Sodium Benzoate doesn’t have any great skincare effects and is used for formulation purposes. It’s a corrosion inhibitor, fragrance ingredient, and preservative. It is not a broad-spectrum preservative and it’s used with other preservatives for good efficiency. It’s safe, but people with eczema or a history of skin allergies should use this component with attention.
Citric Acid is one of the AHAs and it is a super useful component! It’s a great antioxidant. It acts as a soft peeling that removes dead cells and kills bacteria. It becomes even more effective if used with other cosmetic acids. Combined formulations are more active, but can irritate sensitive skin if used too often. The component can also whiten the skin and remove dark areas.
It's an exfoliator, meaning it increases UV sensitivity of your skin. That's why it's very important to use sunscreen after it.
Sodium Hydroxide is used mostly for formulation purposes. It helps to hold the pH level of a product. It also works as a chemical exfoliator that removes dead cells. Usually concentration of this component is low in skin care products and it’s used mostly for adjusting pH.