How Nic Salts are Made | Nicotine Salt Manufacturing

Quick Guide on How Nic Salts are made

• Purified nicotine is sourced from tobacco or made synthetically.
• A suitable organic acid is selected, such as benzoic, lactic or malic acid.
• The nicotine and acid are measured using a controlled molar ratio.
• They are mixed together, which protonates the nicotine and forms a nicotine salt.
• The mixture is blended with PG and VG to create the e-liquid base.
• Flavourings and any permitted additives are added.
• The batch is thoroughly mixed to make sure the ingredients are evenly distributed.
• The finished liquid is tested for nicotine strength, purity, consistency and stability.
• It is then filtered, filled and packaged into bottles, pods or cartridges.

What are nic salts? Explained scientifically

It’s important to first explain the science behind what nic salts actually are. This will help us better understand why certain methods are used in their production.

The use of the word ‘salt’ can sound as though nicotine salts are granular crystals resembling table salt. That is obviously not the case, since nic salts must come in liquid form to be vaped, so why salt?

In chemistry, a salt is a compound made from positively and negatively charged ions. Nicotine acts as a base, meaning it can accept a proton from an acid. Once that happens, it becomes positively charged and is paired with the negatively charged remainder of the acid.

The simplified reaction looks like this:

Nicotine + acid ⇌ protonated nicotine⁺ + acid counterion⁻

Nicotine that has not accepted a proton is usually called freebase nicotine. Once protonated, it becomes part of a nicotine salt system.

Most commercial liquids are not necessarily made up of one single form. The finished product may contain a combination of:

• Freebase nicotine
• Monoprotonated nicotine
• Excess unreacted acid
• Acid counterions
• PG, VG and flavouring compounds

The balance between these components depends on the acid, the amount used and the composition of the surrounding liquid. Research into the different chemical forms of nicotine explains how nicotine can move between freebase and protonated states rather than remaining permanently fixed in one form.

Step 1: Producing purified nicotine

Before nicotine can be converted into a salt, manufacturers need a highly purified source of nicotine.

There are two main options:

• Tobacco-derived nicotine
• Synthetic nicotine

Nicotine occurs naturally in tobacco plants. It can be extracted from leaves, stems, roots and other nicotine-containing plant material before being separated from unwanted plant compounds.

The crude material may contain:

• Other tobacco alkaloids
• Plant oils and pigments
• Sugars
• Nicotine oxidation products
• Tobacco-specific nitrosamines
• Residual processing chemicals

For that reason, crude tobacco extract is not simply added to an e-liquid. It first goes through purification and analytical testing.

Extraction methods vary. One documented approach uses supercritical carbon dioxide to extract and purify nicotine from tobacco material. Other processes may use solvent extraction, acid–base separation and further purification stages.

The important distinction is this: nicotine extraction and nicotine salt formation are separate processes.

Nicotine is extracted and purified first. It is then combined with an acid later.

Synthetic nicotine

Nicotine can also be produced without extracting it from a tobacco plant. This material is generally described as synthetic or non-tobacco-derived nicotine.

The final nicotine molecule may be chemically equivalent to tobacco-derived nicotine, but the raw-material profile can differ. Nicotine has two mirror-image forms, known as enantiomers:

• (S)-nicotine
• (R)-nicotine

Tobacco naturally contains overwhelmingly (S)-nicotine. Some synthetic production routes can initially produce a mixture of both forms, although further processing can create highly enriched (S)-nicotine.

Synthetic nicotine should not automatically be assumed to be purer simply because it is not extracted from tobacco. A 2024 study comparing synthetic and tobacco-extracted nicotine samples found differences in impurity profiles between the tested materials. Each supply still requires proper verification.

Manufacturers may test nicotine raw materials for:

• Nicotine concentration
• Enantiomeric composition
• Related tobacco alkaloids
• Nicotine degradation products
• Tobacco-specific nitrosamines
• Residual solvents
• Water content
• Heavy metals

Only after the starting nicotine has met the manufacturer’s specification does the salt-forming stage begin.

Step 2: Choosing an acid

Nicotine salts can be created using several different acids. Benzoic acid is widely associated with nic salt e-liquid, but it is far from the only option.

A study analysing 23 commercial refill liquids identified at least six different acids. Benzoic, lactic and levulinic acids were among the most frequently detected.

