90% less breakage after one application
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.
Product image coming soon
Kerastase
Résistance Extentioniste Thermique
Heat protectant / Lotion, medium-weight
- Heat protectant
- cream
- Sulfate-free
- Protein-free
- Not cruelty-free · PETA-listed
Size5.1 fl oz
Price$52seen at one store · 5.1 oz
Price / oz$10.20/ozat 5.1 oz
Where to buy1 store · $52.00–52.00
Scent:
The ingredient list declares fragrance. What it smells of is not stated, and we do not guess.
Manufacturer page: valley-beauty.com
Personal fit
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Factor
Your profile
Fit
Best for hair types
Straight–Curly
Not in your profile
Moisture level
Low
Not in your profile
Oils and butters
None
Not in your profile
Slip / detangling
High
Not in your profile
Weight on hair
Medium
Not in your profile
Fragrance
Present
Not in your profile
Protein
None
Not in your profile
Silicone / wax buildup
High
Not in your profile
Clarifying wash needed
Moderate
Not in your profile
Parabens / preservatives
None of these listed
Not in your profile
Show all 20 factors we check
The rest of what your plan weighs on this product.
Essential oils
None listed
Not in your profile
Fast-drying alcohol
Moderate
Not in your profile
Vegan / cruelty-free
Not cruelty-free · PETA-listed
Not in your profile
Animal-derived ingredients
Not yet verified
Not in your profile
Heavy humectants
Not heavy
Not in your profile
Hard-water defence
None
Not in your profile
UV filter
None listed
Not in your profile
Ingredient list
26 ingredientsAbout average
Not in your profile
Price tier
Prestige
Not in your profile
Where to buy it
Salons · Specialty beauty
Not in your profile
The consultation builds your hair profile, then reads every factor in this table against it — and tells you where this product fits, or what to use instead.
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Your avoid-list
Priced above most heat protectants
$10.20/oz at 5.1 oz — more than 91% of the 223 heat protectants , which mostly run $2.25–7.40/oz.
Great for
Protein-sensitive hairthat stiffens when protein is added
Maximum slipfor hair that tangles the moment it is wet
A wide range of haira middle-of-the-range weight
Maybe skip if
this product carries a scent
Curly-method routinesthese silicones need a detergent to remove
Very dry or damaged hairit contains fast-drying alcohol
Vegan and cruelty-freeour record does not support both claims here
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.
Weight on the hair
Medium
Middle of the range — noticeable on fine hair, light on coarse hair.
Slip and detangling
High
Conditioning agents sit high in the list — this is a detangling formula.
Needs detergent to remove
Yes
Water-insoluble silicones or waxes: a detergent wash is what removes them.
Water-binding (humectants)
Low
Humectants appear, but low enough to be a minor part.
Fast-drying alcohol
Present
Fast-drying alcohol is present — it speeds drying and can read dry on the hair.
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. These 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) | solvent | The base everything else is dissolved in | Neutral |
| Isopropyl Myristate | light ester | Light slip without much weight | Softens |
| Dimethicone | silicone | Spreads heat across the strand | Buildup |
| Triethanolamine | pH adjuster | Fine-tunes the pH | pH balancer |
| Amodimethicone | silicone | A little heat-spreading smoothing | Buildup |
| Phenoxyethanol | preservative | Keeps the product from spoiling | Stabilizes |
| Carbomer | thickener | Adjusts the texture | Holds |
| Polyquaternium-4 | conditioning agent | Adds slip, lower in the list | Detangles |
| Amyl Cinnamal | fragrance | The scent | Fragrance |
| Hexyl Cinnamal | fragrance | The scent | Fragrance |
| Isopropyl Alcohol | drying alcohol | A small amount, for fast drying | Drying |
| Linalool | fragrance | The scent | Fragrance |
What the list leaves out, and what it carriesNo sulfates. Protein-free: this is built for moisture rather than for strengthening. Contains fragrance. The silicones here need a detergent wash to come off.
Full ingredient list (26)
US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order. Annotations keep three readings separate: the ingredient's general function, its role in this product type, and what its position can support.
-
1
Water
· Aqua (Water)
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
Isopropyl Myristate
General function
A very light ester that makes products glide and disappear quickly on the hair.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
PubChemMay suitFine or easily flattened hairA light emollient: it softens the surface with noticeably less weight than an oil or a butter.
May suitFrizz-prone, damaged, or high-friction hairSpreads thin and lowers friction between strands without the heaviness of a fixed oil.
- light ester
- emollient
-
3
Dimethicone
General function
The most common conditioning silicone. It coats the strand for shine, slip, and frizz control, and needs a detergent (not just water) to wash out.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
May suitClimate-sensitive or frizz-prone hairA surface film slows how quickly humidity reaches the cortex, which is what limits swelling-driven frizz in damp air.
May suitFrizz-prone, damaged, or high-friction hairLays a smooth film along the cuticle, which lowers combing friction and flattens the surface irregularities that read as frizz.
May not suitBuild-up-sensitive routinesDimethicone does not disperse in water. On a routine that skips detergent it stays on the hair and accumulates wash after wash.
