The difference between a cosmetic cooling gel and a medicated rub is decided at the bench, by which sensate you choose. Here is how that decision is made, and what it costs you in product performance.
Written & researched by Norpadilah Abd Latif, Chemist & Cosmetic Formulation Contributor, Dr Orizi · Reviewed by Creaton Poh · Published by Dr Orizi (M) Sdn. Bhd., ORIZI Group · Last reviewed August 2026
Disclosure: This article is published by Dr Orizi and may refer to our own manufacturing experience and capabilities. External factual claims are supported by cited sources.
Quick Answer
A cooling gel stays a cosmetic when its effect comes from a sensate — an ingredient that triggers the skin’s cold-sensing receptors without acting pharmacologically. Menthol and its derivatives do this. Analgesic actives such as methyl salicylate and capsaicin do not; they act pharmacologically, which makes the product a medicine requiring registration rather than notification. The formulation task is to deliver a convincing cold sensation using sensates alone.
Key Takeaways
- Menthol produces cold sensation by acting on the skin’s cold-sensitive receptors — a sensory effect, not a pharmacological one.
- Onset and duration are separable: menthol gives a fast, sharp, short cool; menthyl lactate and similar derivatives give a slower, gentler, longer one. Most good formulas use both.
- Menthol’s volatility and poor water solubility dictate the base, the solubiliser and the packaging — not the other way round.
- Warming products use a different mechanism again, typically a warming sensate rather than an active.
- Get the sensate system right and the product performs; reach for an analgesic active and the regulatory route changes entirely.
What actually creates the cold
Cooling in a topical product is a sensory illusion, and a well-documented one. Menthol interacts with the cold-and-menthol-sensitive receptor in sensory nerve endings in the skin — the same receptor that responds to a genuine drop in temperature. The skin is not actually colder. The nerve simply reports that it is.
This matters commercially as well as scientifically. Because the effect is sensory rather than pharmacological, it sits within the cosmetic definition — and because it is immediate and unmistakable, it is the easiest product experience in personal care to demonstrate to a customer.
The trade-off is that sensation is all you get. A sensate makes the area feel cool and comfortable; it does not act on the underlying tissue, and the product’s language has to reflect that.
Choosing the sensate system
Treating “cooling” as a single property is the most common formulation mistake in this category. Onset, intensity and duration are three different specifications, and different materials deliver them.
| Material | Character | Formulation notes |
|---|---|---|
| Menthol (crystalline) | Fast onset, sharp, relatively short-lived; strong minty odour | Volatile and poorly water-soluble — needs a solvent or solubiliser and a closed pack |
| Menthyl lactate | Slower onset, milder, notably longer-lasting; very low odour | Used to extend the cooling after the menthol has flashed off |
| Peppermint oil | Contributes both cooling and the expected scent signature | Natural variability; contributes to the fragrance allergen profile |
| Ethanol (where used) | Adds an evaporative cooling effect on application | Can be drying and can sting; changes the pack requirement |
A gel built on menthol alone feels dramatic for two minutes and then flat, which reads to the customer as the product “wearing off” too quickly. A gel built on menthyl lactate alone feels weak on first application because nothing happens fast enough. Combining a fast material with a long one produces the cooling curve people actually describe as good: immediate, then sustained.
Why the base is dictated by the sensate
Menthol is a crystalline solid with low water solubility and appreciable volatility, and those two properties drive most of the formulation decisions in an aqueous gel.
- Dissolution. Menthol must be dissolved before it goes into the water phase — typically into a glycol, a mild solvent or a solubilising system — or it will recrystallise, showing up as gritty particles in the finished gel.
- Gelling system. Carbomer-type thickeners are neutralised into a clear gel and are sensitive to electrolytes and to pH; the solubiliser chosen for the menthol has to be compatible with that system or the gel loses clarity and viscosity.
- Packaging. A volatile sensate escapes through a poorly chosen closure or liner. A product that cooled well at production and weakly at month twelve is usually a packaging problem, not a formula problem.
- Skin comfort. Raising the menthol level to strengthen the effect also raises the sting on freshly shaved, broken or sun-exposed skin. Soothing components and a well-buffered base widen the comfort window.
