Thin, flat, won't-hold-a-thing hair has met its match. This is the lightweight leave-in scalp serum that treats fullness as an inside job — starting at the roots, where thicker-looking hair actually begins.
TL;DR: The Redken Acidic Grow Full System Scalp & Hair Serum is a lightweight, pH-balanced, leave-in treatment for fine, flat and thinning hair. Powered by azelaic acid, caffeine and prebiotics, it rebalances the scalp, adds moisture and helps promote denser, thicker-looking hair — no rinsing, no residue, no weigh-down.
Product Details and Benefits
- Made for thin, flat and fine hair — a densifying leave-in for anyone chasing more body at the root and along the lengths.
- Azelaic acid + 5% Strength Complex — azelaic acid rebalances the scalp's naturally acidic pH, while the 5% Strength Complex is formulated to reinforce the hair fibre.
- Caffeine and prebiotics — a targeted blend that supports a healthy-looking, comfortable scalp: the real foundation for fuller-looking hair.
- Promotes denser, thicker-looking hair — adds moisture and visible density without a greasy after-feel.
- Part of the Acidic Grow Full System — pair it with the matching shampoo, conditioner and densifying spray for the fullness of +5,000 hair fibres.*
- Lightweight and non-greasy — a fast-absorbing leave-in that leaves no residue and won't drag fine hair down.
- Warm citrus fragrance — a fresh, salty-citrus scent with a whisper of neroli.
- Vegan and never tested on animals — salon-professional care that behaves itself.
How to Use
- Start with clean, towel-dried hair (dry hair is fine too — this serum isn't fussy).
- Spray directly onto the scalp and roots, holding the nozzle a short distance away, about 1 to 2 cm.
- Massage in with your fingertips. Don't rinse — leave it to work and style as usual.
- Use daily for best results.
Pro tip: Section your hair like you're prepping for a colour service — a few clean parts across the scalp — before you spray. It feels overly precise, but it lands the serum on scalp skin rather than the mid-lengths, which is exactly where azelaic acid does its pH-rebalancing work.
Why You'll Love It
Fuller-looking hair shouldn't require a maths degree or a shelf full of bottles — just one clever leave-in that starts where volume actually begins. Add the Redken Acidic Grow Full System Serum to your cart and give thin, flat hair the root-level rethink it's been waiting for.
The fullness of +5,000 hair fibres is based on use of the complete Acidic Grow Full System (shampoo, conditioner, serum and spray). Source: redken.com.
