory and concentration, can slow or halt age-related mental decline, reduces the symptoms of ulcerative colitis and is being investigated as a treatment for Alzheimer’s and Parkinson’s disease. It’s not “as addictive as heroin or cocaine” either. That claim is being made a lot, but all the actual research doesn’t back it up.

Don’t worry about nicotine.


Smokers are familiar with tar. It’s a sticky, oily brown substance that stains cigarette filters and leaves a yellowish deposit on anything that’s constantly exposed to smoke. The smoke itself is loaded with tiny droplets of it and most goes into your lungs. This is bad news. Despite what some anti-smoking sites say, cigarette tar is not the stuff that’s used on the roads. That’s bitumen, a by-product of oil refining. Instead it’s a mix of partly burned organic compounds from the tobacco, and it’s what contains most of the chemicals that cause cancer. It’s not clear how much tar is in the vapour from Heat not Burn, but if there’s any at all it probably isn’t much. The elimination of most or all of the tar slashes the cancer risk dramatically.

Carbon Monoxide

Although it doesn’t get much attention, carbon monoxide is probably the single most lethal component of cigarette smoke. It’s a gas produced when anything containing carbon is burned inefficiently, and it’s one of the most effective killers around.

Normally, haemoglobin molecules in your blood transport oxygen round your body – but carbon monoxide is far better at sticking to haemoglobin than oxygen is, so if you’re inhaling it your blood’s ability to carry oxygen is reduced. If you inhale enough you’ll lose consciousness and die – and one of the things that makes carbon monoxide so dangerous is that usually there are few symptoms, so victims don’t even notice they’re being poisoned. In smaller doses it forces your heart and lungs to work harder, putting stress on your circulatory system. This damages and stiffens arteries, and can lead to fatal heart disease.

Because carbon monoxide is a combustion product you won’t find it in HnB vapour. This probably makes an even more massive difference than the lack of tar.

Nothing to lose

So we might not know exactly how safe heat not burn is for a while, but just the fact there’s little or no tar, and no carbon dioxide, in the vapour means it’s definitely a lot safer than smoking and possibly as safe as e-cigarettes. If you’re already a smoker there’s a lot to gain, and nothing to lose, by switching to Heat not Burn.



This post is originally from February 2016 but has been updated as there has now been many many studies on heat not burn and other smoke-free products due to their increase in popularity.

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