Vitamins

Sodium Hydroxide

Also known as: lye

Highly alkaline ingredient | Used in small amounts in cosmetics (such as in exfoliants and cleansers) to adjust pH

Addresses

pH Adjuster/Stabilizer

What Is Sodium Hydroxide?

Sodium hydroxide, also known as lye, is a highly alkaline (also known as “basic”) ingredient used in small amounts in cosmetics to adjust the pH of a product in a formula. This is seen particularly in products such as cleansers and in leave-on exfoliants, where the product’s pH needs to be held within a very specific range for maximum efficacy (between 3-4 is ideal for acid-based exfoliants, while cleansers are generally pH 4.5-6). Pure sodium hydroxide’s pH level is 13, but in cosmetics, it is only used up to pH 11.

Sodium hydroxide is seen in many applications in beauty products, such as nail cuticle solvents and hair straighteners, where it’s used in greater amounts (between 2% and 5% concentrations by weight) than in leave-on skin care products or makeup (for example, some lipsticks contain 0.25% sodium hydroxide). It’s also used as a cleansing and denaturing agent. It’s a significant skin sensitizer in concentrations of 10% or greater.

Benefits for Your Skin

Clinical Evidence & References

Published Research

  • International Journal of Trichology, January-March 2015, pages 2-15 [URL not available]
  • Journal of Cosmetic Dermatology, September 2010, Volume 9, Issue 3, pages 174-184 [URL not available]
  • Acta dermato-venereologica, March 1995, pages 97-101 [URL not available]
  • http://www.cosmeticsinfo.org/ingredient/sodium-hydroxide [http://www.cosmeticsinfo.org/ingredient/sodium-hydroxide]
  • https://www.cir-safety.org/sites/default/files/inorganic%20hydroxides.pdf [https://www.cir-safety.org/sites/default/files/inorganic%20hydroxides.pdf]

Learn More About Skincare Ingredients

Explore our comprehensive ingredient glossary to understand what's in your products.

Browse All Ingredients

Authorised Stockist

Official UK retailer

Tracked Delivery

Free UK shipping over £50

5 Star Rating

Trusted by thousands

Expert Advice

Free consultations