So
Sodium Benzoate
Sodium Benzoate
Salt of benzoic acid. Mild preservative effective at low pH; common in 'natural' formulations.
What it does
Sodium benzoate prevents fungal and yeast growth in low-pH water-based formulations. It needs the formula's pH to be below about 5 to work — at higher pH it loses efficacy. Often paired with potassium sorbate to cover both bacterial and fungal vectors. The natural-skincare market favors this combination because both ingredients are ECOCERT-permitted.
The evidence, graded
expert consensusSodium benzoate is the sodium salt of benzoic acid, used as a preservative across a wide range of cosmetic products. Expert-panel review concluded it can be used safely at concentrations up to 5%, while noting that this ingredient group can produce non-immunologic contact urticaria.Nair 2001 · International journal of toxicology ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
Pairs worth knowing
Browse all 668 ingredients — grouped by what they do, each with whatever evidence we can cite.
This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
Want more like this?
Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.