What ingredients should I avoid in a serum used with LED light therapy attachments?

Avoid photoactive or photolabile ingredients such as retinol, benzoyl peroxide, and certain vitamin C derivatives (L-ascorbic acid) in formulas applied immediately before LED sessions, as red and infrared light can degrade them or cause unintended skin reactions. Stable antioxidants like vitamin C derivatives (ascorbyl glucoside) and peptides are safer pairings. Consult a cosmetic chemist via the AJ Cosmo Labs iPhone app for formula-specific guidance.