The Diacetyl Debate: Panic, Controversy and the Need for Transparency

Although the facts on diacetyl in vape juice are debatable, the evidence still paints a consistent picture: it probably isn’t something you should be inhaling. That’s the plain and simple truth.

But the issue for vapers themselves is even less clear. Even if the amounts detected in vapor do pose a risk, the amounts in cigarette smoke are much higher, so switching to vaping is still the safer option. Additionally, we do many things – drinking alcohol, for example – which aren’t completely safe, because we enjoy doing them. So if you enjoy diacetyl-containing flavors, is it really such a big deal? Are there other harmful chemicals in vaping?

The diacetyl issue is also an important one for the industry as a whole. Have e-juice companies really done enough to remove diacetyl from their liquids, and have they been up-front enough with vapers about the issue? Should we just label juices containing diacetyl, or remove it entirely?

The facts on the risks of diacetyl might be fairly clear – even if not totally settled – but the debate among vapers is thorny and complex.

The Big Question: Do You Vape Diacetyl-Containing Juice?

 We’ve spoken to a selection of prominent vapers, reviewers and advocates about the issue of diacetyl, and we put a simple – but crucial – question to them: do you vape e-liquids with diacetyl?

Grimm Green

“As a general rule I try to stay away from juices with diacetyl. If we’re talking about ‘harm reduction’ then making the juices as safe as possible certainly falls into that mindset. I have a few (maybe 2 – 3) juices that I know contain trace amounts of diacetyl and I vape them on a regular basis. I feel as an adult I can decide what level of safety I’m responsible for vaping at.” – Nick Green (GrimmGreen / NamberJuice)

Michelle Harnden

“I personally would not choose to make an e-liquid I know to have diacetyl my all day vape. However, I would also not completely disregard an e-liquid just because diacetyl is present.” – Michelle Harnden (Mt. Baker Vapor)

James Dunworth

“Personally, I wouldn’t have a problem vaping a juice which contains diacetyl from time to time. However, I would avoid vaping it on a daily basis.” – James Dunworth (E-Cigarette Direct)

Daniel Hall

“I have taken the time to research the diacetyl issue and have reached a personal conclusion that a possible small amount is nowhere near as dangerous as the levels I subjected myself to the entire time I was smoking.

I don’t vape because it is 100% safe, but thousands of times safer than smoking.” – Daniel Hall (Guide to Vaping)

Russ  Wishtart

“I would never choose to vape a liquid with diacetyl or acetyl propionyl, because I can get a liquid that tastes just as good without those chemicals, so why take the risk when you don’t have to?” – Russ Wishtart (Click, Bang!)

The Vapor Chronicals

“I do vape liquid containing diacetyl and until I see more legitimate and concrete evidence of its potential harms then I will continue doing so. I also eat steak, speed, use spray paint, and drive in rush hour traffic among other at risk things.” – Brian (The Vapor Chronicles)

Morton Moe

“It depends on the amount I guess. I agree with Dr. Farsalinos that this is an avoidable risk, but I’d accept low levels that could just be contamination.” – Morten Moe (the Vaping Giraffe)

Chris from Vaping360

“If I can knowingly avoid e-liquids with high levels of diacetyl then I will. I usually vape e-liquids that have been tested to be “free” of diacetyl or contain very little amounts of diacetyl. Why put myself at any unnecessary risk if I don’t have to? If I do vape e-liquids with diacetyl in them then I don’t want them to be any higher than low double digits of parts per million.” – Chris Kendell (Vaping360)

So while there are some who come down a little harder on both sides, the predominant viewpoint from the vapers we spoke to is that some diacetyl on occasion is OK, but regular, and particularly daily vaping of diacetyl juices is more of a cause for concern.

Is the Issue Being Over-Hyped, or Should We Be Worried?

One thing that goes without saying is that the concern about diacetyl has broken through into the mainstream recently, thanks to the latest study and the ensuing media panic. Usually, vapers are pretty united in decrying these periodic scare-fests as overblown, ill-supported and potentially damaging, but with diacetyl it isn’t quite so easy to dismiss. Are the media right this time? Should vapers be worried about diacetyl?

Many of the vapers we spoke to do think the concern is being over-hyped:

Grimm Green

“Truly and honestly I believe it’s being exaggerated. […] For some reason when the Diacetyl issue arose a number of years ago, people just went bananas. Vendors were getting called out and publicly ridiculed for having even trace amounts of diacetyl in their liquids.

