Neutralizes brassiness for brighter hair.
This is a marketing claim; an ingredient list cannot speak to it.
—
Stated by brand
Can’t be confirmed from label.
Olaplex · Blonde Enhancer
Nº.4P Blonde Enhancer Toning Shampoo
Shampoo / Clarifying, deep-cleaning
- Shampoo
- Sulfate-free
- Silicone-free
- Protein-free
Size8.5 fl oz (250 ml)usual store size · 2 sizes
Price$30seen at one store · 8.5 oz · from $2.84/oz in the 33.81 oz
Price / oz$3.65/ozat 8.5 oz
Where to buy3 stores · 2 sizes
Add it to your products. We’ll tell you if it’s ever recalled.
Scent:
The ingredient list declares fragrance. What it smells of is not stated, and we do not guess.
Manufacturer page: olaplex.com
Personal fit
Is this right for you?
Complete the consultation to see how well this product fits your hair and your goals. With 6,000+ products in our library, we can match you to the right ones.
- About 20 minutes, and your answers save as you go.
- Every product matched against your hair across the 22 factors we check.
- A personalized routine built around your schedule, styling habits, and local weather.
- Find products that do the same job at a lower cost.
- Your goals, scalp, damage history, water, budget, and scent preferences all shape your plan.
$49 with 60 days of follow-up questions and plan updates
$99 with 12 months. Pay once; the year renews only if you choose.
Factor
Your profile
Fit
Best for hair types
All types
Not in your profile
Moisture level
High
Not in your profile
Cleansing strength
Strong
Not in your profile
Slip / detangling
Moderate
Not in your profile
Weight on hair
Light
Not in your profile
Fragrance
Present
Not in your profile
Protein
None
Not in your profile
Silicone / wax buildup
None
Not in your profile
Clarifying wash needed
Low
Not in your profile
Sulfates
None listed
Not in your profile
Show all 22 factors we check
The rest of what your plan weighs on this product.
Parabens / preservatives
None of these listed
Not in your profile
Essential oils
Present
Not in your profile
Fast-drying alcohol
None
Not in your profile
Vegan / cruelty-free
Not yet verified
Not in your profile
Animal-derived ingredients
Not yet verified
Not in your profile
Heavy humectants
Heavy
Not in your profile
Hard-water defence
None
Not in your profile
UV filter
None listed
Not in your profile
pH adjusted
Adjusted
Not in your profile
Ingredient list
23 ingredientsAbout average
Not in your profile
Price tier
Prestige
Not in your profile
Where to buy it
ManufacturerOne channel
Not in your profile
The consultation builds your hair profile, checks every factor in this table against it, and tells you where this product fits or what to use instead.
Start your consultation$49 once, with 60 days of follow-up questions and plan updates. Nothing renews, and you never have to buy a product.
Your avoid-list
Same job for less elsewhere
$3.65/oz at 8.5 oz, more than 81% of the 1544 shampoos , which mostly run $0.79–3.04/oz.
Great for
Colour-treated hairthat fades faster in a sulfate wash
Protein-sensitive hairthat stiffens when protein is added
Fast-oiling scalpsthat need a real reset wash
Curly-method routinesno sulfates and no water-insoluble silicones
Fine hairthat flattens under most products
Silicone-free routinesno silicones appear in the list
Maybe skip if
this product has a scent
Dry or damaged haira strong detergent system strips as it cleans
Hair that needs proteinthere is none in this list
Dry or very humid airwhere heavy humectants work against you
Hard waterno chelator here to bind the minerals
Tight budgetsit sits in the upper price tiers
What the formula actually does
Read from the label, not the marketing
Each row says where it comes from: F means we derived it from this product’s own ingredient list, S means it is a claim the brand makes that the formula neither confirms nor contradicts.
Cleansing strength
Strong
A reset wash that removes oil, buildup, and most residue.
Expected lather
High
Thick foam that spreads quickly through the hair.
Slip and detangling
Moderate
Conditioning agents are present, lower in the list.
Water-binding (humectants)
High
Humectants near the top: binding water is one of its main jobs.
Scalp active
None
No over-the-counter scalp active.
Hard-water defence
None
No chelating agent in the list.
Needs detergent to remove
No
Nothing here needs a detergent wash to remove.
Protein
None
No protein or amino acids in the list.
Fragrance
Present
Fragrance is listed; it sits below the working ingredients.
from the formula
stated by the brand
reported by reviewers
Scale: 1 dot low · 5 dots high, within this product type.
