What is it? | Sodium Stearate is saponified stearic acid—the sodium salt of stearic acid. |
INCI | Sodium Stearate |
Appearance | Fine white powder |
Usage rate | 0.5–20% |
Texture | Smooth powder |
Scent | Nothing noticeable |
Approximate Melting Point | 245–255° C |
pH | 10–11 |
Charge | Anionic |
Solubility | Water, alcohol, cosmetic esters |
Why do we use it in formulations? | Sodium Stearate has a couple of really neat uses in cosmetics. It functions as a thickener/gelling agent and co-emulsifier. You’ll commonly find it in deodorants, where it is combined with propylene glycol or propanediol to create a solid stick base that actives can be added to. |
Do you need it? | No, but if you have a formulation that calls for it there’s no substitution. |
Refined or unrefined? | Sodium stearate only exists as a refined product. |
Strengths | Excellent thickener/gelling agent. |
Weaknesses | Harder to source than many ingredients, high pH. |
Alternatives & Substitutions | I haven’t found any viable alternatives for sodium stearate when used as a gelling agent with propylene glycol/propanediol.
As a thickener, you might try stearic acid, but keep in mind stearic acid is not water-soluble like sodium stearate is. |
How to Work with It | Slowly sprinkle sodium stearate into the hot aqueous phase to dissolve, whisking to incorporate. |
Storage & Shelf Life | Stored somewhere cool, dark, and dry, sodium stearate should last at least two years. |
Tips, Tricks, and Quirks | Sodium stearate + propylene glycol or propanediol creates a very cool semi-translucent gelled solid! |
Recommended starter amount | 100g (3.5oz) or less. |
Where to Buy it | Buy it from an online DIY ingredient supplier or Amazon. |