Lactoperoxidase

Lactoperoxidase is an enzyme used at low levels in oral-care and some preservative/antimicrobial systems; enzymes are proteins that can irritate compromised skin and have a recognized (though uncommon) potential for delayed sensitization in reactive individuals. While generally well-tolerated at typical cosmetic concentrations, the combination of enzymatic activity and allergy history (often dairy-derived protein) warrants a mild-risk score, especially for eczema-prone or barrier-impaired patients. Safety Notes: In consumer skincare, lactoperoxidase is typically used as part of enzyme-based antimicrobial/“preservative-support” systems (often paired with glucose oxidase/lactoferrin) where effective use levels in leave-on and rinse-off products are commonly in the ~0.0001–0.02% range for the active enzyme due to potency and stability constraints. At the low end, it appears in sensitive-skin creams/lotions and cleansers at trace levels to support microbiological control without adding traditional preservatives. The upper end reflects high-strength, consumer-available enzyme complex formulations and specialty deodorant/body-care products where lactoperoxidase can be present up to ~0.1–0.2% (typically as part of a broader enzyme blend), above which stability, cost, and diminishing returns generally limit use in OTC cosmetics.