Updated and editorially reviewed by VapePoint: August 2, 2026. General information only; not personal medical advice.
Diacetyl is a flavoring and aroma substance used in various industrial applications. It became widely known after high and prolonged occupational exposures were linked to a rare and severe obstructive lung disease, bronchiolitis obliterans.
What is the connection to vaping liquids?
Tests have detected diacetyl or related substances in some vaping liquids and aerosols; the sources here do not establish their prevalence in products sold today. Composition varies between products, batches and conditions of use, and exposure cannot be inferred from the label or flavour alone. Manufacturer and importer details and test records help trace a product’s origin and the tests performed; a shop’s or brand’s reputation is not a measurement of diacetyl exposure.
What cannot be determined?
The disease described in factory workers does not prove that a particular vaping product will cause the same disease, but it also does not justify saying that inhalation exposure is unimportant. Currently, there is insufficient evidence to accurately quantify the risk for every user, every liquid, or every level of exposure.
The fact that a flavoring is approved for use in food does not automatically make it suitable for inhalation. A test record describes the substances tested and the results under those test conditions; it does not by itself establish the level of risk during actual use.
Making an informed choice
For adults who smoke, completely switching from cigarettes can reduce exposure to many substances in smoke. For people who do not smoke, or those with respiratory symptoms, starting to vape is not a medical solution. If you experience shortness of breath, chest pain, or a persistent cough, stop using the product and seek medical evaluation.