Science
Mechanism of Action
S-Allylcysteine operates as a powerful antioxidant by directly neutralizing reactive oxygen species (ROS) and reactive nitrogen species (RNS). It enhances the skin's intrinsic antioxidant defenses by activating Nrf2, a key regulator that upregulates protective genes and enzymes. SAC also inhibits prooxidant enzymes such as xanthine oxidase, cyclooxygenase, and NADPH oxidase. Its thiol (-SH) group is crucial, donating a hydrogen atom to prevent lipid and protein oxidation and nitration, while also acting as a metal chelator and radical quencher. Furthermore, SAC supports overall cellular health by preserving mitochondrial function.
Research
Clinical Evidence
Insufficient-data confidenceN/A
Transparency
Dusting Analysis
No information regarding ingredient dusting or common usage percentages for minimal efficacy was found in the provided research data.
The Formula
Formulation
Stability
S-Allylcysteine demonstrates good stability, particularly under acidic conditions, showing no C-S bond cleavage even after 5 days at 50°C in 6 N HCl. However, it can decompose under strong basic conditions (e.g., 2 N NaOH at 50°C for 6 days), forming decomposition products like allylmercaptan and allylsulfide. An aqueous solution of SAC has a reported pH of 5.56 at 24.5°C. The presence of moisture can reduce its solubility if dissolved in DMSO.
Conflicts
- strong basic conditions
Safety
Safety Profile
S-Allylcysteine has not been explicitly reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel or the Scientific Committee on Consumer Safety (SCCS) for cosmetic use. While the U.S. FDA lists it as a 'Flavoring Agent or Adjuvant' and a 'Substance added to food', cosmetic products do not require pre-market FDA approval. Acute and subacute toxicity studies indicate very minor toxicity. However, GHS classification data suggests a potential to 'May cause an allergic skin reaction' (Skin Sens. 1) in approximately 29.9% of reports, which warrants consideration for sensitive skin types.
Your Skin
Skin Compatibility
Our Assessment
Verdict
S-Allylcysteine is a valuable ingredient for its profound antioxidant and anti-inflammatory mechanisms, though specific human clinical data for skin application and precise usage concentrations are currently limited, and a moderate sensitization risk has been noted in some reports.
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