What are Nic Salts? Even if you have tried it, learn more.

what is nicotine salt

Whether you’re new to vaping or not – find out if nicotine salt e-liquid is for you.

Nicotine salt, sometimes abbreviated to ‘nic salt’, has been used in e-liquid for a few years now. It’s growing in popularity, yet those new to vaping, and even seasoned vapers who use it, might not know what it is. Or how it compares to the form of nicotine commonly found in e-liquids.

Without getting too technical and sounding like a chemistry professor, this article gives you some background on nicotine salt, how it differs from the traditional type, the pluses and minuses, and whether it’s right for you.

Back to nicotine basics.

Nicotine is the addictive substance found in cigarettes. It is also in most e-liquids to help replicate the sensation of smoking, although you can get zero nicotine e-liquids. Despite being addictive, it’s not been found to increase the risk of serious health problems.

The level of nicotine in UK e-liquids ranges from 0 to 20mg/ml. Users can select a level that they are comfortable with, which is often reflective of how much they used to smoke (if they did). The type of nicotine found in most e-liquids is called ‘freebase nicotine’.

What is freebase nicotine?

Freebase nicotine goes through a process to change its naturally occurring ‘salt’ state into a ‘base’ pure form. This increases potency, without increasing the dose. However, this also makes it more alkaline. It was developed back in the 1960s by a cigarette company.  

Are there any downsides to freebase nicotine?

Due to it being more alkaline, it is very harsh in high doses. For most vapers, the throat hit from a high-strength freebase nicotine e-liquid is too severe to enjoy. As a result, some of those new to vaping drop the nicotine level to make it more palatable, but then they miss the nicotine hit they are used to. So they return to cigarettes to satisfy their craving.

What are nic salts?

Well, it’s got nothing to do with the salt you put on your chips. Nicotine salt forms naturally in leaf tobacco. However, in this natural state, it doesn’t travel easily to the nicotine receptors in our body (like the altered more potent ‘freebase nicotine’ does).

If pure nic salt is added straight to e-liquid, it would have to be vaped at an extremely high temperature for the nicotine to be effective. And even then, it wouldn’t do the same job as freebase nicotine.

So, the clever guys in white coats worked out, by increasing the acidity of nicotine salt, our bodies can absorb it more rapidly and it can vaporise at lower temperatures.   

The pluses and minuses of nicotine salt e-liquids?

Due to nicotine salt being less alkaline, you get a much smoother throat hit compared to freebase nicotine. It’s also absorbed into the bloodstream faster. Meaning you can use a higher concentration of nicotine to satisfy your craving, without the harshness.

But before you click the ‘buy now’ button or rush out to your local vape shop, there are a few other things to consider. Nic salt e-liquids can’t handle high flavour complexity or generate large clouds compared to freebase nicotine e-liquids.

Are nic salt e-liquids right for me?

As mentioned above, there are advantages and disadvantages to using them. It just depends on the style of vaping you prefer and where you are on your vaping journey. For example, if you are new to vaping and looking to quit smoking, then nicotine salt e-liquids could be for you. They’ll help relieve your nicotine craving but without a harsh hit.

Another thing to consider is the type of vape you use or are considering using. Nicotine salt e-liquids are better suited to pod devices like our DOT Pro and lower power vape devices. High powered vapes and sub-ohm devices should be avoided as nic salt e-liquids are usually 20mg and above, potentially delivering too much nicotine. You can use nicotine in regular vaping devices if you keep the power lower.

Hopefully, this article will go some of the way to answering the question ‘what are nic salts?’. If you would like more advice on nicotine salt, please get in touch with one of our advisers who will be more than happy to help you.

For information about choosing the right nicotine strength for you when vaping, read our article How much nicotine in a vape?

E-liquid Testing Results


Recent developments in the understanding of e-liquid safety and the effect of some of the flavour components have led to increased scrutiny across the industry with regards three key compounds. While these three compounds are used safely in food, special consideration must be given to inhalation use because the lungs are not equipped with the same level of defence mechanisms compared to the stomach i.e. when something is swallowed. This blog discusses these compounds of interest, why they need to be monitored and how Liberty Flights is ensuring the quality and safety of our e-liquids.

What is Diacetyl (DA)?

Diacetyl (or butane-2,3-dione) is an organic compound with the structure shown below:


It is classified as an alpha diketone (two C=O groups, side-by-side, ringed in red) and has an intense, buttery flavour. This means that it is often added to food as a flavouring agent but it can also occur naturally in alcoholic beverages.


What is Acetyl Propionyl (AP)?

Acetyl propionyl (or 2,3-pentanedione) is another alpha diketone with the structure illustrated below:


AP also has a buttery taste and can be found in food flavourings.


What is Acetoin?

Acetoin (or 3-hydroxybutanone), is a ketone (ringed in red), not a diketone like DA and AP, and has the structure shown below:


Acetoin is described as having a pleasant buttery odour, making it a popular food flavouring. It is also a chemical intermediate in the production of DA.


Why shouldn’t they be present in e-liquids?

