How often should I use it?

Once a week for damaged hair. More frequent use does not compound the benefit, and on finer hair repeated heavy use can leave it feeling limp.

Will it repair my split ends?

No. A split end is a mechanical separation of the hair shaft and the only remedy is cutting it. What this reduces is further breakage above the split.

Best for damaged hairMeasurable repair on bleached or heat-damaged hairTreatment100 mlMilky, rinse-out

Olaplex

No.3 Hair Perfector

Name: No.3 Hair Perfector
Brand: Olaplex
Price: 30 USD
Availability: InStock

The at-home bond treatment that made bleached hair survivable — the one Olaplex worth buying

4.4

$30

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Suits: All hair types
Targets: BreakageBleach damageSplit endsHeat damage
Key ingredients: Bis-aminopropyl diglycol dimaleate

No.3 Hair Perfector specifications
Active	Bis-aminopropyl diglycol dimaleate
Use	Weekly, on damp hair, before shampoo
Contact time	10 minutes minimum
Vegan	Yes
Cost per use	≈ $2.50

What it actually does

Bleach and heat break disulphide bonds inside the hair shaft. Those bonds are what give hair its structure, and once broken, no conditioner replaces them — a conditioner coats the outside and makes damaged hair feel better while it is on.

The active here reconnects those bonds. That is a specific, patented chemical action, and it is why Olaplex created a category rather than joining one.

It is a pre-shampoo treatment, not a conditioner

The single most common mistake. This goes on damp hair before you shampoo, not on clean hair at the end like a mask. Applied to soaking hair it is diluted; applied after conditioner it cannot reach the shaft.

What to expect

Timeframe	What changes
Use 1	Hair feels slightly stronger wet. Modest.
Weeks 2-4	Noticeably less breakage when combing.
Weeks 6-8	Ends hold together; less mid-shaft snapping.
Ongoing	Maintains. It does not reverse split ends — nothing does.

Where it disappoints

On undamaged hair it does almost nothing. If you do not bleach, colour or heat-style, you have no broken bonds to repair and you will not see the point.

It does not fix split ends. A split end is mechanical separation; the only fix is cutting it.

Ten minutes is the floor, not the target. Most people rush it and conclude the product does not work.

Against K18

K18 works in four minutes on a different mechanism (keratin peptide rather than disulphide bond) and many people find it does more per treatment. This costs a third as much per use and is far easier to buy. Both are legitimate; neither is a scam.

The verdict

Pros

A patented, published mechanism rather than an ingredient story
Genuine reduction in breakage within a month on damaged hair
About $2.50 per treatment
Vegan and cruelty-free

Cons

Does very little on hair that is not chemically or heat damaged
Ten-minute minimum that most people rush
Cannot repair split ends — nothing can
Fragranced, with no unscented option

No.3 Hair Perfector FAQs

No, and using it like one is the most common mistake. It goes on damp hair before shampooing, is left at least ten minutes, and is then washed out. Applied after conditioner it cannot reach the hair shaft and does nothing.