Safe Use Level of CoCool™ in Lip Gloss Without Irritation
Question
Good afternoon,
I have purchased your product CoCool™ (Menthol + Menthyl Lactate) and would like to use it in a lip gloss formulation. My question is whether this ingredient is safe for use on the lips and, if so, at what concentration it can be used in this area without causing irritation.
Thank you.
Answer
Yes, CoCool™ (Menthol+Menthyl Lactate, e.q.Frescolat Plus) can be used in a lip gloss, provided it is fully dissolved in the oil-compatible phase and the finished product passes irritation/compatibility testing.
Recommended lip-gloss use level
- First lab trial: start at 0.1–0.2% CoCool™.
- Practical development range for most lip glosses: 0.1–0.5% CoCool™.
- Increase gradually only if the cooling effect is not strong enough. Around 0.3–0.5% is usually already noticeable for lip use.
- 1% may be possible only after successful irritation/in-use testing, but it should not be the first trial level for a leave-on lip product.
Our catalog usage range for CoCool™ is 0.1–5% for general cosmetic cooling applications, but the lip area is more sensitive than normal skin. Therefore, the upper end of the catalog range should not be treated as the recommended lip-gloss level. At 5% CoCool™, the formula would contain about 2.5% menthol + 2.5% menthyl lactate, which can be too strong for many lip products and may cause stinging, burning, or irritation.
Formulation notes
- CoCool™ is oil/glycol/ethyl alcohol soluble; it is not intended to be added directly into a water phase.
- Add it into the oil-compatible phase and mix until it is completely dissolved and the batch is clear with no sediment.
- Use low-speed mixing and keep the vessel covered as much as practical during mixing, because menthol is volatile.
- If the formula also contains flavor, fragrance, essential oils, alcohol, acids, warming/cooling agents, or other potentially irritating sensorial ingredients, use the lower end of the range.
- Check clarity after 24–48 hours and after temperature cycling; haze, crystallization, or sediment indicates incomplete solubilization or too high a level for the oil system.
Because irritation depends on the complete formula and individual sensitivity, we cannot guarantee a level that will cause “no irritation” for all users. Please run patch testing and final-product lip in-use testing before commercial release, especially if using above 0.5%.
