Nioxin System 4 Liter Duo
Includes:
- System 4 Cleanser 33.8 oz
- System 4 Scalp Therapy 33.8 oz
System 4 delivers denser-looking hair and restores moisture balance. System 4 is specially designed for noticeably thinning, fine, chemically-treated hair. It delivers denser-looking hair while protecting the scalp and providing moisture balance to colored hair.
| Product | Size | Key Benefit |
|---|---|---|
| System 4 Cleanser | 33.8 oz | Removes buildup and cleanses without stripping moisture |
| System 4 Scalp Therapy | 33.8 oz | Supports scalp health and enhances hair density |
FAQ
How does System 4 help with fine or chemically-treated hair?
System 4 is formulated to address thinning and fine hair by improving hair density and moisture balance. It is especially effective for chemically-treated hair, helping to preserve color and reduce damage.
Can I use System 4 with other hair care products?
Yes, System 4 can be used as part of a regular hair care routine. It works well with other products designed for color-treated or sensitive scalps.
Is the System 4 duo suitable for daily use?
Yes, the System 4 duo is designed for daily use to maintain moisture balance and support hair density over time.

Ryan Vaughan –
After using the System 4 Duo for a month, my fine, color-treated hair feels much fuller and less brittle. The cleanser removes residue without drying out the strands, and the scalp therapy helps my hair look thicker. I notice a visible improvement in volume, especially after washing.
Natalie Peake –
I have thinning hair from frequent coloring, and this duo has made a noticeable difference. My hair feels softer and more manageable. The scalp therapy helps reduce itchiness, which I didn’t expect. Still, it takes a few weeks to see full results.
Nicholas Anderson –
The product works well for my chemically treated hair. I use the cleanser every other day and the scalp therapy once a week. My hair has become more voluminous and the color stays vibrant without fading quickly.