- silicone
- emollient
- conditioning agent
- ▾Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
4
Triethanolamine
General function
A base used in trace amounts to neutralise acidic polymers so a gel thickens.
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.
PubChemDependsFrizz-prone, damaged, or high-friction hairpH adjusters are how a formula is brought to a chosen acidity, and an acidic formula keeps the cuticle lying flatter than an alkaline one. Which way this one moves the pH depends on the formula, and the finished pH is not on the label.
- pH adjuster
-
5
Amodimethicone
General function
A silicone modified to stick where hair is damaged, so it smooths selectively instead of coating everything. It resists rinsing more than plain dimethicone.
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 suitClimate-sensitive or frizz-prone hairA surface film slows how quickly humidity reaches the cortex, which is what limits swelling-driven frizz in damp air.
May suitFrizz-prone, damaged, or high-friction hairAmino-functional silicone carries a positive charge, so it binds where the cuticle is worn rather than coating evenly. Damaged areas get most of it.
May suitMaximum-hold stylingFilm formers are what hold a style: they dry into a connected film across the strands so the shape resists movement.
- silicone
- conditioning agent
- film former
-
6
Phenoxyethanol
General function
The most common modern preservative; it keeps the product free of bacteria and mould. It sits well below 1% of the formula.
Estimated lower-concentration zonePubChemIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
- preservative
-
7
Carbomer
General function
A thickener that turns a liquid into a clear gel. It also contributes a light hold.
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 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.
- thickener
- polymer
- film former
-
8
Polyquaternium-4
General function
A cellulose-based hold polymer used in gels and sprays for flexible set.
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 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
-
9
Potato Starch Modified
General function
A modified starch. It soaks up oil and water and leaves a dry, slightly grippy feel, which is what puts starches in dry shampoos and texture products.
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 suitFine or easily flattened hairAdds grip and body with no oil attached, which is what lifts fine hair at the root instead of weighing it down.
DependsMaximum-hold stylingStarch gives texture and grip rather than a set film; firm hold usually needs a polymer alongside it.
- starch
- absorbent
-
10
Hydroxypropyl Guar
General function
A modified guar gum used to thicken and give a slippery, cushioned feel.
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 suitCurls or waves needing flexible holdGums thicken and set soft, which gives definition that bends rather than a rigid cast.
May suitMaximum-hold stylingA styling polymer dries into a film across the strands, which is what makes a shape hold instead of relax.
- gum
- thickener
- polymer
-
11
Behentrimonium Chloride
General function
A positively charged conditioning agent that binds to damaged, negatively charged spots on the hair. It is the main detangling ingredient in most rinse-out conditioners.
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 Cosmetic ScienceMay suitFrizz-prone, damaged, or high-friction hairA cationic conditioning agent: it binds to the damaged, negatively charged parts of the cuticle and lowers combing friction there.
DependsBuild-up-sensitive routinesSubstantive by design. A routine with no detergent wash gives it nothing to leave with.
DependsVery dry or highly damaged hairEvery detergent removes some sebum along with the product it is there to wash out. Which detergent it is matters more than that there is one.
- conditioning agent
- cleanser
-
12
Trideceth-6
- emulsifier
- solubilizer
-
13
Amyl 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
-
14
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
-
15
Isopropyl Alcohol
General function
A fast-evaporating alcohol used as a solvent and to speed drying. Well down the list it is a processing aid; near the top it can leave hair feeling dry.
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 suitFine or easily flattened hairEvaporates on contact, which is how a spray sets almost instantly and leaves no weight behind it.
- drying alcohol
- solvent
-
16
Benzyl Alcohol
- preservative
- solvent
-
17
Linalool
General function
A floral fragrance component listed separately as a recognised contact 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
-
18
Hydroxycitronellal
General function
A soft floral 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
-
19
Cetrimonium Chloride
General function
A quick-acting conditioning agent that reduces static and combing force. It also helps keep the formula stable.
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 Cosmetic ScienceMay suitFine or easily flattened hairThe C16 quat binds mostly by charge rather than by chain, so it deposits measurably less than the C22 ones. Less deposit is less conditioning and also less weight, which is usually the trade fine hair wants.
May suitFrizz-prone, damaged, or high-friction hairA cationic conditioning agent: it binds to the damaged, negatively charged parts of the cuticle and lowers combing friction there.
DependsBuild-up-sensitive routinesSubstantive by design. A routine with no detergent wash gives it nothing to leave with.
- conditioning agent
- cleanser
-
20
Citronellol
General function
A rose-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
-
21
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
-
22
Benzyl Cinnamate
General function
A balsamic fragrance component listed 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.
May 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
-
23
Creatine
General function
An amino-acid derivative used in strengthening-positioned products; it is small enough to enter the strand.
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 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.
May suitVery dry or highly damaged hairAmino acids are the smallest protein fraction and bind water as well, so they add far less stiffness than a hydrolysed protein does.
DependsProtein-sensitive hairThe lightest option in the protein family, but still protein — worth watching if protein reliably stiffens your hair.
