Menthol is the classic cooling ingredient, but it is no longer the only one. Synthetic “cooling agents” such as WS-3 and WS-23 give a cold feel with little or no mint smell. Many products now combine them with menthol. This guide compares the main options.
How cooling works
Menthol and the synthetic coolants work on the same receptor, TRPM8, the nerve sensor that normally responds to cold. They differ in how strongly and how quickly they trigger it, how long the effect lasts, and what else you taste and smell.
The main options
| Ingredient | CAS | FEMA GRAS | Profile |
|---|---|---|---|
| L-menthol | 2216-51-5 | 2665 | Strong cooling with a characteristic mint odour; at high doses can feel hot or stinging |
| WS-3 (N-ethyl-p-menthane-3-carboxamide) | 39711-79-0 | 3455 | Almost odourless; cooling that builds slowly and lingers |
| WS-23 (2-isopropyl-N,2,3-trimethylbutyramide) | 51115-67-4 | 3804 | Little taste or smell; marketed for a quick, clean cool |
| WS-5 (N-[(ethoxycarbonyl)methyl]-p-menthane-3-carboxamide) | 68489-14-5 | 4309 | Reported to be several times stronger than WS-3 |
| L-menthyl lactate | 59259-38-0 | 3748 | Faintly minty, virtually tasteless, long-lasting cooling |
In laboratory receptor tests, menthyl lactate, WS-3 and L-menthol activate TRPM8 at similar low concentrations, while WS-23 needs a much higher one. Receptor data do not translate directly into perceived cooling, so formulators always test in the finished product.
When formulators choose each
- Menthol when the mint note is wanted: toothpaste, mouthwash, mint confectionery, chewing gum and mint flavours. It also supports a natural label.
- Synthetic coolants when cooling is wanted without mint: fruit-flavoured gum, beverages, skin care, or to extend the cooling of a mint flavour without adding more mint smell.
- Blends of menthol with WS-3 or menthyl lactate to lengthen cooling while keeping a natural mint character.
The regulatory picture is changing
- Natural labelling. Under EU Regulation (EC) No 1334/2008, a flavouring labelled natural may contain only natural flavouring substances or preparations, made by physical, enzymatic or microbiological processes. Synthetic coolants are made by chemical synthesis, so they cannot form part of a natural flavouring. L-menthol from mint can.
- Nicotine products. Regulators are looking closely at cooling agents in e-cigarettes and nicotine pouches. Germany’s Federal Institute for Risk Assessment (BfR) recommended in 2025 that WS-3, WS-23 and WS-5 be banned from e-liquids, and in October 2026 proposed maximum levels for twelve coolants, including menthol. Check current rules in each market before formulating.
Our view
Synthetic coolants are useful tools, but they do not replace the flavour of mint or a natural label. If your product needs both cooling and a natural mint character, natural L-menthol remains the base. L-Menthol Crystals · Uses of natural menthol.
Sources: FEMA GRAS listings; JECFA; EU Regulation (EC) No 1334/2008; Behrendt et al., British Journal of Pharmacology (2004); Leffingwell & Associates; BfR opinions 010/2025 and 054/2026.
