At a glance
- CAS number
- 1310-73-2
- INCI name
- Sodium Hydroxide
- Function
- ph_adjuster, denaturant, saponifying agent
- Typical use level
- 0.01%–5%
- Solubility
- water
CAS number and synonyms are sourced from PubChem. Function, usage levels, pH and compatibility are AI-assisted formulation guidance — verify against your supplier's technical data sheet and applicable regulations before use.
Also known as
Caustic soda Sodium hydrate Aetznatron Soda lye White caustic Soda, caustic Natriumhydroxid Rohrputz Plung Collo-Grillrein Collo-Tapetta Sodium hydroxide (Na(OH))
Compatibility
Works well with:
Water Carbomer Acrylates Copolymer Xanthan Gum Glycerin Fatty Acids
Use caution with:
L-Ascorbic Acid Citric Acid Lactic Acid Salicylic Acid AHAs Retinol Niacinamide (high conc.) Zinc compounds Aluminum compounds
Sodium Hydroxide is strongly alkaline and will neutralize acids directly, degrading acid-sensitive actives such as Vitamin C or AHAs if not carefully sequenced during formulation. It reacts with fatty acids to form soaps (saponification), which can be intentional in cleansers but undesirable in emollient-rich leave-on formulas. Always add to water phase in dilute form and adjust pH incrementally to avoid localized over-alkalinization.
Formulation notes
EU Cosmetics Regulation restricts final product pH rather than concentration directly; must not be used in concentrations that result in a dangerously high final pH. Typically used as a dilute solution (10–18% w/w stock) for safe handling. Final formulation pH should remain within skin-compatible range (approx. 4.0–8.0 depending on product type). Classified as a denaturant and pH adjuster by INCI; handle with appropriate PPE as it is corrosive in concentrated form.
Related ingredients
- TriethanolaminePh Adjuster
- Ascorbic AcidAntioxidant
- Glycolic AcidActive
- Phytic AcidChelator
- Sodium BenzoatePreservative
- Sodium GluconateChelator