This information came from this blog here:
Sweetening and additives | E-Cigarette Forum
And was originally posted by @ol'docporter before he left the forum.
But I wanted to take the relevant parts of that blog and repost it so it's in a place I won't lose. Therefore I'm making my first blog post.
Acetyl Pyrazine- Sold by TPA. Used in cigarettes and cookies to impart a "toasty" taste.
At 0.5% it gives your juice a baked, toasted, or crispy note
At 1%, it adds the taste of toasted mixed nuts.
At 2% it adds a taste similar to Fritos corn chips.
Caffeine- Sold by FW. The active ingredient in coffee. Does almost nothing for your juice. According to my brother (who has Ph. D.s. in both pharmacology and toxicology), you would have to sub-ohm over an ounce of 10% caffeine juice at about 70w to get the effect of 1 cup of coffee. Pretty much useless.
To anyone who says they get a buzz from vaping caffeine, I'd like to borrow you for a stage hypnosis act!
Capsicum - Sold by FW. The chemical that makes hot peppers hot; also used as an analgesic. used in VERY SMALL amounts in your juice, it can cure sore throat. A little more and you've got yourself an ejuice akin to hot pepper joke gum. More than that, and you may win a one-way ticket to the emergency room. This stuff can be dangerous.
Keep in mind that the capsicum sold by FW is 375 times the strength of the hottest pepper known to man.
Ester of Wood Rosin- Sold by FA as bitter wizard, also a main ingredient of MTS vape wizard by FA. Used in Gatorade and some colas to give a bitter note. At 0.5%, masks the flavor of vg and pg, thus only leaving the taste of your flavor mix. At 1% or higher, gives the pleasant bitter ring of colas, whiskeys, or dark chocolate.
Ethylguaiacol- Sold by SV and is a main ingredient of dnb drops wg by INW. Adds a smoky, ashy note to your juice. Great for making cigar, cigarette, and pipe flavors more realistic. This stuff requires a long steep in order to taste it, at least 2 weeks.
Ethyl Maltol- Sold by TPA. Besides sugar, this is the other major ingredient in cotton candy (floss), which gives it its characteristic flavor. It is commonly used as a sweetener in ejuice. Its physical properties cause it to gunk up coils slightly.
Gamma Octalactone- Sold by TPA and SV. This is the stuff they put in fudgesicles and other non-dairy treats to make them taste creamy. At 50ppm, it will make any juice you make extra creamy; you'd swear there's real cream in it!
WARNINGS: Any more than 50ppm tastes atrocious. Tpa sells it full strength, so you will need to dilute it to 1% in pg before using; then you can measure it to 0.5% of your mix.
Guaiacol- Sold by TPA, and is a main ingredient of both black fire by FA and dnb drops wg by INW. This is the chemical that gives smoked meat and fish their smoky flavor. As you can imagine, it makes anything you mix it with taste smoked, but not burned. It also adds throat hit. It must be steeped for at least 2 weeks to reach its full potential.
Isobutavan- Sold by TPA, and is a main ingredient of MTS vape wizard by FA, smooth by TPA, and flavor toner/enhancer by FW. This is the "thickening" agent in the aforementioned enhancers. It does not actually thicken your juice any, but alters the mouth feel of the vapor to seem thicker. It also cancels the vapor thinning effect of some flavorings, thus making your clouds appear denser. Too much of it makes everything taste like vanilla.
Malic Acid- Sold as sour by TPA. This is the sour note in old fashioned sour balls candy as well as salt and vinegar crisps. I'm sure you get where this is going regarding ejuice. It tends to form crystals on coils.
WARNINGS: Like any acid, this stuff eats kanthal, albeit slowly, and when used with nickel coils, produces nickel compounds classified as class "A" carcinogens (sorry tc fans, and no, I'm not showing any documentation, as it is simple chemistry: nickel+acid+air=horrible, dangerous stuff; read a ....ing textbook).
4-Methyl Guaiacol- Sold by TPA and is a main ingredient of black fire by FA. Added to foods to make them taste as if they have been cooked on a grill or over a campfire. Gives your juice a wood, charcoal, or coal fire note. Just a touch can make your toasted marshmallow vape really take you back to camping with the folks.
Methyl Menthyl Acetate- Sold as koolada by TPA and kool effects by FW. Menthol cool without menthol taste. That simple. Of course, you can make your own by simply dissolving menthol crystals into pg and cooking it at 180F until it no longer smells like menthol. It takes a long time, much patience, and careful heating; this is how I do it, but then, I'm an alchemist.
Piperine- Sold as flash by FA. This is what gives black pepper its spiciness Can be used to add throat hit or mixed in equal measure with FA pepper black to add the taste of fresh cracked pepper to your savory mixes.
Sucralose- Sold by TPA. Artificial sweetener that is ubiquitous, you know, everywhere and in everything; it's "splenda, the artificial sweetener made from real sugar!" Well, being made from sugar, you can imagine what it does to coils, not to mention that a dry hit of this will give you more "tar" than the analogues you're likely trying to avoid.
Syringol- Sold in pure crystal form by TPA (for a limited time only) and is a main ingredient in both black fire by FA and dnb drops wg by INW. This is the chemical that gives smoked meat and fish their smoky aroma. It is the main flavor in all commercial smoke flavorings, and was even added to Gen. Patch action figures in the 80s to give them the "smell of battle". Mix crystals 13.5% in pg to make extract. Be careful not to overdo it with this flavor, or your juice will taste like phenol (that nasty background note in sore throat spray).
Triacetin- Sold as aaa magic mask by FA, and is a main ingredient of mts vape wizard by FA, smooth by TPA, and flavor toner/enhancer by FW. This stuff is used in many processed foods and in cigarette filters to smooth out harsh notes. It does this by temporarily numbing certain taste receptors in your tongue. This is the reason you can stomach breakfast cereals, microwave meals, and all the added paper and other trash they put in commercial cigarettes. Likewise, it can make some ejuices tolerable, maybe even tasty, that without it would be abominable. This stuff is actually amazing. If you really suck at diy, and your juice tastes like an abortion, you need this stuff; it can save even some of the worst tasting mixes.
SIDENOTE: Triacetin is also the most amazing coil cleaner! It actually does for cotton what conditioner does for hair; vg slowly clogs wicks, and pg makes the fibers brittle, but aaa unclogs wicks and plasticizes fibers, leaving them flexible once more.
Triethyl Citrate- Sold by TPA. This is an emulsifier used to make essential oils water soluable. It is used by FA, TPA, INW, FW, CAP, HS, and just about every flavor company everywhere. It is used in most popular flavors. This is the "secret ingredient" that turns oil soluables into water soluables, if you know how to use it. think of it as "the flavorer's stone", sought after to turn crap flavors into gold.
Trimethyl Pyrazine- Sold by TPA. nearly identical to acetyl pyrazine at top of list.
Separate names with a comma.