Diacetyl, Acetyl Propionyl And Acetoin In E-cigarettes


Recently, several e-liquids have been removed from sale due to having been found to contain high levels of Acetyl Propionyl (AP) or Diacetyl (DA). The complex issue surrounding these two substances has divided opinions in the vaping industry as experts are uncertain as to how dangerous these substances can be to vapers and their health.

Acetyl Propionyl and Acetoin

Acetoin and Acetyl Propionyl are two ingredients which came on the scene as substitutes for Diacetyl after the vaping industry became worried that it may cause health problems. However both Acetyl Propionyl and Acetoin have been found in recent research to also contain chemicals that may contain or be converted into Diacetyl. While they were once considered to be a safer alternative to DA, they are now thought to potentially be harmful, as they can irritate the lungs due to the similarity to Diacetyl in their chemical composition.


diacetylDA or Diacetyl is a type of food flavouring which is regularly encountered in everyday life, however it has also been linked with lung problems if it is inhaled. Although it exists in nature, producing a buttery taste in beverages and foods, and is known to be safe to drink or eat, when it is inhaled it is now known to cause medical issues. One of the main conditions that it can cause is Bronchiolitis Obliterans, sometimes known as Popcorn Lung Disease. This name came from the fact that initially it was found among workers from a popcorn factory, however workers in plants that manufacture this chemical have also been found to develop the condition which causes irreversible damage and scarring in the lungs which may require a lung transplant to correct. While the link is not actually definitive, there has been a lot of evidence which has come to light from animal and toxicological studies which suggest that DA should not be inhaled and therefore should not be intentionally added to e-liquids. Many popular e-liquids have been shown to have higher levels than the safety limit which has been recommended by the OSHA.

Why are DA/AP in e-liquids?

One of the main reasons for adding DA and AP to e-liquids is because these substances produce a pleasant, buttery taste. Both AP and DA give fruit flavours a more ripe taste and enhance the pleasure of the vaping experience.

standard jacvapour e-liquidBack in 2010, it was realised that DA was present in many e-liquids and at that time, some manufacturers took steps to remove it from their products. Yet four years later, when some tests were performed on various e-liquids, it was found that these products still contained DA, even though the manufacturers were not aware that they contained any. This happened because the limit of detection for DA in e-liquids was actually set too high, at about 1% – well above the limit set by NIOSH. Further tests proved that around 74% of sweet flavoured e-liquids contained DA and AP, with almost half of these containing levels that were greater than the safety limit. Although the companies that failed the tests were informed of the problem, some have not yet rectified the situation.


As yet, vaping is still in an early development stage, and AP and DA are the chemicals which have drawn particular attention from the vaping community. However there has not yet been a foolproof study to demonstrate the effect that either of these chemicals may have on vapers’ health in the long term. Despite this, the evidence that has been revealed so far suggests that e-liquids should not contain either of these two chemicals for safety reasons since the research available has pointed to the fact that these substances can cause medical problems. It is therefore sensible to opt for an e-liquid that is 100% free of Acetoin, Acetyl Propionyl and Diacetyl in order to be sure of protecting your wellbeing when vaping.


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