İzopropil miristat — Frequently Asked Questions

Both are light, fast-spreading esters of isopropyl alcohol. Isopropyl myristate is made from C14 myristic acid, and isopropyl palmitate from C16 palmitic acid. IPM is slightly thinner, spreads a little faster and feels lighter, and it stays liquid down to about 3 °C. Isopropyl palmitate feels slightly richer and clouds at a higher temperature. They are often interchangeable, but check feel, cloud point and fragrance solubility when switching.

IPM starts to crystallise at around 3 °C, so in unheated stores or during winter transport it can turn hazy or partly solid. The product is not damaged. Warm the container gently to room temperature and mix it before sampling or use, because the first crystals to form can differ slightly in composition. Store it indoors above about 10 °C to avoid the problem.

IPM has often been rated as comedogenic in older rabbit-ear tests, which are widely considered to overstate the effect in human skin. Real-world effects depend on concentration and on the full formulation. Many body and hair products use it without problems, while some brands limit it in leave-on facial products for acne-prone skin. If you make a non-comedogenic claim, test the finished product rather than relying on ingredient ratings.

IPM is a good solvent for many polymers. It can soften, swell or stress-crack polystyrene, some grades of polyethylene and certain rubbers used in seals and pump parts. Glass, stainless steel and suitable grades of high-density polyethylene and PET are generally used, but compatibility depends on the grade and on the other ingredients. Run storage tests with the final formulation in the final pack, including closures and pumps.

The Ph. Eur. and USP-NF monographs require at least 90% isopropyl myristate, with the remainder mainly related isopropyl esters, plus limits on acid value and other parameters. Most commercial cosmetic grades exceed 98%. For medicines, what matters is monograph compliance and the site documents. For cosmetics, a higher purity gives more consistent feel, odour and cloud point. Specify the minimum ester content you need.

Partly. The myristic acid part, 14 of the 17 carbon atoms, normally comes from palm kernel or coconut oil. The isopropyl part usually comes from petrochemical isopropanol. So a vegetable-based IPM has a high but not complete bio-based carbon content. Bio-based isopropanol exists but is less common. If you need a natural-origin index or a vegan statement, ask for an origin declaration for both raw materials.