Olaplex N°.4 Bond Maintenance™ Hair Strengthening Shampoo: Repairs Damage & Defend Against Future Breakage | Replenishes…
Best for
Best overall
Amazon rating
Amazon aggregate, one input among many in the Verdict Score
Based on 1 trusted source
Current price
$34.00
Updated May 18, 2026 · 1 min read
Sources behind this verdict
10 reviewers weighted by source trust
The consensus
What reviewers found
Synthesized across the trust-weighted source mix below.
Across the reviewers we read, the consensus on Olaplex No. 4 is that it's the most-recommended bond-repair shampoo for chemically processed, bleached, or heat-damaged hair, and it largely earns that reputation. A byrdie.com write-up highlights the bond-building ingredient blend and the way it lathers despite being sulfate-free, and a high-trust r/HaircareScience thread contains an unusually emphatic endorsement calling it the best shampoo that commenter has ever used.
What reviewers liked
- High-trust specialist community (r/HaircareScience) includes strong endorsements for damaged hair
- Verified-tier coverage on byrdie.com highlights effective bond-building chemistry and good lather despite being sulfate-free
- Very large Amazon review base (78k+) at a 4.6 average suggests broad real-world satisfaction
- Color-safe and works across hair textures per multiple retailer reviews
Where it falls short
- Reviewers with fine hair on r/Sephora and r/finethinhair report it feels too heavy or causes protein buildup over time
- At $34 it's one of the priciest shampoos in this roundup
- Several user reports tie extended use to increased breakage, though causation is contested
- Likely overkill for anyone whose hair isn't color-treated, bleached, or heat-damaged
Across the reviewers we read, the consensus on Olaplex No. 4 is that it's the most-recommended bond-repair shampoo for chemically processed, bleached, or heat-damaged hair, and it largely earns that reputation. A byrdie.com write-up highlights the bond-building ingredient blend and the way it lathers despite being sulfate-free, and a high-trust r/HaircareScience thread contains an unusually emphatic endorsement calling it the best shampoo that commenter has ever used. The 4.6-star average across more than 78,000 Amazon reviews lines up with that read.
The disagreement is meaningful and worth flagging. r/Sephora commenters with finer or less-damaged hair describe the formula as too rich and even greasy, and an r/finethinhair thread surfaces concerns about protein overload with extended use. Reddit threads on r/UsefulThingsOnly and r/IndianSkincareAddicts strike a more measured tone, calling it good but not miraculous. The pattern across reviewers is consistent: the more damaged your hair, the better No. 4 performs; the finer and healthier your hair, the more likely you are to find it overkill at $34.
- A highly concentrated, color-safe shampoo proven to reduce breakage and nourish hair leaving it smoother, shinier, and more manageable with every wash.
- KEY BENEFITS ✓ Reduces breakage and strengthens hair ✓ Gently cleanses without stripping moisture ✓ Hydrates, smooths, nourishes, and detangles
- Clinically Proven 90% smoother, better detangling, more conditioned* 49% reduction in breakage *When used as a system of Nº 3, Nº 4, and Nº 5.
- INGREDIENTS Gentle Blend of Coconut Oil-Derived Surfactants Provides an easy, abundant lather that leaves the scalp and hair feeling hydrated.
Straight out of the bottle: Smells clean and salon-ish. Not overpowering. · While washing: Shampoo lathers well, even though it's sulphate-free.
It is not a magic cure, but I think the conditioner has done a great job. It feels slightly softer and smoother than my previous conditioner ( ...
Trust tier reflects our editorial assessment of the source, not the individual quote. Hover for the rationale. See how we tier sources →
“Olaplex No. 4 & No. 5 First Impressions” · YouTube
If the consensus convinced you
Check current price on Amazon
Pricing and availability change frequently. Tap through to confirm before buying.