If you really look at the numbers and cases of popcorn lung, the odds of the trace amounts of diacetyl in certain liquids having a negative impact on our respiratory system is slim.” – Nick “Grimm” Green (GrimmGreen / NamberJuice)

But others argue that while it’s being exaggerated a little, there is still genuine uncertainty and potential risk lurking behind the scaremongering headlines:

Russ  Wishtart

“Yes, diacetyl and acetyl propionyl are a potential risk, at certain levels they can certainly be very dangerous, but does that mean that a liquid that has under 100 ppm is going to give you popcorn lung? No it probably won’t, unless you’re vaping a liter of it a day. But are there liquids out there that have over 2,000 ppm? Yes, and people who are vaping 15 ml of it a day at high wattage are exposing themselves to significant risk.” – Russ Wishtart (Click, Bang!)

Others, like Michelle Harnden from Mt. Baker Vapor, point out that while the issue is overblown in terms of the effect on smokers and vapers, it’s important to remember that the issue is much more significant for non-smokers considering vaping:

Michelle Harnden

“The issue is a realistic comparison. For smokers who have been smoking for years, very few know that there is more diacetyl in a traditional cigarette than the majority of the e-liquids tested. However, I don’t believe any non-smoker should consider vaping, and particularly vaping e-liquid with diacetyl. If you aren’t already polluting your body, why start now?” –Michelle Harnden (Mt. Baker Vapor)

Michelle’s point about the difference between cigarettes and e-cigarettes in terms of diacetyl content is crucial for most vapers. We’re replacing smoking with vaping, after all. While Michelle makes an important point for non-smokers, for smokers and ex-smoking vapers, surely the comparison with cigarettes is the only thing that really matters?

Diacetyl as an Avoidable Risk

diacetyl risks

Those on the more anti-diacetyl side of the issue can be summed up neatly by Dr. Farsalinos’ comment in his study that diacetyl represents an “avoidable risk” for vapers. We can have delicious juices that don’t contain diacetyl, so why would you take the risk rather than just enjoy other flavors?

Morten Moe from the Vaping Giraffe puts the opposite case forward very well, balancing the admitted exaggerations of the risk with the core point from many vapers’ perspective:

Morton Moe

“I don’t believe we will see many vapers getting diagnosed with popcorn lung, at least if the industry take their responsibility seriously and doesn’t put this in knowingly. […] That being said, it’s important to keep focusing on reducing harm as much as possible, and as I said I agree with Dr. Farsalinos on this one: diacetyl and acetyl propionyl are avoidable risks that we don’t need to take.” – Morten Moe (the Vaping Giraffe)

This quote really captures what’s at the heart of the legitimate concern about diacetyl in e-juice. Vaping is all about harm reduction, and while reducing risk in comparison to smoking is the most important thing, there’s really no need to stop there. E-juice mixers have a whole world of flavors at their disposal: from tobacco through to exotic fruits and delicately-crafted desserts, so is avoiding a couple of flavorings really that big a deal?

The key is that the decision to add diacetyl to an e-juice is a decision to make something more dangerous. Any e-liquid will carry some risks, but taking that base formula and adding something you know is harmful when inhaled should be unthinkable. 

Why The Controversy? It’s Really About Transparency

diacetyl good or bad

There may be some disagreement about how worried vapers should about diacetyl, but it seems that the vapers we spoke to agree about the core points. The question then becomes: why does it cause so much controversy and debate within the community?

Morton Moe

“Well, some people defend vaping and everything about it whatever it takes, and they might feel that this issue is causing bad publicity for vaping. For others it’s more important that we make vaping as safe as possible, so we should avoid these risks… just because we can. It might turn out that the levels of diacetyl we’re talking about is harmless and no-one will ever get popcorn lung from vaping, but I don’t think we can conclude with that just yet. (Can’t believe I just said that, that’s the ANTZ’ mantra)” – Morten Moe (the Vaping Giraffe)

This uncertainty is likely a big part of why the topic of diacetyl generates so much debate, as well as the differing views on the level of harm reduction we should be aiming for – should we make vaping as safe as possible, or is safer than smoking good enough?

On this point, Brian from the Vapor Chronicles has a key insight:

The Vapor Chronicals

“Now that we have found freedom from polluting ourselves daily we are reinvigorated and health conscious. Many of us become much more involved and concerned with our health.” Brian (the Vapor Chronicles)

One thing we all have in common as vapers is that we once did something that is unilaterally, unavoidably bad for you, but now we’ve made a decision to reduce our risk, our level of concern about even smaller risks has increased. For anyone trying to maximize their reduction in risk, diacetyl is definitely an unwelcome addition in e-liquid. But the debate exists because not everyone is equally worried about these small risks.

This is why the issue of transparency from e-liquid mixers – so that you at least know the risks that you are taking – was identified by James and Daniel as one of the central causes of the disagreement.

