INCI Name
Citric Acid
Functions
4 Roles
Sustainability
9/10
Category
ph adjusters
What It Does
Citric Acid is an alpha-hydroxy acid (AHA) naturally found in citrus fruits but commercially produced through fermentation of sugar substrates by Aspergillus niger mold. In cosmetics, it serves as a multifunctional workhorse ingredient, primarily used to adjust and buffer pH to optimal ranges for product stability and skin compatibility, while also chelating metal ions that could otherwise catalyze oxidation and degradation. Formulators favor it for its excellent solubility, clean label appeal, and ability to enhance preservative efficacy while providing mild antioxidant benefits at concentrations typically ranging from 0.01-2%.
Technical Properties
pH Range
2.2-3.5
Optimal working range
Ionic Charge
anionic
Molecular charge type
Viscosity Effect
neutral
Impact on formula thickness
Ingredient Compatibility
Known Interactions
Casein precipitates at pH < 4.6. Citric acid beverages will cause immediate, irreversible curdling. Use plant protein or hydrolyzed whey for acidic drinks.
High concentrations of Citric Acid (pH < 3.5) can kill acid-sensitive probiotic strains (Lactobacillus, Bifidobacterium) during shelf life. Use acid-resistant strains or enteric coating if combining.
Whey protein denatures and precipitates below pH 4.6 (its isoelectric point). Citric acid-based beverages at pH 3-4 will cause visible protein aggregation. Use hydrolyzed whey or plant protein for acidic beverages.
High Calcium + Citric Acid can form calcium citrate precipitate in beverages, causing cloudiness or sedimentation. Manageable with proper formulation (sequestrants, pH control), but test stability.
Sustainability Profile
Sustainability Score
Biodegradability
readily biodegradable
Source
fermentation
Feedstock
corn or sugar-based carbohydrates
Related Ingredients
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Quick Reference
- Full INCI Name
- Citric Acid
- Common Name
- Citrus Peel
- CAS Number
- 77-92-9
- Category
- ph adjusters