Ceteareth-20

Overview

Ceteareth-20 is an ethoxylated fatty alcohol — specifically a blend of cetyl and stearyl alcohols bonded to about 20 units of ethylene oxide. That ethylene oxide chain is what gives it a high HLB value of roughly 15.5, making it strongly hydrophilic and well suited to holding oil droplets inside a continuous water phase. The result is classic oil-in-water emulsions: white, opaque, elegant lotions that absorb cleanly.

As a non-ionic emulsifier, it carries no charge, which means it plays well across a wide pH range and is unlikely to react with cationic or anionic ingredients in your formula. It is one of the workhorses of mainstream cosmetic manufacturing and shows up on the ingredient lists of countless commercial moisturizers and body lotions.

Because it is PEG-based (the ethoxylation process creates a polyethylene glycol linkage), some “clean beauty” formulations avoid it. Whether that matters to your brand positioning is a separate conversation — from a functional and safety standpoint, Ceteareth-20 has a long, well-documented track record.

What it does in a formula

Ceteareth-20 sits at the oil-water interface, lowering surface tension so that oil droplets remain finely dispersed throughout the water phase instead of separating. On its own it can hold a light emulsion together, but it really shines when paired with a low-HLB co-emulsifier such as cetearyl alcohol or glyceryl stearate. That pairing creates a mixed-emulsifier system with better long-term stability and a richer body.

The finished texture tends to be smooth, white, and creamy — the classic “luxury lotion” look. It also contributes a slight thickening effect, though not enough to replace a dedicated thickener if you need a stiff cream.

How to use

Melt Ceteareth-20 into your oil phase at 70-75 C alongside your oils and any co-emulsifier. Heat the water phase to the same temperature, then combine them with high-shear mixing or vigorous stick-blending.

Typical usage rates:

• Light lotions: 2-3% Ceteareth-20 + 2-3% cetearyl alcohol
• Medium-body creams: 3-4% Ceteareth-20 + 3-5% cetearyl alcohol
• Rich creams: 4-5% Ceteareth-20 + 4-6% cetearyl alcohol or glyceryl stearate

Always pair it with a co-emulsifier. Ceteareth-20 alone at 2-3% can hold a light lotion, but stability over weeks drops without the low-HLB partner.

Best for / Worst for

Best for: classic O/W lotions and creams, body moisturizers, facial day creams, formulas that need a white opaque finish, beginners who want a reliable and forgiving emulsifier system.

Worst for: water-in-oil formulations (HLB is too high), “PEG-free” or “clean beauty” product lines, anhydrous products (no water phase to emulsify into), leave-on products where a completely invisible finish is required.

Common pitfalls

Skipping the co-emulsifier. Ceteareth-20 at 3% alone will technically emulsify, but the result separates within days or weeks. Pair it with cetearyl alcohol or glyceryl stearate for real-world stability.

Mismatched phase temperatures. If the oil phase is at 75 C and the water phase is at 50 C, the emulsifier crystallizes on contact and you get a grainy mess. Match your phases within a few degrees.

Using it in W/O formulas. HLB 15.5 is firmly in O/W territory. If you want a water-in-oil system, you need a low-HLB emulsifier like sorbitan stearate or an appropriate wax.

Over-thickening. Ceteareth-20 + cetearyl alcohol at the upper end of usage can produce a very stiff cream. If that happens, reduce the co-emulsifier before reducing the primary emulsifier.

Substitutes

• Polysorbate 60 — similar HLB (~14.9), also non-ionic and PEG-based, but produces a slightly lighter body.
• Steareth-21 — comparable HLB, typically used with its own co-emulsifier (Steareth-2) as a self-emulsifying pair.
• Olivem 1000 (Cetearyl Olivate + Sorbitan Olivate) — PEG-free alternative with a different skin feel, derived from olive chemistry.
• Emulsifying Wax NF (Cetearyl Alcohol + Polysorbate 60) — pre-blended emulsifier system that does the same job in one pellet.