What it is
Sodium sulfite is a water-soluble white salt that readily gives up electrons, making it an effective oxygen scavenger and reducing agent. In cosmetics it is added at low concentrations to slow oxidation of easily degraded actives and to help maintain product color and stability. It also has some preservative-supporting activity in certain systems.
Safety & warnings
Sulfites can provoke reactions in sulfite-sensitive individuals and are recognized contact allergens for a subset of people. They are used at low levels in cosmetics. Sodium sulfite is not considered comedogenic.
Origin & sourcing
A synthetic inorganic salt manufactured industrially, typically by reacting sulfur dioxide with sodium carbonate or sodium hydroxide.
Questions everyone asks
Why is sodium sulfite added to skincare?
It works as an antioxidant and reducing agent, protecting oxidation-prone ingredients and helping keep the formula stable and consistent in color.
Can it cause sensitivity?
Sulfites are known contact allergens for some people, so those with a sulfite sensitivity may want to patch test before use.