Glyceryl Stearate

Overview

Plain Glyceryl Stearate (no “SE”, no “PEG-100”) is a single-ingredient ester made from vegetable glycerin and stearic acid. It comes as off-white flakes or pastilles that melt around 55-60 C. Chemically it is a partial mono-glyceride — half a fat molecule, with one stearic acid arm and two free hydroxyl groups.

The most important thing to understand about plain Glyceryl Stearate is what it is not: it is not a complete emulsifier. It cannot hold an oil-water system together on its own. The closely-named variants — Glyceryl Stearate SE (self-emulsifying, contains a small amount of sodium or potassium stearate as the actual emulsifying part) and Glyceryl Stearate (and) PEG-100 Stearate (a popular combo emulsifier) — can. Plain Glyceryl Stearate is the co-emulsifier and texture-builder you add alongside one of those, or alongside e-wax, Polawax, BTMS, etc.

Confusion between these three “Glyceryl Stearate” variants causes more lotion failures than almost any other ingredient mix-up. Check the supplier’s INCI carefully before you buy.

What it does in a formula

Primary role: co-emulsifier. It works alongside a true emulsifier to stabilize the system, reinforce the oil-water interface, and prevent separation in storage.

Secondary roles: emollient (softens skin), light thickening, opacifier (gives a creamy white look to clear gels and emulsions), and a soft, cushioned skin feel. It is non-ionic, so it plays well with anionic, cationic, and amphoteric ingredients alike.

How to use

Use it at 1-5% of the total formula, almost always paired with a primary emulsifier. Typical pairings:

• With e-wax or Polawax at 4-5%, add Glyceryl Stearate at 1-2% to thicken and improve skin feel.
• With Olivem 1000 or Montanov 68 at 4-5%, add 1-2% Glyceryl Stearate to reinforce the lamellar texture.
• With Glyceryl Stearate (and) PEG-100 Stearate (the combo emulsifier), the GS is already in the blend — you do not need to add more.

Add it to the oil phase along with your primary emulsifier and other lipids. Heat the oil phase and water phase to 70-75 C, hold for 20 minutes, combine while blending, then cool with gentle stirring.

Best for / Worst for

Best for: pairing with another emulsifier to improve texture, body creams, hand creams, sun-care lotions, formulas where you want a softer, more cushioned skin feel.

Worst for: solo use as a primary emulsifier — the lotion will separate. Also a poor fit for very clear gels (it adds opacity), and for ultra-light gel-cream textures (it adds body and richness you may not want).

Common pitfalls

The number-one pitfall is using it as a primary emulsifier because the name sounds like it should be one. Plain Glyceryl Stearate alone cannot stabilize an oil-water system at any percentage. You will get a beautiful-looking cream that splits into oil and water within 24-72 hours.

The number-two pitfall is confusing the three variants:

• Plain Glyceryl Stearate — co-emulsifier only.
• Glyceryl Stearate SE — self-emulsifying, anionic, can work alone at 5-10%.
• Glyceryl Stearate (and) PEG-100 Stearate — a complete non-ionic emulsifier blend, can work alone at 4-8%.

All three are sold under similar-looking labels. Always check the full INCI.

Note: some suppliers list both plain Glyceryl Stearate and the self-emulsifying version under the same simplified INCI “Glyceryl Stearate” — even when the product page describes it as “autoemulsionante” (self-emulsifying). If you are buying from a supplier that does this, read the product description (look for “SE” or “autoemulsionante”) rather than relying on the INCI alone.

Third pitfall: adding it after the emulsion has formed. It melts at 55-60 C, so it must go into the heated oil phase. Adding it during cool-down produces gritty white specks that never integrate.

Substitutes

• Glyceryl Stearate SE — same molecule with built-in emulsifying salts. Works solo at 5-10%.
• Cetearyl Alcohol — fatty alcohol co-thickener with similar role, slightly different feel.
• Cetyl Alcohol — lighter co-thickener, silkier finish.
• Stearic Acid — denser, more matte co-thickener for body butters and balms.