Acids identified in commercial or experimental nicotine formulations include:

Not all of these acids are used equally often. Some have been found in commercial products, while others appear in patents, research formulations or specialist applications.

What determines which acid is used?

Manufacturers need to consider more than whether an acid is capable of protonating nicotine.

Selection may be influenced by:

• Acid strength
• Molecular weight
• Solubility in the carrier liquid
• Required acid-to-nicotine ratio
• Flavour and odour
• Formulation stability
• Compatibility with PG and VG
• Behaviour when heated
• Potential aerosol emissions
• Interaction with coil and device materials

Another study found that acid choice could affect the transfer of certain metals from device components into the aerosol.

In that research, lactic-acid formulations behaved differently from benzoic- and levulinic-acid formulations.

This is an important factor for e-liquid manufacturers to consider since it dictates how many impurities from parts like the coil leach into what’s inhaled. This can have a dramatic impact on safety and flavour too.

This is why an acid being suitable for food does not, by itself, establish that it is suitable for an inhaled product.

Step 3: Calculating the nicotine-to-acid ratio

The nicotine and acid need to be measured according to the intended chemical ratio.

That ratio is normally calculated in moles, not by using equal weights.

A mole represents a fixed number of molecules. Because nicotine and each acid have different molecular weights, one gram of nicotine does not contain the same number of molecules as one gram of benzoic acid.

For a simple monoprotonated salt made with a monoprotic acid, an equimolar formulation would use:

• One mole of nicotine
• One mole of acid

This is described as a 1:1 molar ratio.

Equal weights would not create the same ratio.

Does every nic salt use a 1:1 ratio?

No. Commercial products can contain more or less acid than would be required for a strictly equimolar mixture.

Analysis of commercial liquids has found considerable variation in acid-to-nicotine ratios. Some products contain less than one mole of acid per mole of nicotine, while others contain several times more acid than nicotine.

The result may be:

• Less acid: a larger freebase nicotine fraction may remain
• Around 1:1: extensive monoprotonation may occur
• Excess acid: some acid may remain unreacted in the liquid
• Polyprotic acid: a more complicated mixture of ionic forms may develop

The actual result also depends on the solvent system and other ingredients. Simply knowing how much acid was added does not always reveal exactly how much nicotine is protonated.

Step 4: Combining the nicotine and acid

Once the quantities have been calculated, the nicotine and acid are brought together under controlled mixing conditions.

The precise order varies.

A manufacturer might:

• Dissolve the acid in part of the PG (propylene glycol)
• Add the acid directly to purified nicotine
• Prepare an acid solution before adding nicotine
• Use a pre-manufactured nicotine salt concentrate
• Add both ingredients separately to the e-liquid carrier

Some acids are liquids, while others are crystalline solids. A solid acid may need to be dissolved before it can be evenly distributed throughout the formulation.

Agitation helps the components mix. Gentle, controlled heating may also be used where an acid is difficult to dissolve, although unnecessary heat exposure can contribute to nicotine and flavour degradation.

Published patent examples show nicotine being combined with acids such as benzoic, malic, citric, levulinic, salicylic, succinic and pyruvic acid. Some examples use ambient mixing; others describe heat being applied until a homogeneous formulation is produced.

What happens during mixing?

As the nicotine and acid come into contact, proton transfer occurs.

The acid donates a proton to nicotine. Nicotine becomes positively charged, while the remaining part of the acid carries a negative charge.

The two ions are associated within the surrounding liquid, creating the nicotine salt system.

This does not turn nicotine into an entirely different drug. It changes the molecule’s charge state and how it behaves within the formulation.

Step 5: Blending the nic salt into the e-liquid base

After the nicotine and acid have been combined, the mixture is incorporated into the rest of the e-liquid.

The base normally contains:

• Propylene glycol
• Vegetable glycerine
• Flavourings
• A controlled amount of water in some formulations
• Other permitted formulation ingredients where applicable

Propylene glycol

Propylene glycol, usually shortened to PG, is a comparatively thin liquid. It is used as a carrier for nicotine and flavouring compounds and can help a liquid move through smaller wicking channels.

Vegetable glycerine

Vegetable glycerine, or VG, is more viscous. It contributes to the density and volume of the aerosol but can make a liquid slower to wick if used at a high proportion.

Flavourings

Flavouring concentrates are blended into the carrier at carefully controlled quantities. Their suitability has to be considered in the context of inhalation and heating, not merely their use in food.

