Nicotine strength is one of the key considerations when developing an e-liquid range. It determines how much nicotine is contained within the finished product and can influence everything from the type of e-liquid being produced to the strengths and formats offered within a range.
In the UK, e-liquid nicotine strength is typically expressed in milligrams per millilitre (mg/ml). For example, a 10mg e-liquid contains 10 milligrams of nicotine per millilitre of liquid. However, understanding nicotine strength involves more than simply comparing the number on the bottle.
Different e-liquid formats tend to suit different strength ranges, while factors such as nicotine type, formulation and regulatory limits can all affect how a product is developed. For brands, choosing appropriate nicotine strengths is therefore an important part of creating a range that is both commercially coherent and suitable for its intended market.
This guide explains how e-liquid nicotine strengths are measured, the strength levels commonly found in e-liquids and the considerations involved when developing a nicotine strength range.
E-liquid nicotine strength is usually expressed as the amount of nicotine contained in each millilitre of finished e-liquid, written as milligrams per millilitre (mg/ml).
For example:
This measurement describes the concentration of nicotine, rather than the total amount contained within the bottle.
A 10ml bottle of 10mg/ml e-liquid, for instance, contains 100mg of nicotine in total. A 10ml bottle at 20mg/ml contains 200mg in total.
Nicotine concentration can also be expressed as a percentage. As a general conversion, 10mg/ml is equivalent to 1% nicotine.
| Nicotine Strength | Equivalent Percentage |
|---|---|
| 3mg/ml | 0.3% |
| 6mg/ml | 0.6% |
| 10mg/ml | 1.0% |
| 12mg/ml | 1.2% |
| 18mg/ml | 1.8% |
| 20mg/ml | 2.0% |
In the UK, mg/ml is the more commonly used way of displaying e-liquid nicotine strength, and it provides a straightforward basis for comparing the nicotine concentration of different products.
Understanding this distinction is particularly important when developing a range. Bottle size determines the total quantity of nicotine, while mg/ml determines its concentration — and it is the concentration that is normally being referred to when discussing an e-liquid's nicotine strength.
E-liquids are available in a range of nicotine strengths, allowing brands to offer different concentrations within the same product range. The exact strengths available depend on factors including the type of e-liquid, the nicotine used and the market in which the product will be sold.
In the UK, common strengths include 3mg/ml, 6mg/ml, 10mg/ml, 12mg/ml, 18mg/ml and 20mg/ml, although not every format is typically offered at every strength.
Broadly, these can be thought of as different strength bands:
Lower strengths
Lower nicotine concentrations are commonly associated with freebase e-liquids and products intended for devices that produce a greater volume of vapour. They are also frequently used when nicotine is added to larger-format nicotine-free e-liquids.
Mid-range strengths
These concentrations are widely used across modern e-liquid ranges and can be found in both freebase and nicotine salt formulations, depending on the product and intended use.
Higher strengths
Higher nicotine concentrations are commonly found in nicotine salt e-liquids and other products designed to deliver nicotine using relatively small quantities of e-liquid.
These bands are useful for describing a range, but they are not formal classifications. A strength that is considered “high” within one type of e-liquid may be relatively normal within another.
This is why nicotine concentration should not be considered in isolation. E-liquid format, nicotine type and the type of device the formulation is intended for all help determine which strengths make sense within a particular range.
This also sets us up nicely for the following section, where I think we should examine why different e-liquid formats use different nicotine strengths rather than simply continuing to list numbers.
Nicotine strength is closely connected to the type of e-liquid being developed. While the concentration is measured in the same way, different formats are commonly associated with different strength ranges because they are formulated for different products and patterns of use.
Traditional freebase nicotine e-liquids can be produced across a range of nicotine concentrations. Lower strengths such as 3mg/ml and 6mg/ml are particularly common in formulations intended for devices that use more e-liquid and produce greater volumes of vapour.
Higher-strength freebase formulations are also available, although the characteristics of the vapour can become more pronounced as the nicotine concentration increases.