James Dunworth

“I think the online vaping community as a whole is quite well informed. The problem is that vapers often don’t know if an e-liquid has diacetyl in. That’s been compounded by some companies claiming e-liquid is diacetyl free when it isn’t. So, it’s an issue of transparency.” – James Dunworth (E-Cigarette Direct)

Daniel Hall

“The division within the community is no worse when it comes to diacetyl than people arguing over who makes the best RDA, honestly.

The division didn’t arise from e-liquids containing diacetyl, but from companies claiming they were ‘clean’ and then being caught in what was perceived as a lie.” – Daniel Hall (Guide to Vaping)

Putting all of this together, the concern about diacetyl really comes from an understandable desire to not be in the dark about the issue.

We might have to infer the likely risks of vaping diacetyl from other evidence as best we can (which Carl V. Phillips called “heroic guesses” in our companion post), but we’re happy to do that, on the whole. Different vapers might come to different conclusions, but as long as we know what risk we’re taking, we wouldn’t really cause a big fuss about it. So, perhaps, the spotlight in this debate should be firmly on the industry.

Has the Industry Dealt With the Diacetyl Issue Well Enough?

Imagine you’re making a product that people are going to inhale. They’ll be taking what you’ve created, vaporizing it and putting it directly into their lungs. Any ethical retailer will immediately recognize this as a responsibility. The question is: how far does this responsibility go?

Arguably, as well as taking care in more obvious ways (not sneezing into an open batch, for example), you should take care to ensure you aren’t putting anything potentially dangerous in your juice. You should research potential issues and do everything you can to make sure that your product isn’t needlessly dangerous.

The relevance to the diacetyl issue is clear: it’s been known that diacetyl poses potential risks for inhalation since around 2000. At this time, modern e-cigs were barely a glint in inventor Hon Lik’s eye.

When the issue started to gain traction, there were some very positive moves from the industry, and some of the vapers we spoke to emphasized this:

Michelle Harnden

“I believe our industry has responded extremely well. Naturally, as studies show this could be a negative issue in vaping, the majority of the industry responded by removing and/or notifying their customers of the presence of diacetyl in their products.” – Michelle Harnden (Mt. Baker Vapor)

Daniel Hall

“Initially, as the idea that the deliberate addition of these substances was a bad idea unfolded, the industry responded by looking for alternate sources that were diacetyl free. The community made the demand and the majority of companies did what they could to fix the situation.” – Daniel Hall (Guide to Vaping)

But there is another side to the story. The issue was known about very early on, but research from years later provides a strong indication that it continued to be a problem.

A post on the E-Cigarette Forum from 2008 raised the issue with diacetyl in e-liquid specifically. This is before vaping really took off, so most e-juice mixers entering the industry had this information available to them, not only from more general sources, but from an e-cigarette-specific site.

The issue was raised several times (in several places) in the following years. There’s a post on the e-cig subreddit dated 2011 detailing the issue and listing flavorings known to contain diacetyl.

However, when Dr. Farsalinos conducted his study in 2014, almost three-quarters of tested liquids contained diacetyl, even ones where they clearly stated that diacetyl wasn’t in their juice. Last year, when the most recent diacetyl study was conducted, there was still diacetyl in a lot of juices. These may have all been sweet juices that had the potential to contain diacetyl (rather than a random sample of all juices), but in both cases diacetyl was present in the majority.

The remainder of the vapers we spoke to had more reservations about the industry’s response. While they praised the companies who dealt with things well, they draw attention to some of the less-than-ideal behavior of some companies:

Chris from Vaping360

“This is a difficult question, but on the whole I feel proud of our industry for doing its best to try and cater to all types of vapers. We at Vaping360 see many diketone test results (for our liquid reviews), so I know there are a lots of liquid manufacturers now trying to give their customers a choice. However, having said that I think there are still many e-liquid vendors that need be doing more. Vapers have the right to know what they are vaping and what levels of diketones are in their e-liquid.” – Chris Kendell (Vaping360)

Grimm Green

“Vendors have lied about having clean lab results, vendors have withheld their lab results from the public, and there have even been times where the lab tests themselves have been proven to be not quite as accurate as everyone thought. Multiple tests on the same batch of juice, from the same lab have yielded many different results.” – Nick “Grimm” Green (GrimmGreen / NamberJuice)

James Dunworth

“Some companies have reacted fantastically, by testing their e-liquids and publishing the results. Others haven’t reacted so well! For example, some companies that have been exposed as using diacetyl have responded with threats of litigation.” – James Dunworth (E-Cigarette Direct)

Russ  Wishtart

“As a whole [the industry has dealt with the problem] very poorly. […] Now some – I would say a minority of the companies – are taking the issue seriously and have made changes, so that’s good. But I think that the majority of companies that have been using these chemicals have not done anything, and it hasn’t hurt them at all, unfortunately. It’s hurt their customers in terms of health, but it hasn’t hurt them.” – Russ Wishtart (Click, Bang!)

