Redken Densifying Shampoo Acidic Grow 33.8 fl oz — Lightweight, Scalp‑Friendly Volume

Redken Acidic Grow Full System Densifying Shampoo is a lightweight, scalp-friendly cleanser designed to make thin or thinning hair look fuller and thicker when used as part of the Acidic Grow Full System.

This shampoo combines a 7% Densifying Complex and scalp-conditioning ingredients in a gentle, acidic formula created for fine, flat, or thinning hair. The 33.8 fl oz bottle provides a salon-sized supply that cleanses without stripping natural oils, helps rebalance the scalp, and supports instant volumizing effects when paired with the matching conditioner, serum, and spray. It’s also formulated to be safe on color-treated hair and was evaluated with GLP-1 users experiencing hair changes.

How does this shampoo improve the appearance of thin or thinning hair?

The formula focuses on density-building and scalp health rather than heavy-weight smoothing. Lightweight cleansing agents remove residue while the 7% Densifying Complex creates a plumping visual effect at the hair fiber base, helping hair look thicker right away when used with the full system.

• 7% Densifying Complex to support fuller-looking strands
• Instant volumizing effect when combined with conditioner, serum, and spray
• Non-stripping, acidic pH to preserve the scalp barrier

Will this shampoo be gentle on my scalp and color-treated hair?

Yes—its lightweight, acidic formulation is designed to cleanse while maintaining the scalp’s natural protective layer and minimizing color fade. The product aims to rebalance and moisturize the scalp, making it suitable for daily or frequent use depending on personal needs.

• Acidic pH supports scalp barrier health
• Formulated to be safe for color-treated hair
• Moisturizing components help reduce dryness and irritation

How should I use the Acidic Grow Full System Shampoo for best results?

For optimal visual density and scalp benefits, use the shampoo as the first step in the Acidic Grow Full System: follow with the matching conditioner, apply the scalp & hair serum, and finish with the instant densifying spray. Lather, rinse, and repeat if hair is especially oily or product-laden.

• Apply to wet hair, massage into the scalp, and rinse thoroughly
• Follow with Acidic Grow Full System Conditioner for added volume
• Use serum and instant densifying spray as directed for cumulative benefits

What evidence supports this shampoo’s performance?

Consumer testing that included GLP-1 users reported that most participants perceived thicker-feeling hair when using the entire Acidic Grow system. While individual outcomes vary, combining all four system steps—shampoo, conditioner, serum, and spray—produced the most consistent results in user trials.

• Consumer-tested with GLP-1 users experiencing hair changes
• Reported increase in perceived thickness when using the four-product system
• Designed to deliver instant volumizing appearance

Who is this for: Redken Acidic Grow Full System Densifying Shampoo is intended for people with fine, flat, or thinning hair who want a lightweight cleanser that prioritizes scalp balance and visual fullness. It’s a good option for those who color their hair, are noticing reduced volume, or are using GLP-1 medications and seek a non-irritating, salon-grade product to help hair look fuller when used as part of the full Acidic Grow routine.

Ingredients

AQUA / WATER / EAU, SODIUM LAURETH SULFATE, COCAMIDOPROPYL BETAINE, SODIUM CHLORIDE, PROPYLENE GLYCOL, PARFUM / FRAGRANCE, CITRIC ACID, COCAMIDE MEA, SODIUM BENZOATE, SODIUM HYDROXIDE, HEXYLENE GLYCOL, BIFIDA FERMENT LYSATE, SACCHAROMYCES/RICE FERMENT FILTRATE, SODIUM LAURYL SULFATE, HYDROXYPROPYL GUAR HYDROXYPROPYLTRIMONIUM CHLORIDE, CAFFEINE, AZELAIC ACID, LINALYL ACETATE, CARVONE, PENTYLENE GLYCOL, LINALOOL, LIMONENE, CITRUS LIMON PEEL OIL, CITRUS AURANTIUM BERGAMIA PEEL OIL, CITRAL, CITRUS AURANTIUM PEEL OIL, PINENE, PHENOXYETHANOL, SALICYLIC ACID