At a glance
- CAS number
- 77-92-9
- INCI name
- Citric Acid
- Function
- ph_adjuster, chelator, antioxidant, preservative_booster, exfoliant
- Typical use level
- 0.1%–10%
- Solubility
- water
- Stable pH
- 2–6.5
CAS number and synonyms are sourced from PubChem. Function, usage levels, pH and compatibility are AI-assisted formulation guidance — verify against your supplier's technical data sheet and applicable regulations before use.
Also known as
citric acid 2-hydroxypropane-1,2,3-tricarboxylic acid Citric acid, anhydrous Aciletten Anhydrous citric acid Citro Citretten Citric acid anhydrous Chemfill Hydrocerol A 1,2,3-Propanetricarboxylic acid, 2-hydroxy- 2-hydroxy-1,2,3-propanetricarboxylic acid
Compatibility
Works well with:
Niacinamide Hyaluronic Acid Glycerin AHA Acids Sodium Citrate Vitamin C (L-Ascorbic Acid) Kojic Acid Allantoin Panthenol Preservatives (Phenoxyethanol)
Use caution with:
Sodium Bicarbonate Calcium Carbonate Strong Bases (Sodium Hydroxide at high conc.) Oxidizing Agents Retinol (at high conc.)
Citric acid reacts with carbonates and bicarbonates causing effervescence and neutralization, making pH control unpredictable. It can chelate divalent metal ions, which may destabilize formulations relying on calcium or magnesium for structural integrity. At very low pH levels it may accelerate degradation of sensitive actives such as retinol.
Formulation notes
Classified as an AHA at higher concentrations (above ~3%); EU cosmetics regulations require labeling warnings for AHA-containing products above certain thresholds. At low levels (0.1–0.5%) primarily used as a pH adjuster/buffer. Use caution on sensitive or compromised skin at elevated concentrations. Generally recognized as safe (GRAS) by the FDA.
Related ingredients
- Phytic AcidChelator
- Lactic AcidPh Adjuster
- TriethanolaminePh Adjuster
- Ascorbic AcidAntioxidant
- Glycolic AcidActive
- Sodium GluconateChelator