Material guide: WS-3 — its job is not to smell like anything, and its flavour field uses the word "trigeminal"

About 5 minutes.

Short version

• Name: WS-3, formally N-ethyl-2-isopropyl-5-methylcyclohexanecarboxamide, CAS 39711-79-0
• Formula C13H25NO, MW 211.35; FEMA 3455, JECFA 1601, FLAVIS 16.013, CoE 2298
• Odour type: minty; odour: mentholic, minty, alcoholic, cooling
• Strength: low, rank 1; vapour pressure 0.000085 mmHg
• Appearance: white to pale yellow crystalline solid, melting point 91–93 °C
• Suppliers: 36; the occurrence field reads "not found in nature"
• Notes field: "Physiological coolant used in foods, beverages, chewing gum, toiletries, topical pharmaceutical formulations and oral hygiene products"
• All three toxicity fields read "Not determined"

The two describers disagree, and the difference is dose

The odour description field carries three passages:

Luebke (2009): at 25.00% in dipropylene glycol. mild mentholic minty.

Mosciano (2000): at 10.00%. Virtually odorless being slightly alcoholic and cooling.

(unattributed): MILD MINTY, NEARLY ODORLESS.

One says minty, one says virtually odourless — and the concentrations differ 2.5-fold.

For a material whose strength field reads low and whose vapour pressure is 0.000085 mmHg, that gap makes sense. How low is that? Benzophenone sits at 0.001 and Javanol at 0.001 — WS-3 is more than an order of magnitude below them. It barely enters the air.

(Who wrote the odour descriptions in this database, and why you read the concentration before the adjectives, is Who wrote the odour field.)

But none of this matters much, because this material is not for smelling.

The flavour field uses the word "trigeminal"

Mosciano's passage in taste_descriptions reads:

at 10.00 - 100.00 ppm. Intense lingering cooling trigeminal effect. The cooling sensation slowly but steadily grows to a lingering cooling mouth feel with a slightly camphoraceous and minty character.

"Trigeminal" is a rare word in a fragrance description field, and its appearance here is not rhetorical.

Cooling is neither a smell nor a taste — it is a temperature receptor being fooled by a chemical. That thread runs through menthol (the TRPM8 cold receptor), with cinnamaldehyde (TRPA1) and eugenol as two other switches in the same family.

WS-3 is the purified version of that idea. Menthol has both an odour and a cooling effect; WS-3 drops the odour half and keeps the cooling.

• Menthol: odour type minty, with a definite smell
• WS-3: strength field low, vapour pressure an order of magnitude lower, and its cooling effect described as intense and lingering

It is a molecule that separates two effects that usually arrive together.

Klein 2011 gives it a place on a ladder

Klein and colleagues tested two new menthol-derived cooling compounds (GIV1 and GIV2 in the paper) in Chemical Senses in 2011, with WS-3 among their comparators.

The findings come in layers:

• In calcium flux studies of TRPM8 in HEK cells, GIV1 and GIV2 were roughly 40 to 200 times more potent than menthol and WS-3.
• Both also activate TRPA1, but at levels 400 times higher than needed for TRPM8 — so at working doses they essentially only touch TRPM8.
• In calcium imaging of cultured rat trigeminal and dorsal root ganglion cells, subpopulations responded, and the majority of those were also activated by menthol; some additionally responded to the TRPA1 agonist cinnamaldehyde or the TRPV1 agonist capsaicin.
• They also made in vivo single-unit recordings from cold-sensitive neurons in rat trigeminal subnucleus caudalis, which the compounds excited directly.

The paper's subject is those two new compounds; WS-3 is a baseline. But the baseline is useful: it puts WS-3 in menthol's order of potency, not in the newer generation's.

(The paper notes that in earlier human psychophysical work, GIV1 in a toothpaste medium produced a longer-lasting cooling sensation than GIV2 and WS-3. That is a citation rather than their own experiment, and I did not go back to the original study.)

It turns up somewhere you might not expect

Erythropel and colleagues compared e-liquids of one brand sold in six countries by GC/MS in Tobacco Control in 2020, measuring principal flavourants and nicotine.

One finding concerns this material:

EU-marketed "Mint" liquids contained the synthetic coolant N-ethyl-p-menthane-3-carboxamide (WS-3), absent in US/Canadian products.

The same paper records that principal flavourant concentrations were significantly lower in the EU liquids, and that the US/Canadian "Mango" contained triethyl citrate as an emulsifier.

The point here is not e-cigarettes; it is this molecule's distribution. A coolant with 36 suppliers appears in or disappears from one brand's market versions according to the regulatory environment. That is the kind of information a database field cannot show me.

The rest of the family

The database holds more than one coolant:

Name	CAS	Suppliers	Strength field
WS-3	39711-79-0	36	low
WS-23	51115-67-4	25	—
WS-5	68489-14-5	15	—
WS-12	68489-09-8	10	—

The WS numbers are not a potency order — they are development codes. WS-3 is the best-supplied of the group.

How to use it

• It is a solid melting at 91–93 °C. Weigh it and make a solution first. The solubility field lists alcohol; water is 21.38 mg/L.
• It is primarily a flavour and oral-care material. The category field reads flavoring agents, and cosmetic_uses reads only tonic.
• Do not expect an odour contribution. Strength rank 1, vapour pressure 0.000085 mmHg. For mint aroma, use menthol or a mint oil.
• Its effect arrives late and accumulates. Mosciano's description is "slowly but steadily grows" — a different rhythm from evaluating an aroma.
• It carries FEMA, JECFA, FLAVIS and CoE numbers, so its food rules are traceable.

What this doesn't establish

• I have neither tasted nor smelled it. The whole article is fields, database-wide counts and two papers.
• Klein's paper is about GIV1 and GIV2; WS-3 is a comparator. What I take is the relative position it gives WS-3, not any assessment of the new compounds.
• That work is cells and rats. Perceived human intensity and duration cannot be read directly off TRPM8 calcium-flux potency.
• "WS-3 separates odour from cooling" is read off the fields (low strength, low vapour pressure, strongly described cooling), not from a controlled experiment anyone ran.
• Erythropel's team measured products purchased in 2019. Formulations change, and that difference may no longer hold.
• Whether a 2.5-fold concentration difference fully explains "virtually odourless" versus "mild mentholic" is not something I can verify. That is my proposed explanation, not a measurement.
• All three toxicity fields are undetermined, and I did not consult the JECFA or EFSA evaluations.
• Most of the WS family have empty strength fields, so that table cannot be used to compare potency.