Ammonium Hydroxide
Ammonium hydroxide is a mild alkaline ingredient used in very small amounts in cosmetics and hair products to adjust pH levels. It helps stabilise formulas and is most commonly found in hair dyes and some cleansers. In the UK it is strictly regulated so that only safe, low concentrations are allowed in beauty products.
How it works in skincare
In cosmetics and skincare, ammonium hydroxide functions primarily as a pH adjuster, bringing formulations into the optimal acidity or alkalinity range for stability and effectiveness. It can also act as a buffering agent in hair colourants, helping the cuticle layer open slightly so pigments can penetrate the hair shaft more evenly. At the low levels permitted in UK and EU cosmetic regulations it evaporates quickly, leaving no residue on skin or hair.
Key benefits
- Helps stabilise product pH for better shelf life
- Assists even colour development in permanent hair dyes
- Improves lather and cleansing efficiency in some shampoos
- Enhances the performance of other active ingredients
- Allows gentle cuticle lifting in hair without excessive damage
- Contributes to consistent texture in creams and lotions
Best for
normal skin, oily skin, hair that requires colouring
Where it comes from
Ammonium hydroxide is produced by dissolving ammonia gas in water. While ammonia can occur naturally from the breakdown of organic matter, the cosmetic-grade version is manufactured synthetically under controlled conditions to meet strict UK and EU purity standards.