Setostearil Alkol — Frequently Asked Questions

They give the approximate ratio of cetyl (C16) to stearyl (C18) alcohol. A 30:70 grade is stearyl-rich and gives firmer, more heat-stable creams and conditioners. A 50:50 grade gives a balanced body, and a 70:30 grade is lighter. The exact ratio varies within a range, so the certificate of analysis should report the gas chromatography result. When you move between suppliers, match the ratio, not just the name.

Chains of mixed length pack together less perfectly than chains of a single length. With an emulsifier and water, that forms a more flexible and stable lamellar gel network. In practice, creams made with the blend tend to have a creamier body and to resist thinning, graininess or separation in storage better than those made with a single alcohol. That is why the blend is the standard choice for many emulsions and conditioners.

No. The Ph. Eur. monograph requires at least 40% stearyl alcohol and at least 90% cetyl plus stearyl alcohol, along with limits on hydroxyl, acid, iodine and saponification values. A cetyl-rich 70:30 blend does not meet the stearyl minimum, although it is a perfectly good cosmetic grade. For medicines, specify the monograph, and check that the certificate of analysis shows compliance for the lot supplied.

Typical levels are around 1–5% in lotions and light creams, and higher in thick creams and rinse-off conditioners, depending on the emulsifier system and the target viscosity. The ratio of fatty alcohol to emulsifier matters as much as the absolute level, because together they form the gel network. Start from your existing formulation or a supplier formulation guide, and confirm the result with stability testing at elevated temperature.

No. Emulsifying wax is a ready-made blend that contains cetostearyl alcohol plus an emulsifier. The anionic type uses sodium lauryl sulphate, and the non-ionic types use ethoxylated emulsifiers such as polysorbates or ceteareth. Cetostearyl alcohol on its own is a co-emulsifier and thickener. It stabilises emulsions but does not emulsify oil and water by itself, so it has to be paired with a primary emulsifier.

Keep bags closed and stacked to a limited height in a cool, dry store away from heat sources, because warmth and pressure make flakes and pastilles fuse into lumps. Fatty alcohols can take up odours, so keep them away from perfumes and solvents. Use stock first in, first out. Material that has caked is usually chemically unchanged, but it is harder to dose, so melt it in full rather than breaking up lumps by hand.