Oxothiazolidinecarboxylic acid (procysteine) is a cysteine derivative used in skincare as a precursor that can support intracellular glutathione synthesis, valued for its antioxidant and skin-conditioning properties. It is sometimes included in formulations targeting oxidative stress and skin brightening.
| Reported effect | How often | Notes |
|---|---|---|
Mild skin irritation | Uncommon | Transient redness or stinging, typically at higher concentrations or on sensitive skin. |
Contact dermatitis | Rare | Allergic or irritant reaction reported in isolated cases. |
Sulfur-like odor sensitivity | Rare | As a sulfur-containing compound, faint odor may be noticed but rarely causes adverse reaction. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.