Again, from most of the vapers we’ve spoken to, the issue isn’t necessarily with the possible health impacts of vaping diacetyl-containing juice, but with how the companies respond to requests from the community. Simply ignoring the issue – neither changing anything nor conducting tests – or even worse, pursuing litigation against those who do show test results is a guaranteed way to annoy vapers.

“Diacetyl-Free” Juices That Contain Diacetyl – Are Flavoring Companies to Blame?   Diacetyl-ecigarette-eliquid

One of the biggest issues is the perceived deception from some companies, largely due to the disturbing trend of juices that claim “no diacetyl” being found to contain it when testing is conducted. But is it really deception? After all, there’s a chance that the companies checked with their flavoring supplier but were given incorrect information.

Additionally, as Chris Kendell from Vaping360 suggests, in the early days of the vaping industry, the lack of awareness of what exactly diacetyl is and how it might get into a liquid could have been an issue:

Chris from Vaping360

“Originally, the big issue was that vendors thought diacetyl was an added-ingredient, so because they knew they never reached for a flavor called ‘diacetyl,’ they boldly stated, “Our liquids do not contain any diacetyl!” But it’s not like sweetener or just another flavoring. It’s in some of the base flavorings themselves, it can be formed from the combination of other flavorings (that may have not individually even had diketones), and it can also develop from other compounds in flavorings (like acetoin).” – Chris Kendell (Vaping360)

James Dunworth from E-Cigarette Direct gave an excellent, detailed response that covers most of the possible reasons diacetyl may be detected despite assurances to the contrary:

James Dunworth

“I think there are a number of reasons.

Flavor houses can make mistakes. So, sometimes they will sell a flavor as diacetyl free, but in fact it does contain diacetyl. The diacetyl won’t be discovered unless a lab then tests the e-liquid.

What’s more, even though diacetyl isn’t added, there is nothing to say that the individual molecules in the flavorings won’t bond together to create it. This is especially likely when multiple flavor concentrates are being mixed together. In this instance, there is a wider range of molecules available to potentially create these unwanted compounds.

This occurs unknowingly most of the time, and it’s often in minute amounts when it does, but this is why we have to test our finished mix and not the flavorings themselves.

I’ve also heard reports of testing issues in the US. Some companies have told us they have sent the same e-liquid to different testing companies, and had different results back.

At one point there was a lack of awareness amongst some e-liquid companies. Some were just not aware of the concerns around using diacetyl (or other known compounds of concern).

Finally, given human nature, I am sure there are some companies (hopefully not many!) who do not think it is a priority to test e-liquid and inform customers if it contains diacetyl.” – James Dunworth (E-Cigarette Direct)

GrimmGreen also points out that differences in the amount of diacetyl that can be detected in tests may be responsible:

Grimm Green

“I think ultimately it’s a case of what constitutes ‘containing’ diacetyl. For example, if vendor A has a 0.007 ppm (just made that level up) diacetyl tolerance. But the flavor company has a 0.009 ppm diacetyl tolerance. Then the flavor company believes their flavors to be diacetyl free, but when tested as a liquid from a vendor it would come up higher because the vendor or manufacturer would be using a flavor that they believe to be diacetyl free.” Nick “Grimm” Green (GrimmGreen / NamberJuice)

Additionally, it’s worth pointing out – as mentioned in the companion post to this one – that acetoin (an alternate buttery flavoring) is often contaminated with small amounts of diacetyl as a result of the production process. This is another possible reason “diacetyl-free” juices may be found to contain it.

Overall, the consensus from the vapers and juice mixers we spoke to is that the flavoring companies really can’t take too much of the blame. The comment from Russ Wishtart really gets to the core of why:

Russ  Wishtart

“You have to understand that most of the flavoring companies are making flavors that are used in thousands of products that have nothing to do with vaping. […] All they really need to do is say ‘these products are not made for inhalation.’ As far as a flavoring company is concerned, that is where their responsibility begins and ends.

And that point, it is incumbent upon the e-liquid manufacturer to know what’s in them, and they may have to spend their own money to test it if the flavoring company doesn’t provide it. It’s completely on the e-liquid manufacturer.” Russ Wishtart (Click, Bang!)

What Should We Do About Diacetyl: Full Disclosure or Removal?

