Nioxin Diameter System 4 Scalp & Hair Treatment (Colored Hair, Progressed Thinning, Color Safe) 200ml

Nioxin Diameter System 4 Scalp & Hair Treatment is engineered for colored hair with progressed thinning, delivering targeted scalp care while helping hair appear thicker and fuller. As Step 3 in the 3D Care System Kit 4, this leave-in treatment is formulated to protect treated hair while you address thinning concerns, giving you a breathable, manageable routine without sacrificing color integrity.

Why this matters for color-treated hair—a specialized color-safe formula respects dyed strands while delivering scalp-focused benefits. The product uses Scalp Access Delivery 2.0 with UV-protection ingredients to shield treated hair from daily environmental stressors, helping preserve vibrancy while supporting a resilient hair fiber.

Key benefits that set Diameter System 4 apart

• Thicker, fuller-looking hair through enhanced scalp health and improved hair resilience, giving the appearance of more volume where thinning is most evident.
• Color-safe protection designed to respect dyed hair, maintaining color depth and shine without dulling or color fading.
• Moisture balance to keep scalp comfortable and reduce dryness that can accompany thinning, supporting supple, flexible hair.
• UV-protected formula helps guard color-treated strands from sun exposure and environmental stressors that can degrade color over time.
• Leave-in, no-rinse convenience fits into busy routines, so you can apply and go without washing out product.
• Part of a complete system complements Step 1 and Step 2 in the 3D Care System Kit 4 for a cohesive approach to thinning hair on color-treated scalps.
• Size comes in a 200 ml bottle, designed for regular use as part of your hair-thinning management routine.

Who is this product ideal for?

If you have colored or highlighted hair and are experiencing progressed thinning, Diameter System 4 is crafted for you. It’s especially suited for those who want a color-safe, scalp-focused treatment that supports a fuller look without compromising dye integrity. Ideal for daily use as the final step in a multi-part care routine that targets both scalp health and hair appearance.

How it works

The formula leverages advanced delivery technology (Scalp Access Delivery 2.0) with UV-protection ingredients to reach the scalp effectively while safeguarding color-treated hair. By maintaining moisture balance and strengthening the hair shaft, it contributes to a thicker, more resilient feel from root to tip, helping create a visibly fuller appearance over time.

How to use

Shake well before use. Apply evenly to the entire scalp. There’s no need to rinse, so you can continue with styling as usual after application. For best results, incorporate this step as part of your regular routine after washing and conditioning, consistent with the 3D Care System Kit 4 protocol.

Experience a thoughtful, color-conscious approach to thinning hair with Nioxin Diameter System 4. It’s designed to support scalp health, balance moisture, and deliver a noticeable, natural-looking fullness—without compromising the color you love.