Redken Acidic Grow Full System Scalp & Hair Serum 3.4 oz — Lightweight Leave-In with 5% Azelaic Acid for Root Lift & Fuller-Lookin

Redken Acidic Grow Full System Scalp & Hair Serum is a lightweight leave-in treatment that rebalances scalp pH, hydrates, and helps hair look fuller and thicker.

This serum is part of Redken's Acidic Grow Full System and uses a 5% Strength Complex including azelaic acid to support a more balanced scalp environment. Formulated to be non-greasy and suitable for daily application, it can be used on dry or damp hair and is designed to deliver instant root lift and improved-looking density when paired with the complete system.

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

The formula includes acidic actives that help restore the scalp's natural pH balance, creating conditions that support healthier-feeling skin at the roots. Maintaining the right pH helps the scalp retain moisture and can reduce the appearance of imbalance-related issues.

• Contains azelaic-acid–infused 5% Strength Complex to target scalp environment.
• Leave-in application preserves pH impact between washes.
• Suitable for daily use on dry or damp scalp to maintain balance.

Will this make my hair look thicker right away?

You can expect an immediate visual boost in root lift and fuller-looking hair when you use the serum as part of the Acidic Grow Full System (shampoo, conditioner, serum, and spray). The lightweight texture lifts at the roots without weighing hair down, producing an instant denser appearance.

• Instant root lift and fuller appearance with system use.
• Non-greasy formula that doesn’t leave residue or dullness.
• Works best combined with Redken’s coordinating shampoo, conditioner, and spray.

How should I use this leave-in serum for best results?

Dispense the serum directly to the scalp and gently massage or distribute through the roots; it can be applied to dry or towel-dried hair. For optimal outcome, incorporate it into the complete Acidic Grow Full System and follow the recommended routine frequency on the packaging.

• Apply to clean, dry or damp scalp; no rinsing required.
• Massage into scalp to ensure even coverage at the roots.
• Combine daily use with the shampoo, conditioner, and instant densifying spray.

Is this product suitable for people experiencing medication-related hair changes?

This serum has been evaluated with participants using GLP-1 therapies and showed positive consumer responses when used as part of the full Acidic Grow routine. While individual results vary, many users reported thicker-feeling hair in system testing scenarios.

• Tested in consumer groups that included GLP-1 users.
• Designed to support scalp moisture and immediate visual density.
• Safe for routine use as part of a broader haircare regimen.

Who this is for: This Redken Acidic Grow Full System Scalp & Hair Serum is aimed at anyone seeking a lightweight, leave-in solution to improve scalp balance and boost the visual density of thinning or fine hair. It’s particularly useful for people who want a non-greasy daily treatment that pairs with a complete system of shampoo, conditioner, and densifying spray to maximize immediate root lift and fuller-looking hair.