Nicotine salts allow nicotine to be incorporated into formulations with different sensory characteristics to conventional freebase nicotine. This has made them particularly common in higher-strength e-liquids, including 10mg/ml and 20mg/ml products intended for lower-powered devices.
However, nicotine salt does not automatically mean high strength. Salt formulations can also be developed at lower concentrations, depending on the intended product and target range.
Shortfills are larger bottles of nicotine-free e-liquid that intentionally contain space for nicotine to be added separately.
Rather than having a fixed nicotine strength when supplied, their final concentration depends on the volume and strength of the nicotine shot added to the bottle. For example, adding a 10ml 18mg/ml nicotine shot to 50ml of nicotine-free e-liquid produces 60ml of finished e-liquid at approximately 3mg/ml.
This distinction is important when developing an e-liquid range. The question is not simply “Which nicotine strengths should we offer?” but also which strengths make sense for the format, formulation and intended product.
For nicotine-containing e-liquids supplied to consumers in the UK, the maximum permitted nicotine concentration is 20mg/ml (2%).
Under the Tobacco and Related Products Regulations 2016 (TRPR), nicotine-containing e-liquid presented for retail sale must not exceed 20mg of nicotine per millilitre. Nicotine-containing refill containers are also limited to a maximum volume of 10ml.
This regulatory limit has an important influence on how e-liquid ranges are developed. A brand might, for example, offer nicotine salt products at 10mg/ml and 20mg/ml, while a freebase range may use a broader selection of lower concentrations.
The 20mg/ml limit should therefore be treated as a regulatory maximum rather than a target strength. The appropriate concentrations for a product depend on its format, formulation and intended positioning within the wider range.
The TRPR requirements described above specifically govern nicotine-containing e-liquids and refill containers. This is why larger nicotine-free formats such as shortfills can be supplied differently from nicotine-containing 10ml refill bottles.
For brands developing products for the UK market, nicotine concentration is consequently both a formulation decision and a regulatory consideration. Strength, bottle format and the way the finished product will be supplied need to be considered together during product development.
This distinction is particularly relevant when developing a product range. A nicotine strength should not simply be selected because it is commonly available elsewhere in the market. It needs to make sense within the formulation and the type of product for which the e-liquid is being developed.
For manufacturers and brands, nicotine strength is therefore one part of a broader formulation decision rather than a specification that should be considered independently.
Developing a nicotine strength range involves more than offering as many options as possible. Each strength should have a clear role within the wider product range and be appropriate for the e-liquid format being produced.
For brands and manufacturers, several factors can influence that decision:
Freebase, nicotine salt and shortfill products are commonly associated with different nicotine concentrations. The strengths selected should therefore make sense for the particular format rather than being applied uniformly across every product.
The type of device a formulation is designed for is an important consideration. Lower-output pod and mouth-to-lung systems are commonly paired with different nicotine concentrations from higher-output devices because the amount of e-liquid vapourised can differ substantially.
The choice between freebase nicotine and nicotine salts can influence which concentrations are practical within a range. Nicotine salts are commonly used for higher-strength formulations because their sensory characteristics differ from conventional freebase nicotine.
A well-planned range should give each strength a clear purpose. Offering several concentrations that are very close together may add manufacturing and inventory complexity without necessarily creating a meaningful distinction between products.
The strengths that can be supplied vary between markets. Products developed for the UK must remain within the applicable 20mg/ml maximum for nicotine-containing e-liquid sold to consumers, while products intended for other countries may need to meet different requirements.
The objective is therefore not necessarily to create the widest possible selection of nicotine strengths, but to develop a coherent range in which the nicotine type, concentration, e-liquid format and intended product work together.
Choosing the right nicotine strengths is an important part of developing a coherent e-liquid range. The appropriate combination will depend on the e-liquid format, nicotine type, intended product and markets in which it will be sold.
At Own Label Creations, we work with brands to develop e-liquid formulations and product ranges around their specific requirements, from selecting appropriate nicotine strengths and formats through to flavour development and manufacturing.
Whether you're developing a new e-liquid range or expanding an existing one, our team can help turn your product requirements into a finished formulation ready for manufacture.
