Yes, some e-liquids on the market contain diacetyl. We need to keep in mind that tobacco cigarettes contain 301-433 ppm of diacetyl, 100 times more than when it is present in e-cigarettes. This doesn’t stop the issue being blown out of proportion.
Updated: 19th March 2020
Let’s look in more detail at diacetyl and how it got its reputation in the vaping market.
What is Diacetyl?
How is potential exposure related to harm, and the lung disease commonly known as popcorn lung?
Vapers have picked up bits and pieces of information from the e-cigarette forums or via a Google search, but they still remain confused as to whether this should be a major concern for a vaper? It’s an understandable conundrum as there is a lot of conflicting information online. Let’s have a look at some facts about diacetyl and its potential to cause harm to a vaper.
The Science Bit – Diacetyl (aka 2,3-butanedione)
Firstly, let’s discuss the chemistry. Diacetyl (aka 2,3-butanedione) is an important flavour compound found in dairy products, wines, and beers. In wine, diacetyl has a buttery aroma and adds complexity to the sensory impact of the wine. It is a prominent volatile (easy to evaporate) constituent of buttery flavourings and is used extensively in the flavourings industry. We eat foods every day that contain diacetyl as a flavouring additive/natural ingredient and it is generally recognised as safe.
So you might ask yourself what all the fuss is about!? Well, the safety of diacetyl as a food additive has been established through years of studies conducted by scientists. However; the average person would only have exposure to trace amounts (if any) of vapourised diacetyl through the food that they eat. Back in 2002, Occupational health scientists in the USA conducted studies at six microwave popcorn plants to determine if diacetyl exposure had contributed to unusually high cases of severe obstructive lung disease amongst the factory workers. Symptomatic workers had developed an irreversible type of lung damage called constrictive bronchiolitis.
Working as a mixer of buttery flavourings and heated soybean oil was associated with higher exposure to diacetyl vapour than working in other areas of the plant. People who had worked as mixers for more than 12 months were more likely to develop respiratory symptoms. The term ‘popcorn lung’ described this airway damage. Subsequent acute and subchronic toxicology studies have shown that vapour from heated butter flavourings can cause damage to the airways in animals. Overall, the body of evidence points to diacetyl as one agent that can cause flavourings-related lung disease.
What about using Acetyl Propionyl instead?
While conducting your own research into diacetyl, you might have come across another chemical called acetyl propionyl (aka 2,3 pentanedione). When the inhalation safety concerns of diacetyl established itself, the flavourings industry developed a substitute called acetyl propionyl that gave the same buttery flavour profile.
Its chemical structure is very similar to diacetyl since acetyl propionyl is a 5-carbon alpha-diketone and diacetyl is a 4-carbon alpha-diketone. So the flavourings industry solved the problem? Not really, no. Recent studies document that inhalation exposure to acetyl propionyl causes airway epithelial damage that is similar to diacetyl in laboratory studies.
Diacetyl and e-cigarettes
This sounds terrible, I can hear you saying! Let’s bring the discussion back to the context of e-cigarettes. As you all know, there are a vast array of flavoured e-liquids on the market for you to pick from. In the last few years, sweet dessert type flavours have grown increasingly popular and a minority of e-liquid manufacturers have used butter type flavourings that we would deem unsuitable for inhalation. This has been documented in the press and several scientific journals.
But we must consider a principal of toxicology that the level of exposure matters and ‘the dose makes the poison’. The popcorn plant workers and laboratory animals experienced far higher levels of vapourised diacetyl than you would expect an e-cigarette aerosol to contain, even if the e-liquid in question contained it as a minor ingredient component. Indeed, tobacco cigarette smoke contains 301-433 ppm of diacetyl per cigarette. This level is far higher than any previously reported in e-cigarette aerosols. So we must bear this in mind when we evaluate the risk posed by diacetyl.
Does e-liquid have to contain Diacetyl?
So what conclusion can we draw from this evidence? We believe that you have already made the life-changing decision to quit smoking and we have a duty of care to you, our valued customers. Diacetyl and acetyl propionyl do not need to be present, even at low levels, for you to enjoy your favourite flavour. Delicious buttery/dessert type flavours are possible diacetyl and acetyl propionyl free, we know this through work we have undertaken with our flavour suppliers and extensive analytical testing. At this time, the long-term risk to vapers from diacetyl containing e-liquid is unknown. The risk is relative, and we all take risks in our everyday lives. But why take an unnecessary risk?
What is the Totally Wicked ‘Guarantee Of E-liquid Excellence’?
With an ever-expanding e-liquid industry and an ever-expanding body of knowledge regarding e-liquids, it is vitally important to understand exactly what you are buying.
To this end, we offer a guarantee of e-liquid excellence for our customers. This is a promise to always do more than is expected. To provide understanding of how we manufacture our e-liquids and the safeguards in place.
Our e-liquids are independently tested at SkyLab-Med Laboratories in Athens. The tests ran under a regime specified by Dr Konstantinos Farsalinos, one of the world’s most eminent e-cigarette researchers. We believe we are the only e-liquid manufacturer and supplier that has undertaken such a test and validation regime under the direction and facility support of such a leading academic. Using GC-MS and GC-FID techniques for assurance that the processes and procedures are fit for purpose. Also to assure the quality and safety of our end consumer products.
Click to view Totally Wicked’s ‘Guarantee of e-liquid excellence’ page.