Diacetyl in vape

Diacetyl is a chemical substance used to impart buttery flavor to food, but inhaling it is highly toxic to the lungs and can lead to a serious and irreversible lung disease known as "popcorn lung".

Although diacetyl is classified as "generally recognized as safe" (GRAS) by the US Food and Drug Administration (FDA) as a food additive, this safety determination is only for "consumption" and not applicable to "inhalation". When heated and inhaled through e-cigarettes, it causes significant harm to the lungs.

Key health risks: "Popcorn lung"
The most concerning health risk of diacetyl is that it can cause a rare and severe lung disease called bronchiolitis obliterans.

Name origin: This disease is commonly known as "popcorn lung", and it was first observed in a group of factory workers who had been inhaling diacetyl used for flavoring popcorn.

Pathological mechanism: Inhaled diacetyl damages the tiny airways (bronchioles) deep within the lungs, causing inflammation, scar tissue formation, and gradual blockage.

Serious consequences: This damage leads to airflow limitation, causing persistent coughing, shortness of breath, wheezing, chest pain, or chest tightness, and is irreversible. As the condition progresses, the lungs lose their elasticity and eventually may lead to respiratory failure.

Risk quantification: A risk assessment study shows that the Hazard Quotient (HQ) for non-carcinogenic risks from inhaling diacetyl by teenagers and adults due to using e-cigarettes is far above the safety threshold of 1, indicating a significant health risk.

Why is diacetyl present in e-cigarettes?
Manufacturers add diacetyl to some e-cigarette oils to create rich flavors similar to desserts, creams, buttery candies, cakes, or certain fruit flavors. A 2021 survey found that diacetyl and acetylpropionyl are still present in some e-cigarette oils.

Regulatory status: Global efforts are gradually strengthening restrictions
Due to the inhalation risk of diacetyl, major markets around the world have begun to take action:

USA: The FDA has officially included diacetyl in the list of "harmful and potentially harmful components" (HPHCs) in tobacco products. This means that e-cigarette manufacturers must report their content and prove that their products do not pose an inappropriate risk to public health when applying for product listing.

EU/UK: According to the Tobacco Products Directive (TPD), the release of diacetyl and acetylpropionyl in e-cigarette liquid must not exceed 22 μg/mL.

China: The national standard "Electronic Cigarettes" (GB 41700-2022) also clearly requires the detection and reporting of diacetyl in e-cigarette liquid and aerosol and reports the results.

How to reduce risks?
Preferred solution: The most effective method is to completely avoid using any e-cigarette products.

Pay attention to ingredients: If using, avoid choosing e-cigarette oils that indicate or imply flavors such as butter, cream, egg and milk, sweet treats, or candies, as these products are more likely to contain diacetyl.

Choose official products: Purchase products from official channels that meet local regulatory standards (such as the EU TPD standards), which have stricter limits on diacetyl content.

In conclusion, inhaling diacetyl poses clear and serious harm to the lungs, which is completely different from the safety of "consumption".