Science
Mechanism of Action
This ingredient is created through the fermentation of radish roots by *Leuconostoc kimchii*, a lactic acid bacteria, resulting in a filtrate rich in antimicrobial peptides, amino acids, and organic acids. These components work collectively to inhibit the growth of various harmful microorganisms, encompassing Gram-positive and Gram-negative bacteria, yeast, and fungi. Beyond its preservative function, it moisturizes the skin, supports a balanced skin microbiome by fostering beneficial organisms, and provides mild exfoliation via naturally occurring lactic acid. It may also help mitigate skin inflammation, particularly in sebum-rich areas, benefiting acne-prone skin.
Research
Clinical Evidence
High confidence2.0-4.0%
Key findings
- 01 Minimum Inhibitory Concentration (MIC) studies demonstrated efficacy against various microorganisms: 0.25-2% inhibited *A. brasiliensis*, *C. albicans*, and *S. aeruginosa*; 0.50-4% inhibited *E. coli*; and 1-4% inhibited *P. aeruginosa*.
- 02 Human Repeated Insult Patch Tests (HRIPT) showed no sensitization at a 10% dilution in water (50 subjects) or at 0.04% in an eyebrow gel formulation (105 subjects).
- 03 A concentration of 11% was not classified as a photoirritant, despite exhibiting a significant reduction in cell viability during phototoxicity testing.
Transparency
Dusting Analysis
While this ingredient can provide general product protection at concentrations around 0.5%, its recommended usage rate for robust broad-spectrum preservative efficacy is 2.0-4.0%. Concentrations below 0.25% are unlikely to provide any significant functional benefit, indicating 'dusting'. Products claiming substantial preservative or antimicrobial activity should utilize concentrations within the optimal range.
The Formula
Formulation
Stability
This ingredient demonstrates stability up to 60°C (140°F) and maintains peptide activity across a broad pH range of 2-8, with a notable decrease in activity observed at pH 9. For optimal storage, keep in a sealed container, shielded from direct sunlight, at or near room temperature; freezing should be avoided. Sedimentation may occur, so mix thoroughly prior to use.
Conflicts
- Incompatible with oils (immiscible)
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel concluded that radish root-derived ingredients, including Leuconostoc/Radish Root Ferment Lysate Filtrate, are safe for cosmetic use when formulated to be non-sensitizing. It has shown non-irritating properties in EpiDerm™ tests and was predicted as a non-sensitizer in a DPRA assay. HRIPTs at 10% and 0.04% confirmed its non-sensitizing profile. It was not genotoxic at concentrations up to 5000 µg/plate in an Ames test, nor was it considered a photoirritant at 11% or an ocular irritant. While generally well-tolerated, direct contact with eyes, skin, or inhalation/ingestion may potentially cause irritation in highly sensitive individuals. The EWG notes concerns regarding contamination without providing further details.
Your Skin
Skin Compatibility
Our Assessment
Verdict
As a natural, fermentation-derived ingredient, Leuconostoc/Radish Root Ferment Lysate Filtrate offers effective broad-spectrum preservation, promotes a healthy skin microbiome, and provides conditioning benefits, making it a valuable addition to diverse skincare formulations.
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