preservative
Potassium Sorbate
A widely used cosmetic preservative with established safety record, accepted across natural, organic, and clean-beauty frameworks. Typically combined with sodium benzoate, phenoxyethanol, or benzyl alcohol for broad-spectrum coverage.
Benefits
- Effective against mould, yeast, and some bacteria
- COSMOS-certified in natural and organic formulations
- Food-grade safety record
- Low sensitisation potential
- Broad use concentration range
Example uses
- Natural certified face creams
- Body oils
- Eyeshadow sticks
- Mascara formulas
- K-beauty serums
Mechanism of action
Sorbic acid (the active undissociated form of potassium sorbate at low pH) inhibits key mould and yeast enzymes — particularly dehydrogenases — blocking energy metabolism. The inhibition is more selective for fungi than bacteria, explaining the need for co-preservation against gram-negative and gram-positive organisms.
Clinical evidence · High
Extensively characterised preservative with GRAS food-grade status and multiple SCCS cosmetic safety assessments.
Effective concentration range
0.1–0.5%
Formulation notes
Most effective at pH <6. Above pH 6, efficacy decreases markedly. Must be combined with antibacterial agent for full-spectrum coverage. Incompatible with some protein-based actives at high concentrations.
Watchouts
At pH >6 has significantly reduced efficacy — frequent source of under-preservation when formulations are not pH-tested. Some dermatitis case reports in individuals with sorbate sensitivity.
Controversies & overclaims
Under-preservation risk at pH >6 is a formulation failure mode that causes product contamination in improperly buffered natural formulations. This limitation is not always communicated.
Market positioning
Sold as the ideal natural preservative. Correct for its spectrum and pH range. The pH dependency limitation is a formulation reality that should inform consumer expectations.
Comedogenicity
0 / 5
Sensitisation risk
Low
INCI & aliases
Potassium Sorbate
sorbic acid potassium salt · potassium (E,E)-hexa-2,4-dienoate
Clean beauty perception
Universally accepted in clean beauty, including strict natural and COSMOS-certified formulations. EWG rating 1. One of the most trusted clean-beauty preservatives.
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