Ingredients that matter
The ingredients that change a decision
The workhorse ingredients, plus anything lower down that changes a decision. The chips name what an ingredient does. They are not safety scores, and no ingredient here is rated good or bad on its own.
| Ingredient | What it does | Why it matters | Chip |
|---|---|---|---|
| WaterAqua (Water, Eau) | solvent | The base everything else is dissolved in | Neutral |
| Sodium C14-16 Olefin Sulfonate | olefin sulfonate cleanser | — | Cleanses |
| Cocamidopropyl Betaine | amphoteric cleanser | — | Cleanses |
| Glycerin | humectant | Pulls water into the hair | Moisturizes |
| Sodium Chloride | salt | Thickens the formula | Stabilizes |
| Sodium Cocoamphoacetate | amphoteric cleanser | — | Cleanses |
| Acrylates Copolymer | film former | Lays down the film that holds a shape | Holds |
| Bis-Aminopropyl Diglycol Dimaleate | conditioning agent | Reduces combing force | Detangles |
| FragranceParfum (Fragrance) | fragrance | The scent | Fragrance |
| Menthol | fragrance | The scent | Fragrance |
| Citrus Aurantium Peel Oil | botanical extract | A trace plant extract | Fragrance |
| Limonene | fragrance | The scent | Fragrance |
What the list leaves out, and what it carriesThe list carries no sulfates, silicones, or drying alcohols. No protein: a moisture formula, not a repair one. Fragrance is on the label.
Full ingredient list (23)
In the US, ingredients above 1% are listed from most to least. Below 1% they can appear in any order. Each note keeps three things apart: what the ingredient generally does, its role in this type of product, and what its position can tell you.
-
1
Water
· Aqua (Water, Eau)
General function
The base of almost every rinse-off and cream hair product. It carries everything else and is normally the first ingredient on the label.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
- solvent
-
2
Sodium C14-16 Olefin Sulfonate
General function
A strong non-sulfate detergent used in "sulfate-free" shampoos. It cleans about as thoroughly as a sulfate despite the label difference.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
PubChemMay suitBuild-up-sensitive routinesA strong detergent with no sulfate on the label. It removes deposited films about as completely as a sulfate does.
May not suitVery dry or highly damaged hairSulfate-free on the label is a naming fact, not a mildness one: this is an efficient detergent, and hair short of moisture can feel it.
- olefin sulfonate cleanser
- cleanser
-
3
Cocamidopropyl Betaine
General function
A mild coconut-derived co-cleanser that boosts foam and softens the effect of stronger detergents. It appears in most shampoos, gentle or not.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
Indian Journal of DermatologyMay suitDry, coarse, or high-porosity hairMild cleansing leaves more surface lubrication in place on hair that dries out quickly.
May not suitBuild-up-sensitive routinesThe mildest detergents are also the least complete: a routine that deposits films needs something stronger periodically.
DependsVery dry or highly damaged hairAmong the mildest detergents in use — it is what baby shampoos are built on — but it is almost always the second detergent in a formula. How much a wash strips is still decided by the primary detergent listed above it.
- amphoteric cleanser
- secondary cleanser
- cleanser
-
4
Glycerin
General function
Glycerin, also called glycerol, attracts moisture and mixes completely with water.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
Scientific ReportsMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairWater moves both ways. Measured across concentrations, glycerin solutions give water up in some conditions and take it from the air in others. What it does for you depends on how much of it is there and on the air around it.
- humectant
-
5
Sodium Chloride
General function
Table salt. In shampoo it is used to thicken the liquid, not to treat the hair.
Supporting ingredientPubChemListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
- salt
- thickener
-
6
Sodium Cocoamphoacetate
General function
A very mild cleanser common in baby and sensitive-scalp shampoos.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
May suitDry, coarse, or high-porosity hairMild cleansing leaves more surface lubrication in place on hair that dries out quickly.
May suitVery dry or highly damaged hairOne of the mildest detergent classes. It is usually there to let a formula lather without a harsher detergent doing the work.
May not suitBuild-up-sensitive routinesThe mildest detergents are also the least complete: a routine that deposits films needs something stronger periodically.
- amphoteric cleanser
- secondary cleanser
- cleanser
-
7
Acrylates Copolymer
General function
A hold polymer that forms a firm, humidity-resistant film. It is the usual source of a hard cast in gels.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
May suitClimate-sensitive or frizz-prone hairA set polymer film is a physical barrier to humidity, so a style keeps its shape longer in damp conditions.
