Researchers at Harvard T.H. Chan School of Public Health did a study on diacetyl and other flavoring chemicals in e-cigarettes and flavored liquids. Here's what they found:
They evaluated the presence of diacetyl, acetyl propionyl and acetoin in 51 cigarette-like products of different flavors. They found at least 1 of the chemicals in 92% of the samples, with 76% containing diacetyl. The authors recommend urgent action to evaluate the extent of diacetyl exposure from e-cigarettes.
The research team could have chosen to use a semi-regulated vaping wand or a box mod type with variable voltage or variable wattage features in vaporizing a variety of e-juice flavors they could have bought from a local vape shop. After all, real-world vapers have used different types of electronic cigarettes with schematics that range from a basic mechanical setup to a technically advanced system.
Yet, the researchers thought it prudent to test ordinary e-cigarettes or cig-a-likes because they're the most accessible to the public. Each e-cig comes with a standard cartridge of e-liquid that's available in several flavors. The team selected 51 flavored products for a quick sampling, but didn't identify the brands and flavors they chose.
The problem with the researchers' selection of "test subjects" is that the e-juice used by most over-the-counter e-cigarettes isn't as sophisticated as the ones sold by reputable brand-name manufacturers. The e-juice follows a typical recipe with three liquid bases and a combination of flavorings. And, it's often made from ingredients of dubious quality.
One thing this study has proven without a doubt is that many e-juice makers still make use of flavorings with diacetyl. On one hand, the researchers didn't assess the detected levels of diacetyl and other flavoring chemicals in each sample. Doctor Konstantinos Farsalinos pointed this out and added his expert opinion on this issue:
"… the assessments of the levels found in their samples… are quite low, much lower than what we found in our study. In many cases, the level of each compound is absolutely minimal, and it is NOT expected to raise any concerns about human health effects."
Although the study did what it set out to do by identifying the flavoring chemicals found in e-liquids used for vaping, it eventually failed to prove whether the amount of chemicals would ACTUALLY have a detrimental effect on one's health.
The media latched on to the fact that factory workers who were exposed to copious amounts of that chemical in the workplace went on to develop popcorn lung disease later in life. They didn't even consider that most of the flavorings used in making e-juice have absolutely minimal amounts of diacetyl and similar compounds that would normally be excreted by the body.