Under current MHRA guidance, a notifier should provide available toxicological information on ingredients in both their heated and unheated forms, along with information on associated emissions.

Is a dry nicotine salt made first?

Not necessarily.

The name can give the impression that manufacturers first produce a dry nicotine salt crystal and then dissolve it into an e-liquid. That is one technically possible route, but it is not the only way to make a nic salt formulation.

There are two broad approaches.

Pre-manufactured salt or concentrate

A nicotine salt may be produced or purchased as a concentrated intermediate. The required quantity is then added to the main e-liquid mixture.

This can make handling, storage and dosing more consistent, depending on the salt and the supplier.

In-situ salt formation

Freebase nicotine and an acid can be added separately to the carrier liquid. Protonation then takes place within the formulation itself.

Commercial product-notification research has identified both explicitly named nicotine salts and products listing nicotine alongside a separate organic acid. This supports the conclusion that different formulation routes are used.

In either case, the finished liquid remains a chemical equilibrium. Dilution into PG, VG, water and flavouring compounds can influence the proportion of nicotine present in each form.

Step 6: Homogenising the finished batch

Once every ingredient has been added, the batch must be mixed thoroughly.

Poor mixing could leave different parts of the same production run with different concentrations of:

• Nicotine
• Acid
• Flavouring
• PG
• VG
• Water

Commercial manufacturers may use closed mixing vessels, overhead agitators, recirculating systems or in-line mixing equipment. The appropriate method depends on the batch size and the viscosity of the liquid.

The objective is straightforward: every filled bottle or pod should contain the same formulation.

Controlling air, heat and light

Nicotine can oxidise when exposed to oxygen, heat and light. Oxidation may lead to gradual changes in:

• Colour
• Odour
• Flavour
• Nicotine-related impurities
• Overall product stability

Manufacturers may reduce exposure by limiting mixing time, using closed equipment and selecting packaging that protects the liquid during its stated shelf life.

Some processes may also include filtration or deaeration before filling. These are not universal requirements, and the exact method depends on the manufacturer’s validated production process.

Step 7: Testing the finished nic salt e-liquid

Making the liquid is only part of the process. The finished batch needs to be checked against its specification.

A quality-control programme may include the following areas.

Nicotine concentration

Testing confirms that the actual nicotine level matches the intended strength and remains within the permitted tolerance.

Acid concentration

The type and amount of acid can be verified to ensure that the correct nicotine salt formulation was produced.

Nicotine protonation

Manufacturers and researchers can measure the proportion of nicotine present in freebase and protonated forms.

This is more complicated than taking an ordinary pH reading. PG and VG form a largely non-aqueous mixture, while conventional pH measurements are primarily designed for water-based solutions. Diluting an e-liquid with water can change the very chemical balance being measured.

Researchers have developed several techniques to examine nicotine form, including titration, extraction methods and nuclear magnetic resonance spectroscopy. A 2024 study demonstrated the use of benchtop NMR to measure nicotine protonation directly in e-liquids.

Nicotine impurities

Testing may look for nicotine-related compounds such as:

• Nornicotine
• Anatabine
• Anabasine
• Cotinine
• Myosmine
• Nicotine-N-oxide
• Other degradation products

The expected impurity profile may differ between tobacco-derived and synthetic nicotine.

Tobacco-specific nitrosamines

Tobacco-derived nicotine can be assessed for tobacco-specific nitrosamines at suitably low detection limits.

Synthetic nicotine does not come from tobacco, but that does not remove the need for impurity testing. Synthetic routes can introduce different residual compounds.

Carrier composition

The proportions of PG, VG and water may be checked alongside density, viscosity and other physical properties.

Stability

Stability testing examines whether the liquid remains within specification during storage.

It may monitor:

• Nicotine concentration
• Acid concentration
• Colour changes
• Nicotine degradation
• Flavour changes
• Precipitation
• Packaging compatibility
• Leakage
• Aerosol emissions

The contents of the bottle are not necessarily identical to the substances produced when the liquid is heated.

Testing may examine:

• Nicotine delivery
• Carbonyl compounds
• Volatile organic compounds
• Metals
• Acid transfer
• Particle characteristics
• Other potentially harmful constituents

Research comparing liquids made with different organic acids has found differences in the resulting aerosol composition, reinforcing the need to test the complete liquid-and-device system rather than the e-liquid alone.