May suitMaximum-hold stylingSynthetic film formers dry into a continuous film, which is what holds a shape against movement and against humid air.
DependsBuild-up-sensitive routinesSome acrylate copolymers rinse with water and some need a detergent; the label alone does not say which one a formula used.
- film former
- polymer
-
8
Bis-Aminopropyl Diglycol Dimaleate
General function
A bond-repair ingredient that reacts with sulfur groups in the hair. It is the active in one of the widely marketed bond-building systems.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
May suitFrizz-prone, damaged, or high-friction hairDeposits a lubricating layer that makes combing easier, which is most of what stops mechanical damage adding to frizz.
- conditioning agent
-
9
Betaine
General function
A sugar-beet derived humectant that binds water. Despite the name it is not a cleanser like cocamidopropyl betaine.
Secondary ingredientLower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.
PubChemMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairA humectant moves water in whichever direction the air allows: it holds moisture in humid conditions and can pull it back out of hair in very dry ones.
- humectant
-
10
Polyquaternium-7
General function
A conditioning polymer that improves wet combing and adds body. Repeated use can build up on fine hair.
Secondary ingredientLower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.
May suitCurls or waves needing flexible holdCationic polymers hold a curl loosely and stay soft, which is why they turn up in definition products rather than firm-hold ones.
May suitFrizz-prone, damaged, or high-friction hairA cationic polymer stays on the hair through rinsing, which is what keeps static and combing friction down after the wash.
May suitMaximum-hold stylingFilm formers are what hold a style: they dry into a connected film across the strands so the shape resists movement.
- conditioning agent
- film former
- polymer
-
11
Guar Hydroxypropyltrimonium Chloride
General function
A conditioning polymer made from guar bean gum. It deposits during rinsing, which is why sulfate shampoos can still leave hair soft.
Secondary ingredientLower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.
May suitCurls or waves needing flexible holdGums thicken and set soft, which gives definition that bends rather than a rigid cast.
May suitFrizz-prone, damaged, or high-friction hairCationic conditioners bind to the negatively charged damaged cuticle, laying it flat and cutting the friction that causes combing breakage.
May suitMaximum-hold stylingA styling polymer dries into a film across the strands, which is what makes a shape hold instead of relax.
- conditioning agent
- polymer
- gum
- ▾Below about here, the order stops meaning much. These are usually used at 1% or less.
-
12
Ethylhexylglycerin
General function
A preservative booster that also adds a little softness. Almost always paired with phenoxyethanol.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitFrizz-prone, damaged, or high-friction hairEmollients fill and smooth the surface of the strand, which lowers the friction that lifts the cuticle and reads as roughness.
- preservative
- emollient
-
13
Fragrance
· Parfum (Fragrance)
General function
An undisclosed blend of scent ingredients. Regulations let it stay unlisted, so a fragrance-free product is the only way to be certain what is not in it.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
May not suitFragrance-sensitive routinesDeclared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.
- fragrance
- declared fragrance
-
14
Citric Acid
General function
Used to bring the product to a slightly acidic pH, which helps the cuticle lie flat. It is almost always near the end of the list.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
International Journal of TrichologyMay suitBuild-up-sensitive routinesHolds hard-water minerals in solution so they rinse away instead of depositing on the hair.
May suitFrizz-prone, damaged, or high-friction hairThe acid side of pH adjustment, and the reason it matters is measured: alkaline formulas raise the fibre's surface negative charge, increase friction between strands and lift the scales, while lower-pH ones do the reverse.
May suitGray, silver, or brass-prone hairWhere a warm cast comes from water minerals rather than from the hair itself, holding those metals in solution is what removes it.
- pH adjuster
- hard-water chelator
-
15
Phenoxyethanol
- preservative
-
16
Menthol
General function
Produces the cooling, tingling feeling on the scalp. The sensation is real; it is not evidence that anything else is happening.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay not suitFragrance-sensitive routinesDeclared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.
- fragrance
- active
-
17
Citrus Aurantium Peel Oil
General function
A cold-pressed orange peel oil used for scent. Citrus oils are naturally high in limonene.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
May not suitFragrance-sensitive routinesEssential oils are fragrance. Several carry constituents on the EU list of declared fragrance allergens, so a label with no fragrance line can still be a scented product.
