Nioxin Scalp + Hair System 4 Leave on Treatment 100ml

Why you'll love it

• Leave-on scalp and hair thickening treatment for coloured hair with progressed thinning
• Nourishes and strengthens each strand from root to tip
• Promotes the appearance of thicker, fuller hair
• UV-protecting ingredients for the scalp and hair
• Clinically and dermatologically tested, with visible results in 30 days*

The leave-on step that does the heavy lifting. Nioxin Scalp + Hair System 4 Leave-On Treatment 100ml is a leave-in thickening treatment, the serum step of the System 4 routine, designed for dry, damaged, colour-treated hair with progressed thinning. Clinically and dermatologically tested, it nourishes and strengthens each strand from root to tip for the appearance of thicker, fuller hair, while delivering UV-protecting ingredients to look after both scalp and hair.

As a leave-on treatment, it stays in the hair to keep working between washes, nourishing and strengthening each strand to help minimise breakage, which in turn helps hair look fuller and thicker (because less breaks off). It supports a healthier scalp environment too, and the UV-protecting ingredients help shield the scalp and hair, including helping to protect your colour. It's the targeted treatment step that makes the System 4 routine complete, and it can be bought on its own to top up or replace the treatment from your System 4 kit.

What it does for thinning, coloured hair

Dry, damaged, colour-treated hair with progressed thinning benefits from a leave-on treatment that keeps working all day. This serum nourishes and strengthens each strand from root to tip to reduce breakage and promote the appearance of fuller, thicker hair, while UV-protecting ingredients shield the scalp and hair. Used consistently as part of the System 4 routine, it's designed to deliver visibly thicker, fuller-looking hair over time.

How to use it

Apply the leave-on treatment to a clean, towel-dried scalp and hair, distributing evenly, and do not rinse out. Use as the treatment step of your System 4 routine, after cleansing and conditioning, for consistent, leave-in results, the studies are based on 30 days of regular use. You'll find the rest of the System 4 range in our professional shampoo collection.

Who it's for

This treatment is specifically for dry, damaged, colour-treated hair with progressed thinning, the System 4 category. If your hair sits elsewhere (natural rather than coloured, or at a lighter stage of thinning), there's a different-numbered Nioxin system and treatment better matched to you. We've spent years helping clients in Codsall make the most of fine and thinning hair, and a leave-on treatment like this is one of the most targeted ways to support fuller, thicker-looking hair between salon visits.

Build your thickening routine

For the best results, use this treatment as the leave-on step alongside the matching System 4 cleanser and conditioner, and the wider Nioxin range. Have a browse through our full range of professional haircare products to complete your routine, or explore all the professional names we stock over on our shop by brand page.

Add the Nioxin Scalp + Hair System 4 Leave-On Treatment to your routine for visibly thicker, fuller-looking, protected hair. Free UK delivery on all orders.

*Based on consumer studies: 85% of consumers noticed a thickening effect, 80% noticed an increase in hair density, and 80% noticed an increase in hair fullness. Individual results may vary.