iS Clinical treatment products represent the most active step in the Cleanse, Treat, Hydrate, Protect regimen — delivering pharmaceutical-grade serums, eye care, and targeted formulations that address specific skin concerns at clinically effective concentrations. The Treat step is where visible transformation happens, with concentrated actives designed to support the appearance of smoother, firmer, and more radiant-looking skin.

Serums form the core of the Treat step. Active Serum is the brand's most versatile treatment, combining botanically derived acids with potent antioxidants to visibly refine texture and support a clearer-looking complexion. For advanced anti-aging support, Super Serum Advance+ delivers plant-derived growth factor analog that support the appearance of firmer, smoother-looking skin. Pro-Heal Serum Advance+ provides pharmaceutical-grade Vitamin C with Olive Leaf Extract for antioxidant support and calming benefits.

Additional treatment options include Hydra-Cool Serum for lightweight hydration with Hyaluronic Acid, Brightening Serum for targeting the appearance of uneven tone, and Retinol+ Emulsion 0.3 for stabilized retinoid renewal. Eye-specific treatments like C Eye Serum Advance+ and exfoliating treatments like Tri-Active Exfoliating Masque also belong in this step.

Apply treatment products after cleansing and before moisturizer for optimal absorption. Layer lighter serums first, followed by richer formulations. Trusted by professionals in 60+ countries.

Explore specific treatment categories: serums, eye care, or exfoliants. Discover your ideal regimen with the skincare recommendation quiz.