Nicotine Salt and Freebase E-Liquid: The Difference Explained
E-liquid sold in New Zealand contains nicotine in one of two forms: freebase nicotine, or a nicotine salt. This page explains the chemical difference and what it means in use. It is factual information about how the two forms behave; it is not a recommendation of either.
Freebase nicotine
Freebase nicotine is nicotine in its unprotonated form. In e-liquid it sits at a higher pH, which produces a more pronounced sensation in the throat as the concentration increases. That effect is what limits freebase e-liquid to lower concentrations in practice: above roughly 12 mg/mL most people find it harsh in a small device.
Nicotine salts
In a nicotine salt, the nicotine is combined with an acid — commonly benzoic acid. This lowers the pH of the solution, which reduces the throat sensation at a given nicotine concentration. That is what allows nicotine salt e-liquid to be used at higher concentrations than freebase.
Because the salt molecule includes the acid, it weighs more than the nicotine within it. A nicotine salt label can therefore state either the salt concentration or the nicotine concentration, and the two figures differ. Nicotine strength explained covers how to read the figures.
The legal limits in New Zealand
| E-liquid type | Maximum nicotine concentration |
|---|---|
| Freebase nicotine | 20 mg/mL |
| Nicotine salt | 28.5 mg/mL of nicotine (equivalent to 50 mg/mL of nicotine salt) |
These are different figures, and a product that states a nicotine concentration above the limit for its type is not compliant. A container of e-liquid sold at retail may also contain no more than 1,800 mg of nicotine in total, and must not exceed 120 mL unless it is nicotine-free.
Differences in use
| Freebase | Nicotine salt | |
|---|---|---|
| Throat sensation | More pronounced, increasing with strength | Less pronounced at the same nicotine concentration |
| Typical NZ strengths | 0 to 12 mg/mL | 10 to 28.5 mg/mL of nicotine |
| Device type | Mouth-to-lung at lower strengths; sub-ohm devices | Mouth-to-lung pod systems |
| Legal maximum | 20 mg/mL | 28.5 mg/mL of nicotine |
Device compatibility
Nicotine salt e-liquid is formulated for low-power, mouth-to-lung devices such as pod systems. Freebase e-liquid is used in mouth-to-lung devices at lower strengths and in higher-powered sub-ohm devices.
High-strength nicotine salt should not be used in a sub-ohm device. A sub-ohm device vaporises considerably more liquid per puff, so the nicotine dose per puff is much larger, which can cause nausea and dizziness.
Common questions
Is one form safer than the other?
Neither form is established as safer than the other. The difference is in the pH of the solution and the sensation it produces, not in the safety profile. Both deliver nicotine, which is addictive. Health questions should go to a GP or to Quitline on 0800 778 778.
Can the two be mixed?
Mixing produces an e-liquid with characteristics between the two. Where a strength or throat sensation is not right, changing to a different strength within the same type is the more predictable adjustment.
Why do some labels show two numbers?
Because a nicotine salt label may state both the salt concentration and the nicotine concentration. The nicotine figure is roughly 0.57 times the salt figure, so 50 mg/mL of nicotine salt is about 28.5 mg/mL of nicotine.
Related reading
Sources: Smokefree Environments and Regulated Products Regulations 2021, Schedule 5; Ministry of Health, Proposed regulation to clarify allowable nicotine concentration for some vaping products (June 2023).