These are the reasons a cooling gel is a harder brief than a body lotion despite having a shorter ingredient list. Nothing in it is decorative.
Warming products work differently
A warming balm is not a cooling gel in reverse. The pleasant, slow-building warmth in a cosmetic massage product typically comes from a warming sensate such as vanillyl butyl ether, whose intensity is controlled by concentration and by the base it sits in. A fat- or wax-based balm holds the material at the skin surface and gives the massage slip the format is bought for.
Capsaicin, by contrast, is an analgesic active with a pharmacological mode of action. It produces a stronger and longer effect, and it changes the product’s regulatory category.
The line, stated plainly
| Approach | Mechanism | Consequence |
|---|---|---|
| Menthol, menthyl lactate, peppermint, vanillyl butyl ether | Sensory stimulation of skin receptors | Cosmetic — notified with NPRA |
| Methyl salicylate, capsaicin, topical NSAIDs | Pharmacological action | Medicine — requires product registration |
NPRA’s classification criteria make the distinction the deciding one: a drug acts by pharmacological, immunological or metabolic means, while a cosmetic is applied to external parts of the body mainly to clean, perfume, change appearance, correct body odour, protect or keep them in good condition, and may not be presented as treating disease.
In practice this means the brief has to be settled before the bench work starts. Reformulating a cooling gel to remove an analgesic active late in development is not a small edit — it changes the sensory profile the brand has already approved, and usually the packaging too.
What we check before a cooling gel is signed off
From our formulation work at Dr Orizi, four checks catch most of the problems that would otherwise surface after launch:
- The cooling curve, not the cooling peak. Panel assessment at application, at five minutes and at thirty minutes — a formula that only performs at minute one will be described as weak.
- Recrystallisation on temperature cycling. Menthol that comes out of solution after a cold night in transport is a visible, unsellable defect.
- Sensate loss in the actual pack. Stability has to be run in the packaging the brand intends to use, not in a laboratory jar.
- Comfort on compromised skin. Real users apply relief products to legs that were shaved that morning.
Limitation: these are our development practices. Specific formulations differ, and ingredient levels must comply with the permitted cosmetic ingredient annexes in force at the time of manufacture.
Frequently asked questions
Does a cosmetic cooling gel actually reduce skin temperature?
Not meaningfully. The cold is a sensory response — the skin’s cold receptors are stimulated by the sensate. Products intended to physically remove heat, such as cold packs and cooling patches, work by a different mechanism and are regulated as medical devices.
Why does my cooling gel feel strong at first and then disappear?
That is the signature of a formula relying on menthol alone. Menthol is fast and volatile. Adding a longer-lasting cooling material such as menthyl lactate extends the effect after the initial hit fades.
What causes gritty particles in a cooling gel?
Usually menthol recrystallising because it was not properly solubilised, or because the product went through a temperature cycle the formula was not designed for. It is a formulation and stability issue rather than a contamination issue.
Can I get a stronger cooling effect without changing category?
Yes, within limits — through the sensate combination, the base and the level of volatile solvent, all kept within permitted cosmetic ingredient levels. What you cannot do is add an analgesic active, because that changes the regulatory category rather than just the intensity.
Is a warming balm safer to formulate than a cooling gel?
It is generally more forgiving on stability, because a wax-and-butter base is less prone to the solubility and recrystallisation problems of an aqueous menthol gel. The warming sensate level needs careful control, as tolerance varies more between individuals than it does for cooling.
Sources & references
- NPRA — Medical Device–Drug–Cosmetic Interphase classification criteria — the pharmacological, immunological and metabolic test quoted above.
- NPRA — Guidelines for Control of Cosmetic Products in Malaysia — the cosmetic definition, notification framework and ingredient annexes.
- NPRA — Guideline for Cosmetic Claims — what a cosmetic relief product may and may not say.
Update history
August 2026 — First published.
Related reading: for the commercial side of the same decision — which registration route a product falls into and how long each takes — see ORIZI Group’s guide to cosmetic notification, MAL and MDA registration for pain relief products, and the companion guide on label claims and product names.
