How much menthol do you need? 0.1 to 5%
The effective menthol percentage, by the vehicle-controlled trials, is 0.1 to 5%; above the 5% ceiling, more stopped adding effect or started adding irritation.
This one works on contact: there is nothing to wait for.
how it was measured
Measured on Cooling and counter-irritant / antipruritic sensation, subject-rated (VAS) on experimentally induced itch; on contact, by mechanism.
0.1%, Gillis 2020.
Gels at 0.1%, 2% and 4.13% menthol against a placebo gel on the upper body of 16 people each felt cooler than placebo in a dose-dependent way, with the effect appearing to saturate around the 2% dose, while irritation rose with dose (Gillis 2020).
What menthol percentage is effective?
Gels at 0.1%, 2% and 4.13% menthol against a placebo gel on the upper body of 16 people each felt cooler than placebo in a dose-dependent way, with the effect appearing to saturate around the 2% dose, while irritation rose with dose (Gillis 2020).
0.1 to 5%
The trials, and what they used
- The job is the cooling sensation, and it has been dosed.
- Gels at 0.1%, 2% and 4.13% menthol against a placebo gel on the upper body of 16 people each felt cooler than placebo in a dose-dependent way, with the effect appearing to saturate around the 2% dose, while irritation rose with dose (Gillis 2020).
- Gels at 0.5%, 4.6% and 10% all lowered skin temperature for an hour in 10 men, and 4.6% felt cooler than both 0.5% and 10%, so 10% bought nothing (Lasanen 2016).
- So the sensation stops growing somewhere between 2% and 4.6%, and the ceiling is set at 5% as the last level shown to add anything.
- Skin blood flow rises with menthol dose with a half-maximal dose of 1% (Craighead 2016), and 40% menthol is the laboratory model for cold pain (Wasner 2004).
- For itch, topical menthol cut histamine itch in 15 volunteers at an unstated percentage (Bromm 1995).
Is more than 5% menthol better?
No: the trials that compared doses put the ceiling at 5%, and above it more stopped adding effect or started adding irritation, so a percentage above 5% reads as above the range, not as stronger.
Neither number settles what more does. The trials that compared doses put the ceiling at 5%: above it, more stopped adding effect or started adding irritation, which is why a declared percentage above 5% reads as above the range, not as stronger.
What does the menthol percentage on a label tell you?
A name that states a percentage ("Menthol 5%") is the only amount a cosmetic label ever declares, so it is the one number that can be read against the trials: inside 0.1 to 5%, above the 5% ceiling, or below the 0.1% floor.
A name without a percentage leaves the position. The rules make a brand list ingredients in descending order of amount down to 1%, and in any order below it, so menthol above the 1% line is at least 1% and menthol below it can be any trace the brand likes. The floor the trials worked from is 0.1%, and a position alone cannot tell you whether a label reaches it.
The menthol percentages in our catalogue
No product in our catalogue is sold on menthol yet.
Read on
- Menthol: the glossary page what it does, who it suits, where it fits
Other actives with a dose the trials pinned:
- Niacinamide 2%+
- Vitamin C (LAA) 5%+
- Retinol 0.075 to 0.3%
- Salicylic acid (BHA) 0.5%+
- Lactic acid 8%+
- Glycolic acid 5%+
- Retinal 0.05 to 0.1%
- Retinyl Retinoate 0.06%+
- Tretinoin 0.025%+
- Adapalene 0.1%+
- Tazarotene 0.045%+
- Azelaic Acid 15%+
- THD Ascorbate 1%+
- Sodium Ascorbyl Phosphate 5%+
- Palmitoyl Pentapeptide-4 0.0003%+
- Caffeine 2%+
- Benzoyl Peroxide 2.5 to 5%
- Tea Tree Oil 5%+
- Hydroquinone 4%+
- Bifida Ferment Lysate 10%+
- Thiamidol 0.2%+
- Cysteamine 5%+
- Peppermint Oil 0.5%+
- N-Acetyl Glucosamine 2%+
- Alpha Lipoic Acid 5%+
- Ammonium lactate 12%+
- Acetylated Hyaluronic Acid 0.1%+
- 4-n-Butylresorcinol 0.1%+
- 4-t-Butylcyclohexanol 0.4%+
- Sphingomonas Ferment Extract 2%+