As the industry moves forwards, the most important question is what should companies do about diacetyl? Should they stop using it altogether, or would full disclosure be suitable?

Nobody we spoke to advocated removal of all diacetyl from e-juice, but a major theme was that customers should be given full disclosure about what’s in their e-juice:

Grimm Green

“I’m of the mindset that an adult should be allowed to decide what they put in their body. If a juice vendor absolutely has to use diacetyl (which they don’t) they should completely inform any potential customers of its inclusion and the possible complications of vaping a juice with diacetyl.” – Nick Green (Grimm Green)

Chris from Vaping360

“I would never say that e-liquid should only be one way, but if a vendor knows that their liquids contain diketones, no matter the levels, I personally believe they should say so by posting their test results.” – Chris Kendell (Vaping360)

Michelle Harnden

“In my personal opinion, I don’t believe diacetyl should be used in e-liquid, but I also don’t believe it is a dangerous enough substance to be banned in the limited quantities that have been found. I’m proud to work for a company that has chosen to stop using it completely. For those who chose not to stop, I believe disclosure via third party testing is the proper response in respect to the requests of their consumers.” – Michelle Harnden (Mt. Baker Vapor) 

James Dunworth

“In our company, we’ve made the decision not to sell any e-liquid which has tested positive for diacetyl (and a number of other compounds of concern), and to only sell e-liquid which has been tested to a high standard. That’s a personal decision that is right for us and our customers, and is consistent with our mission statement.

It doesn’t imply judgment of other companies, and I think it’s fantastic that Vapor Shark have published the results of e-liquid testing so that informed vapers can make their own decisions.” – James Dunworth (E-Cigarette Direct)

How to Avoid Diacetyl

diacetyl tests

While opinion about the risks of diacetyl differ, the comments from vapers make it clear that everyone believes transparency is the way forwards. The only problem for vapers today is that only some companies offer this transparency. So how do you ensure you aren’t vaping diacetyl-containing juices?

The responses all revolve around the same key point, as Michelle Harndon from Mt. Baker explains:

Michelle Harnden

“Only purchase from reputable sources, and don’t be afraid to ask the question. Check out the websites and public statements from the companies you are purchasing from. If you don’t find the answer you’re looking for, ask.” – Michelle Harnden (Mt. Baker Vapor)

This advice was echoed by everyone we spoke to:

Grimm Green

“When in doubt ask the manufacturer for lab reports. If they don’t supply them, don’t shop with them. Plain and simple. I run a liquid company and get asked on a daily basis if our liquids contain any diacetyl. In my reply I always freely offer up our lab reports to prove it. Manufactures should have nothing to hide from the eyes of the consumer.” – Nick “Grimm” Green (GrimmGreen / NamberJuice)

Morton Moe

“A lot of juice-makers test their juices and publish the results. If you don’t want diacetyl in your juice, just stick to those. There are a lot of really good ones to choose from anyway.” – Morten Moe (the Vaping Giraffe)

Overall, the best thing to do if you want to avoid diacetyl is to stick to reliable companies who believe in transparency. Mt. Baker Vapor, NamberJuice, E-Cigarette Direct’s Halo brand and Black Note are all examples of companies who do things right, and you can also use reliable third-party vendors like Vapor Shark, who provide full test results on all of the liquids they sell.

Conclusion: Don’t Lose Perspective, But Don’t be Blinded by It 

The issues surrounding diacetyl are complicated. The important thing to remember is that vaping is likely to be much safer than smoking, whether e-liquid contains diacetyl or not. It’s important not to lose perspective and be overly worried about vaping. But at the same time, the fact that “it’s better than smoking” shouldn’t blind you to the very real issue of what it is you’re inhaling. In short, it is better than smoking, but you should still remember that vaping diacetyl-containing juice probably represents a real risk, and it can’t be batted aside easily.

As consumers ourselves, we need to put pressure on the industry for transparency, and we need to be skeptical of claims they make unless they provide substantiating evidence.

Phil Busardo

Phil Busardo really hits the nail on the head in his post on the diacetyl issue:

“We have a long way to go before we get the answers everyone is looking for, but in the meantime it’s very important to understand that vaping is about harm reduction not harm elimination. Use these products at your own risk, but do your best to educate yourself on potential issues and concerns. And always remember that the safest way to vape is to not vape at all… But don’t smoke either!” Phil Busardo (Taste Your Juice)

We’d like to thank Nick, James, Russ, Michelle, Brian, Morten, Chris and Daniel for taking the time to answer our questions and making this post possible.

Also, be sure to read what researchers had to say on diacetyl here.

Shopping Cart
Scroll to Top
Skip to content