- botanical extract
- essential oil
- fragrance
-
18
Limonene
General function
A citrus-smelling fragrance component that EU rules require to be named separately because some people react to it.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay not suitFragrance-sensitive routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
19
Hexyl Cinnamal
General function
A jasmine-like fragrance component named separately as a recognised allergen.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay not suitFragrance-sensitive routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
20
Sodium Benzoate
- preservative
-
21
Ci 60730 (Ext. Violet 2)
- colourant
- direct dye
- violet dye
-
22
Yellow 5
· CI 19140 (Yellow 5)
General function
A certified colour added to tint the product itself. It does not colour hair.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
May suitGray, silver, or brass-prone hairA violet or blue colorant sits opposite yellow on the colour wheel, so a trace of it deposited on the surface makes a warm cast read cooler. It washes out over the following few washes.
- colourant
-
23
Ci 15985 (Yellow 6)
General function
A certified colour that tints the product itself. It does not colour hair.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
May suitGray, silver, or brass-prone hairA violet or blue colorant sits opposite yellow on the colour wheel, so a trace of it deposited on the surface makes a warm cast read cooler. It washes out over the following few washes.
- colourant
What the whole list adds up to
- 5 fragrances
- 3 cleansers
- 3 polymers
- 3 preservatives
- 3 colourants
- 2 amphoteric cleansers
- 2 secondary cleansers
- 2 humectants
- 2 film formers
- 2 conditioning agents
- 2 named fragrance allergens
- 1 solvent
- 1 olefin sulfonate cleanser
- 1 salt
Ingredient list captured 2026-08-22. Formulas change, so check the package in your hand when an ingredient matters to you.
Price · 8.5 oz
Seen at
$30
Good value under
$11
Priced above the products that do the same job. Stores sell it above the $11 line; products that do this job typically go for about $11 at this size.
Sizes
8.5 ozusual store size
$30
$3.65/oz
33.81 oz
$96
$2.84/oz
The 33.81 oz costs 22% less per ounce than the 8.5 oz.
Show the price ladder
Where we’ve seen it4 listings · 3 stores
8.5 ozusual store size
-
Habit Shop
$30.008.5 oz · $3.53/ozAug 30Lowest per oz
-
Hannah Smith Stylist
$32.008.5 oz · $3.77/ozAug 30
-
Olaplex (manufacturer)
$34.008.45 oz · $4.02/ozAug 22
33.81 ozBest per ounce
-
Olaplex (manufacturer)
$96.0033.81 oz · $2.84/ozAug 22Lowest per oz
Sorted by price per ounce. Dated observations from our research, not live prices. Direct store pages, no affiliate links. We don’t sell this product.
How we work this out
- 8.5 oz is the size stores list most often; every comparison on this page is made at it. Other sizes are shown in the Sizes row and the store list.
- Seen at $30 is the price we have observed for the 8.5 oz. We need three stores before we call a price commonly seen.
- Good value under $11 comes from the 7 products we score as doing the same job as this one. A quarter of them cost less than $1.29/oz; at 8.5 oz that is $11. Under that line you are paying less than most of them.
- Each size is guarded on its own, so a multipack or a marketplace listing at one size cannot move another.
- About $11 is what those same products typically cost at this size: the midpoint of their prices per ounce, scaled to 8.5 oz.
Formula
10
Formula score
10 of 10
This is a complete shampoo formula. It is also above the range for shampoos per ounce, with 5 close matches selling for meaningfully less.
How the score is counted
- 5 products that do the same job cost less per ounce
- Costs more per ounce than 81% of the 1544 shampoos we’ve priced
- Covers 7 of the 7 things a shampoo should do
- Reviewers mention 2 things they like about how it performs
- A working detergent systemWhat actually removes oil and product.3 pts
- Slip for detanglingReduces the force it takes to comb wet hair.2 pts
- A humectantBinds water into the hair.1 pt
- A hard-water chelatorBinds the minerals that dull hair in hard water.1 pt
- A pH adjusterBrings the formula to the acidic pH hair prefers.1 pt
- No detergent-dependent filmNothing that needs a clarifying wash to remove.1 pt
- Fragrance kept out of the top eightScent as a finishing touch, not a major share.1 pt
The formula score measures completeness for the job: a weighted share of the systems this product type is usually built around that we find in this list. It does not rate how well the product works or its quality, and it never compares across product types.
