Sodium Hydroxide
Sodium hydroxide
- Role
- Raises the pH of a formula and neutralizes acidic ingredients.
- Catalog formulas
- 6
- Type
- Stability
- Verified
- 06.11.2026
What does this ingredient do in an antiperspirant?
A strong alkali used in cosmetics mainly as a pH adjuster. In small amounts it brings the acidity of the formula to the target value.
Part of a system, not a label in isolation
In antiperspirants it appears where the formula contains acids (for example, mandelic or salicylic acid) and the pH must be set precisely. On its own it has no effect on sweat release.
In the EU, sodium hydroxide is restricted under Annex III of Regulation 1223/2009: when used as a pH adjuster in most products, the pH must stay below 11. The CIR found inorganic hydroxides safe in other uses (apart from hair straighteners and depilatories) when formulated to be non-irritating.
In pure form it is a caustic substance that can cause burns. In a finished cosmetic, what matters is the final pH of the formula, not the mere presence of the hydroxide in the INCI list.
It is not the same as Sodium Chloride (table salt) or Sodium Bicarbonate (baking soda): they have different properties and roles.
Products containing Sodium Hydroxide
Links are based on the complete published INCI list for the exact product version.
Sources
The conclusions apply to the stated conditions and jurisdictions, not automatically to every concentration or product.
- Regulation (EC) 1223/2009, Annex III: alkali metal hydroxides Supports: restrictions
- CIR: Safety Assessment of Inorganic Hydroxides (2021) Supports: function, safety assessment, restrictions
This ingredient is present in the OKEY formula
Verified product
See where it appears in the complete INCI list and compare the full formula across all criteria rather than judging a finished product by one ingredient.
View the OKEY product profile