Redken Acidic Grow Scalp & Hair Serum 3.4 fl oz — Lightweight leave-in for rebalanced scalp and visible volume

Redken Acidic Grow Full System Scalp & Hair Serum is a lightweight leave-in treatment that rebalances scalp pH, delivers moisture, and gives the appearance of fuller, thicker hair.

This concentrated 3.4 fl oz serum is part of Redken's Acidic Grow Full System. Formulated with a 5% Strength Complex including azelaic acid, it’s designed to soothe and hydrate the scalp while creating instant root lift and visible density when used alongside the matching shampoo, conditioner, and densifying spray. The non-greasy texture works on both dry and damp scalps and was evaluated in consumer testing that included GLP-1 users.

How does this serum rebalance scalp pH and why does that matter?

The formula contains acidic actives that help restore a balanced scalp environment, supporting natural moisture levels and reducing the appearance of dryness. A rebalanced scalp can improve how hair sits at the root, creating better-looking volume without heavy styling products.

• Contains a 5% Strength Complex with azelaic acid for targeted scalp care
• Lightweight, non-greasy base avoids weighing hair down
• Designed to be leave-in for continuous pH support between washes

Will this serum make hair actually thicker or just look thicker?

The product is a cosmetic leave-in treatment formulated to create fuller, thicker-looking hair immediately through moisture, root lift, and texture. Consumer testing reported increased perception of thickness when the serum was used with the full Acidic Grow system.

• Instant root lift for visible volume at the scalp
• Hydration and texture that increase hair body
• Best results when paired with the complete Acidic Grow regimen

How should I apply the Redken scalp & hair serum for best results?

Apply a few drops directly to a dry or towel-dried scalp, focusing on areas where lift or hydration is needed. Gently massage to distribute the formula; leave in—no rinsing—then style as usual. Use daily or as directed for ongoing scalp comfort and visual density.

• Works on clean, damp hair or on dry scalp for touch-ups
• Small quantity spreads well—start light and add as needed
• Combine with Acidic Grow shampoo, conditioner, and spray for system results

Is this serum suitable for people using GLP-1 medications?

Redken’s Acidic Grow line was evaluated in consumer testing that included GLP-1 users, who reported positive cosmetic benefits. The serum is a topical, cosmetic product and does not interact with medications; consult a healthcare provider for medical advice.

• Included in consumer tests with GLP-1 users
• Topical, non-prescription cosmetic formulation
• Designed to support scalp comfort and visual density

Who is this for: The Redken Acidic Grow Full System Scalp & Hair Serum is made for anyone wanting a lightweight, leave-in scalp treatment that adds moisture, restores balance, and increases visible hair fullness. It’s especially useful for people noticing reduced density or scalp dryness and for those who prefer non-greasy daily products. For optimal effect, use it as part of the full Acidic Grow system (shampoo, conditioner, serum, and instant densifying spray).