Step 8: Filling and packaging

After the batch has passed its required checks, it can be transferred to the filling line.

Depending on the product, the liquid may be filled into:

• 10ml refill bottles
• Prefilled pods
• Sealed cartridges
• Other compliant nicotine-containing containers

The filling process is normally controlled to maintain accurate volume and reduce contamination or leakage.

Typical production checks can include:

• Fill-volume verification
• Closure checks
• Leak testing
• Batch coding
• Label inspection
• Packaging inspection
• Finished-unit reconciliation

UK rules for nicotine salt e-liquid

In Great Britain, nicotine salt e-liquids are subject to the same core nicotine-containing e-liquid rules as freebase products.

Under the Tobacco and Related Products Regulations 2016, relevant requirements include:

• A maximum nicotine concentration of 20mg/ml
• A maximum refill-container size of 10ml
• A maximum tank or pod capacity of 2ml
• High-purity ingredients
• Child-resistant packaging
• Tamper-evident packaging
• Protection against leakage and breakage
• Consistent nicotine delivery under normal conditions
• Notification before the product is placed on the market

The regulations also state that ingredients other than nicotine must not pose a risk to human health in heated or unheated form.

The current MHRA guidance for consumer e-cigarette products provides a practical overview of these restrictions.

Compliance therefore involves far more than keeping the liquid at or below 20mg/ml. Ingredient purity, formulation consistency, emissions, packaging and product notification all matter.

Concentrated nicotine requires industrial controls

The nicotine used before dilution is far more concentrated than the nicotine found in a finished retail e-liquid.

It can be absorbed through the skin and may cause serious poisoning following sufficient exposure. Commercial handling therefore requires suitable engineering controls, protective equipment, training and documented procedures.

Measures may include:

• Closed transfer systems
• Chemical-resistant gloves
• Protective clothing
• Eye and face protection
• Local exhaust ventilation
• Spill containment
• Restricted access
• Emergency washing facilities
• Exposure and spill-response procedures

Nicotine salt production should not be treated as a casual home-mixing process.

Common misconceptions about how nic salts are made

Nicotine salts are extracted directly from tobacco

Nicotine can be extracted from tobacco, but the resulting material must be purified. Salt formation is a later stage in which the purified nicotine is combined with an acid.

All nicotine salts use benzoic acid

Benzoic acid is common, but commercial analysis has also identified lactic, levulinic, malic, salicylic and tartaric acids as common alternatives.

Adding acid removes impurities from nicotine

The acid changes nicotine’s protonation state. It does not purify crude nicotine or remove unwanted alkaloids, nitrosamines and degradation products.

All the nicotine becomes fully protonated

Not always. A finished e-liquid may contain both freebase and protonated nicotine, especially where the acid-to-nicotine ratio is below equimolar or the wider formulation, shifts the chemical equilibrium.

A 1:1 weight ratio creates a 1:1 salt

Salt calculations are based on the number of molecules, expressed as a molar ratio. Equal weights of nicotine and acid do not necessarily contain equal numbers of molecules.

A low pH proves that all the nicotine is protonated

A low apparent pH suggests an acidic formulation, but direct pH readings can be unreliable in PG/VG mixtures. Specialist analytical techniques provide a more accurate picture.

Any food-grade acid is suitable for e-liquid

Food suitability relates to ingestion. An e-liquid ingredient also needs to be considered in heated form and in relation to the emissions it may produce.

So, how are nic salts made?

At its simplest, nicotine salt e-liquid is made by combining purified nicotine with an acid and blending the resulting nicotine–acid system into an e-liquid base.

Behind that short explanation sits a much more controlled process:

• Nicotine must be purified and tested.
• The acid has to be selected for the formulation.
• Quantities are calculated by molar ratio.
• Mixing conditions must be carefully controlled to produce an even liquid.
• PG, VG and flavourings are added at controlled levels.
• The finished batch is tested for strength, purity and stability.
• Aerosol emissions and device compatibility also need consideration.
• The product must be packaged and notified in line with MHRA regulations.

There is no single recipe used across the entire industry. Acids differ, ratios vary and some products contain a greater proportion of freebase nicotine than others.

What unites them is the underlying chemistry: an acid donates a proton to nicotine, altering its charge state and creating the formulation known as nicotine salt e-liquid.