Head to head
Nº.4 Bond Maintenance Strengthening Shampoo vs Acidic Bonding Concentrate Shampoo
Redken Acidic Bonding Concentrate Shampoo edges out Olaplex Nº.4 Bond Maintenance Strengthening Shampoo, 7.7 to 7.6. It wins on results, value and community love, while the Nº.4 Bond Maintenance Strengthening Shampoo is stronger on formula and texture and feel.
Benefit fingerprints
What each one does.
Olaplex Nº.4 Bond Maintenance Strengthening Shampoo
Redken Acidic Bonding Concentrate Shampoo
Side by side
Every detail, compared.
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Redken
Acidic Bonding Concentrate Shampoo
Highest score- Damage repair
- Split ends
- Frizz control
- Shine
- Damage repair
- Split ends
- Smoothing
- Color protection
- • Bleached, colored or chemically treated hair
- • Medium to coarse hair that needs softness and shine
- • Anyone already using the Olaplex bond treatments
- • Bleached, highlighted or color-treated hair
- • Anyone building a full Redken Acidic Bonding routine
- Sulfate-free, color-safe cleanse built around Olaplex's patented bond-building ingredient
- Reviewers report softer, shinier and less frizzy hair, especially on bleached or colored lengths
- Concentrated formula; brand says 250 ml lasts up to 100 washes
- Sulfate-free, acidic-pH formula aimed at damaged and color-treated hair
- Reviewers report softer, smoother and shinier lengths after bleach or color
- Refill and liter sizes lower the cost per wash
- $34 for 250 ml is expensive for a daily shampoo
- Some users find it too gentle for oily scalps or heavy product buildup
- Headline breakage and split-end claims rely on using several products from the line
- $37 for 300 ml is expensive for a daily shampoo
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Affiliate links — we may earn a commission. How we make money
FAQ
Quick answers.
Which is better, Nº.4 Bond Maintenance Strengthening Shampoo or Acidic Bonding Concentrate Shampoo?
Redken Acidic Bonding Concentrate Shampoo edges out Olaplex Nº.4 Bond Maintenance Strengthening Shampoo, 7.7 to 7.6. It wins on results, value and community love, while the Nº.4 Bond Maintenance Strengthening Shampoo is stronger on formula and texture and feel.
Which is better value?
Olaplex Nº.4 Bond Maintenance Strengthening Shampoo works out to about $4.02 / oz and Redken Acidic Bonding Concentrate Shampoo to about $3.65 / oz, based on typical non-Amazon retail prices when we last checked.
How do you score them?
Both are scored on the same five-factor rubric (results, formula & ingredients, texture & experience, value, community love), using the formula or specs, verified creator reviews, community consensus and value. Brands can’t pay for placement.