During the use of DA as a flavouring for butter popcorn in the US, it was discovered that workers exposed to the flavouring during manufacture were at risk of Bronchiolitis obliterans (BO). BO is a rare and life-threatening form of non-reversible obstructive lung disease in which the bronchioles (small airway branches) are compressed and narrowed by fibrosis (scar tissue) and/or inflammation. After investigation, it was concluded that DA contributed to the damage caused and there is good data to support the presumption that both DA and AP are dangerous if inhaled (see links below). Evidence suggests the respiratory damage is linked specifically to the functional group of these molecules (an alpha diketone).

(1)    http://www.cdc.gov/niosh/updates/upd-08-15-11.html

(2)    http://tpx.sagepub.com/content/36/2/330.short

(3)    http://tpx.sagepub.com/content/40/3/448.short

What is most concerning is that the maximum exposure limits for DA and AP are very low and it is vital that these compounds are tested for, at the lowest possible level, in any inhalation product. The recommended exposure limit (REL) for DA is 5 parts per billion (ppb) as an eight-hour, time-weighted average, (TWA) during a 40-hour work week. For AP the REL is 9.3 ppb(1).

This data has been applied to e-liquids by registered toxicologists (BIBRA Toxicology and Consulting) contracted by ECITA (Electronic Cigarette Industry Trade Association), who have set limits for DA and AP to 20 µg/ml in e-liquids, based on a daily consumption of no more than 3 ml of e-liquid per day. The possible inclusion of DA and AP, at any level, in some sweet tasting e-liquids is therefore a concern to the industry in general. According to the British Standards Institution (BSI) PAS 54115:2015 (Vaping products, including electronic cigarettes, e-liquids, e-shisha and directly-related products – Manufacture, importation, testing and labelling guide) these compounds are not permitted in the production of e-liquids.

Although not a diketone, there is conflicting evidence about the effect of acetoin on the body when inhaled. What is known is that it is a respiratory irritant and combined with the fact that it is an intermediate in the formation of DA, it has become a compound of concern. Bibra have quoted a safe level of 8400 µg/ml and Liberty Flights Ltd has chosen to test for and monitor acetoin levels as more data continues to become available.

Liberty Flights has taken the step of having our e-liquids tested at an independent, GMP laboratory to confirm that the level, if any, of DA, AP and acetoin are within acceptable, safe limits for inhalation.

How and where is the testing performed?

In order to get the highest quality, reputable data, Liberty Flights approached a well-known independent, GMP (Good Manufacturing Practice) laboratory and undertook extensive method development to create a method which had the highest possible level of sensitivity, despite the often complex mix of flavourings.

It was important to Liberty Flights to use an accredited laboratory that would perform the testing to the highest standard so selecting one with GMP approval was vital. GMP outlines the standard required in order to conform to legislation covering pharmaceutical manufacture and testing. As a result, standards are very high and ensure reputable, repeatable data is obtained.

Using an independent laboratory was also important to Liberty Flights, as we wanted the results to be unbiased, giving our customers confidence that the results were verified independently without interference from anyone invested in the outcome.

The method for detecting and quantifying DA, AP and acetoin uses High Performance Liquid Chromatography (HPLC). This approach separates compounds of interest from each other in the e-liquid. In HPLC, the sample is passed through a column (usually containing silica based packing), with a flowing solvent mixture through the system. Based on their structure, the individual components in the e-liquid sample have unique affinities for the packing material (i.e. silica) and the solvent mixture, and retain on the column for different periods of time relative to that affinity, before being eluted. This allows the different components to be detected as discreet peaks at different times by the detector.


Example of a HPLC chromatogram


The concentration can then be calculated based on the intensity of the response to that compound in the detector (area under peak). This is a widely used analytical technique and the method development carried out by the laboratory ensured the limit of detection (LOD) and limit of quantification (LOQ) for the method was as low as possible whilst maintaining precision and specificity.

XO e-liquid test results


The certificates for the first 27 liquids tested can be found where you see the certificate symbol next to any flavour on the product pages. Due to the number of liquids available, this process is ongoing and as more results become available they will be published on the relevant product pages of our website.


For reference, 1 µg/ml equals 1 ppm and therefore, the safe limit of 20 µg/ml referenced previously equals 20 ppm for DA and AP and 8400 µg/ml equals 8400 ppm for Acetoin.

The limits of detection for the methods used to conduct this testing are 2 ppm. It can therefore be said that any e-liquids showing a result of ‘none detected’ (ND) have levels below 2 ppm and are therefore well within safe limits.

Liberty Flights is pleased that the results reflect the thorough approach taken to e-liquid quality.

Guest liquids

At Liberty Flights all of our guest e-liquid manufacturers are required to supply the appropriate certification on DA, AP and acetoin levels to ensure we only sell the best quality products. Please contact the manufacturer directly for more information.

A Final Note

Liberty Flights will continue to invest resources into scientific development to ensure that we produce e-liquid that is of the highest quality and is as safe as it can possibly be. If you have any questions about this blog, or anything else about Liberty Flights products, please feel free to get in touch via our customer service team or leave your comments below and we will do our very best to get back to you as soon as possible.


Lucy Robins

Chief Scientific Officer