What are Diacetyl, Acetyl Propionyl and Acetoin?
If you're concerned about diketones (diacetyl, Acetoin, and/or Acetyl Propionyl), you can try to avoid any "custard, creamy, rich, bakery" type flavors, and stay with tobaccos/fruits.
You can also deal with vendors who specifically list on their website whether diketones (diacetyl/acetyl propionyl) are used/possibly present.
1.
Ahlusion
2.
Mountain Oak Vapors has links to their lab reports in each juice description.
3.
The Vapor Bar has the lab reports on their blog.
4.
JuiceMafia has links to lab reports in some of their juice descriptions, and their report seems to cover a ton of their juices.
5.
NicoTicket also openly discloses which of their flavors contain diketones, which I appreciate because it allows us to make informed decisions about what to vape.
You could DIY and only use ingredients/vendors who verify ingredients or you could try vaping unflavored. Many members here choose to vape with no flavoring and enjoy it.
There are usually 4 different components in juice:
1. Propylene Glycol - the "flavor carrier" of e-liquid. A secondary source of "throat hit", but not as strong as the nicotine concentration. Some people have a sensitivity or even an allergy to PG. It's very thin.
2. Vegetable Glycerin - the "vapor maker" of e-liquid. Used as a sweeter in many food sources, and also as a skin emollient. It's very thick.
3. Flavoring
4. Nicotine
Purity of PG, VG and PEG - The Short Version