Does the same job, for less
Formulas that do the same things (cleanse, condition, coat or hold) for less per ounce. Scent, texture and where you buy them can still differ.
L'Oreal ParisSame function
EverPure Silver Care Shampoo
$1.29/oz $2.36/oz less
- Sulfate-free
- Protein-free
- Deep clean
- Differs
Sun BumLowest cost per oz
Blonde Purple Shampoo
$1.05/oz $2.60/oz less
- Sulfate-free
- Protein-free
- Deep clean
- Function
- Also
NexxusClose function
Clean & Pure Detox Shampoo
$1.33/oz $2.32/oz less
- Sulfate-free
- Protein-free
- Deep clean
- Function
- Also
See more alternatives in the product library
These products do a similar job. We haven’t matched them to you. Find the one that fits your hair, routine and budget
Final decision
Should you buy it?
Similar results available for lessBest user
Colour-treated hair, for washing without sulfates and a protein-free formula
Biggest tradeoff
Worth skipping for anyone sensitive to fragrance, dry or damaged hair, or soft, over-stretchy hair that needs protein
Best alternative if not
Consider L'Oreal Paris EverPure Silver Care Shampoo, for similar results at a lower price
We do not sell products or take placement fees. This page states what the formula and the prices show; the consultation is what matches it to a person.
Claims check
What the brand says, and what the formula shows
Claims are quoted from the brand. We mark a claim supported, partly supported or conflicting only when the ingredient list speaks to it. Everything else stays "stated by the brand". That isn’t a criticism: most claims can’t be checked from a label.
0
SupportedBacked by ingredients
0
Partly supportedSome supporting logic
3
Stated by brandNo clear evidence
0
Potential conflictFormula works against claim
3X brighter hair*
A brand-run study. We report it as stated and do not repeat the number as fact.
—
Stated by brand
Only the brand’s testing shows this.
91% agree hair was less brassy**
A brand-run study. We report it as stated and do not repeat the number as fact.
—
Stated by brand
Only the brand’s testing shows this.
How to read this
We look at the first 10–15 ingredients and what they do in a formula, not at the marketing. If the list doesn't speak to a claim, we don't assume.
Reviewers
What people report
Themes that come up again and again in sourced reviews, written by our researchers in their own words. We don’t store or scrape star ratings.
Effectively neutralizes brassiness and yellow tones on blonde, gray/silver, and highlighted hair
blonde/gray/highlighted hairPraised as fast-acting, needing a shorter processing time than other purple shampoos to visibly reduce brassiness
Some users report an over-toning color shift (hair or hands taking on a blue, green, or purple tint), especially when left on longer than directed or on already cool-toned hair
grey/silver and cool-toned blonde hairA recurring subset of reviewers describe the shampoo leaving hair dry, brittle, or damaged with regular use, even when paired with the matching Nº.5P conditioner
Reviewers note a thin, low-lather texture that does not feel like it fully cleanses and temporarily stains hands purple
More from Olaplex
How this page was made
- Everything above comes from our researched product record: identity, the ingredient list as printed, the brand's own claims, dated prices and review themes our researchers wrote in their own words. No part of this page is written by hand for one product.
- The value band is a fixed label over two stored numbers: this product’s cost per ounce as a percentile of every product of this type we have priced, each at the size it is most often sold in, and how many products we score as doing the same job cost at least a quarter less per ounce.
- Both scores out of ten are defined on this page. The formula score is completeness for the job, computed from a fixed per-format checklist shown beneath the gauge; the price score is cost per ounce against every product of this type we have priced.
- The "Is this right for you?" panel reads only your own consultation answers, and it applies exactly the filters our recommendation engine applies. It is computed when you load the page and is never stored on it.
- 6 sources consulted for this product (5 manufacturer or regulatory, 1 retailer, 0 editorial), last checked 2026-08-25.
- Ingredient references are linked for 9 of 18 product-aware annotations on this page. Fit notes are general formulation guidance. They aren’t a verdict on the finished product or on you.
- We haven’t tested this product in a lab, and we don’t physically test your hair. Formula readings come from the ingredient list. Claims about how it behaves are labelled as the brand's.
- Ingredient order tells you relative amount only above roughly 1%. Prices are what we saw on the dates shown and can change.
- Ingredient names link to our ingredient library, where each entry shows what it does, which product types use it, and where it usually sits on a label across everything we have researched.
- This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
- Formula readings: derivation v23. Record last updated 2026-10-07.
