NIOXIN System 4 Scalp + Hair Thickening Treatment — 3.4 fl oz for Color‑Treated, Damaged Hair | Lightweight Leave‑In Serum to Boos

Nioxin System 4 Scalp + Hair Thickening Treatment is a leave-in serum formulated to nourish the scalp and visibly increase hair thickness for color-treated, damaged hair with progressed thinning.

This lightweight 3.4 fl oz treatment completes Nioxin's three-step System 4 regimen. It delivers targeted nutrients, antioxidants and botanical extracts to the scalp while reinforcing each strand to reduce breakage and improve the appearance of density. Designed specifically for color-treated, dry or damaged hair experiencing advanced thinning, the formula supports a cleaner, healthier scalp environment so hair looks fuller and stronger over time.

How does this treatment support scalp health?

The formula is built to refresh the scalp by removing residue and supplying nourishment where follicles meet the skin. A balanced scalp environment helps hair fibers remain stronger and less prone to breakage.

• Scalp Access Delivery System 2.0 helps deposit nutrients at the scalp surface.
• Antioxidants and botanicals protect scalp skin from environmental stressors.
• Lightweight, non-greasy leave-in texture avoids weighing hair down.

Will it visibly thicken and add fullness to color-treated hair?

System 4 is clinically designed for color-treated hair with progressed thinning to increase apparent diameter and fullness. Many users notice improved density and a thicker look with consistent use.

• Targets strand structure to amplify hair diameter.
• Helps reduce hair breakage that contributes to thinner-looking hair.
• Formulated to preserve hair color while improving body.

How should I use the treatment for best results?

Use the Scalp + Hair Thickening Treatment as the finishing step after cleansing and conditioning with Nioxin System 4 products. Apply directly to the scalp, massage gently, and style as usual; it is a leave-in product so no rinsing is required.

• Apply daily to a towel-dried or dry scalp for targeted coverage.
• Part hair into sections to ensure product reaches the scalp.
• Massage lightly to encourage even distribution and absorption.

What measurable benefits can I expect and when?

Results vary by individual, but System 4 is formulated to deliver visible improvement in fullness and thickness with regular use. Clinical assessments and consumer feedback indicate perceptible changes within weeks of consistent application.

• Noticeable increase in fullness and density reported by many users.
• Strengthens strands to lessen breakage that contributes to thinning appearance.
• Helps maintain scalp cleanliness and resilience over time.

Who is this for: Nioxin System 4 Scalp + Hair Thickening Treatment is intended for people with color-treated, dry or damaged hair experiencing progressed thinning who want a leave-in serum to fortify strands, improve scalp condition and create the look of fuller hair. It pairs with the System 4 shampoo and conditioner as the final step in a targeted regimen for strengthened, more voluminous hair appearance.

Ingredients

Aqua, Phenylbenzimidazole Sulfonic Acid, Niacinamide, Benzophenone-4, Caffeine, Polysorbate 20, Sodium Hydroxide, Benzyl Alcohol, Sodium Benzoate, Phenoxyethanol, PEG-12 Dimethicone, Citric Acid, Cocamidopropyl Betaine, Acetamide MEA, Isopropyl C12-15-Pareth-9 Carboxylate, Tetrasodium EDTA, Propylene Glycol, Methyl Nicotinate, Sodium Chloride, Parfum, Polysorbate 60, Polysorbate 80, Mentha Piperita Oil, Mentha Arvensis Leaf Oil, Menthol, PEG-23M, Camellia Sinensis Leaf Extract, Limonene, Cystine Bis-PG-Propyl Silanetriol, Biotin, Lecithin, Tocopheryl Acetate, Foeniculum Vulgare Fruit Extract, Silica, Faex Extract, Acer Saccharum Extract, Citrus Limon Peel Extract, Saccharum Officinarum Extract, Vaccinium Myrtillus Leaf Extract, Citrus Aurantium Dulcis Fruit Extract, Potassium Sorbate