Nicotine Salt vs. Freebase Nicotine
When using a vape or e-cig, users are exposed to either liquid “Nicotine Salt” or "freebase" nicotine. Although both are forms of nicotine, they interact with the body very differently. First came Freebase Nicotine in the 60’s when cigarette companies laced tobacco with salt-like diammonium phosphate to release ammonium (ammonia) when the cigarette combusts changing natural nicotine to base form. Nicotine Salts use Benzoic Acids to manipulate the chemical structure and bioavailability.
The name "freebase" has no relation to the way it is ingested, rather the modification of the nicotine with acids. Examples of this have been found in the modification of Cocaine to Freebase Cocaine using baking soda. Freebase Nicotine is a modified form of naturally occurring nicotine, resulting in a liquid with a more basic (higher) pH level of around 8.
Freebase nicotine was the standard for vape liquid since the inception of the e-cigarette and usually contains lower levels of nicotine at 3mg/ml to 12mg/ml. Usually, most free base liquids are on the lower level of the spectrum in nicotine concentration and rarely go past 12mg/ml because the physiological and psychological effects would be too intense and may have adverse effects on the user. In order to compete with combustion, modern vape companies needed to find a product which could deliver the same intense rush of nicotine provided by a cigarette, without allowing the user to feel the negative effects on the throat, lungs, or respiratory system.
Just like "freebase" nicotine, "salt" is also more of a misnomer than anything. The process does not turn the nicotine into a salt like material. Instead, this term comes from purely the scientific definition - "a base that has been mixed with acid".
Large vape companies protonated nicotine salts with a chemical called benzoic acid to create a form of nicotine which is absorbed into the bloodstream more effectively and less painful to ingest. This means people can buy and vape much more of the addictive stimulant drug without feeling the negative physical effects, such as burning in the throat or chest. It also means the nicotine is felt much quicker and in higher intensity than freebase nicotine, just like a real cigarette.
Reduced pain in addition to predatory marketing strategies aimed at children and young adults is why companies selling nicotine salt based products became so popular, so quickly and continue to dominate the market today.
The differences between nicotine salt and freebase nicotine may also demonstrate why people have mixed results when switching to vapes to quit smoking.