- amino acid
- conditioning agent
- 24 2-Oleamido-1-3-Octadecanediol
-
25
Taurine
- amino acid
- humectant
-
26
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
What the whole list adds up to
- 8 fragrances
- 7 named fragrance allergens
- 3 solvents
- 3 conditioning agents
- 3 film formers
- 3 polymers
- 3 conditioning agents
- 2 emollients
- 2 silicones
- 2 preservatives
- 2 thickeners
- 2 cleansers
- 2 amino acids
- 1 light ester
Ingredient list captured 2026-09-05. Formulas change — check the package in your hand when an ingredient matters to you.
Price · 5.1 oz
Seen at
$52
Good value under
$19
Priced above the products that do the same job. Stores sell it above the $19 line; products that do this job typically go for about $31 at this size.
Show the price ladder
Where we’ve seen it3 listings · 1 store
How we work this out
- 5.1 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 $52 is the price we have observed for the 5.1 oz. We need three stores before we call a price commonly seen.
- Good value under $19 comes from the 6 products we score as doing the same job as this one. A quarter of them cost less than $3.63/oz; at 5.1 oz that is $19. Under that line you are paying less than most of them.
- About $31 is what those same products typically cost at this size — the midpoint of their prices per ounce, scaled to 5.1 oz.
Formula
8
Formula score
8 of 10
It costs more per ounce than 91% of the 223 heat protectants we’ve priced, and the formula carries the systems the format is built around. Nothing in our library comes close enough on formula to be a cheaper substitute.
How the score is counted
- Nothing in our library does the same job at a lower price
- Costs more per ounce than 91% of the 223 heat protectants we’ve priced
- Covers 5 of the 6 things a heat protectant should do
- Prestige tier, sold at Salons and Specialty beauty
- A film-forming heat spreaderSilicones or polymers that spread heat along the strand.3 pts
- A stated heat claimThe brand names the protection it claims.2 pts
- A light baseWater or a volatile carrier first, so it does not weigh hair down.2 pts
- A humectantBinds water into the hair.1 pt
- Slip for detanglingReduces the force it takes to comb wet hair.1 pt
- Fragrance kept out of the top eightScent as a finishing touch, not a major share.1 pt
The formula score is completeness for the job: the share of the systems this product type is normally built around that we can find in this list, weighted. It is not efficacy, not quality, and it never compares across product types.
Does the same job
Same derived functions — what it cleans, conditions, coats or holds — at a lower cost per ounce. Scent, texture and where you buy it can still differ.
KerastaseLowest cost per oz
Resistance Heat Protecting Leave-In Treatment for Split Ends
$9.80/oz $0.40/oz less
- Heat protect
- Protein-free
- Medium weight
- Differs
MatrixClose function
A Curl Can Dream Scrunch N' Go Defining Spray
- Heat protect
- Protein-free
- Medium weight
- Function
- Also
KerastaseClose function
Premiere Filler Fondamental Repairing Anti-Frizz Serum
$15.13/oz $4.93/oz more
- Medium weight
- Function
- Also
See more alternatives in the product library
These are functional neighbours, not personal recommendations — they are close on formula, not chosen for anyone. Get the one that fits your hair, routine, and budget
Final decision
Should you buy it?
Only if you need exactly thisBest user
Hair that stiffens on protein who want a protein-free formula and real detangling slip
Biggest tradeoff
Less suited to anyone sensitive to fragrance, curly-method routines, or very dry or high-damage hair
Best alternative if not
Nothing in our library matches it closely 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, against what the formula shows
Claims are quoted from the brand. We only mark one supported, partly supported, or conflicting when the ingredient list actually speaks to it; everything else stays "stated by the brand", which is not a criticism — most claims simply cannot be read off a label.
0
SupportedBacked by ingredients
0
Partly supportedSome supporting logic
3
Stated by brandNo clear evidence
0
Potential conflictFormula works against claim
Protects against heat up to 450°F
Heat protection is a performance claim; an ingredient list cannot confirm it.
- Dimethicone
- Amodimethicone
- Carbomer
Stated by brand
Only lab testing can show this.
Reinforces and seals lengths and ends
This is a marketing claim; an ingredient list cannot speak to it.
—
Stated by brand
Can’t be confirmed from label.
How to read this
We look at the first 10–15 ingredients and what they do in a formula — not marketing. If the list doesn't speak to a claim, we don't assume.
More from Kerastase
How this page was made
- Everything above is generated from our researched product record — identity, the ingredient list as printed, the brand's own claims, dated price observations, and review themes written in our researchers' own words. No part of this page is written per 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.
- 4 sources consulted for this product (0 manufacturer or regulatory, 4 retailer, 0 editorial), last checked 2026-09-05.
- Ingredient references are linked for 12 of 20 product-aware annotations on this page. Fit notes are conditional formulation guidance, not a conclusion about the finished product or about you.
- We have not tested this product in a lab and we do not physically test your hair. Formula readings come from the ingredient list; behaviour claims are labelled as the brand's.
- Ingredient order tells you relative amount only above roughly 1%. Prices are observations on the dates shown and change without notice.
- 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 v22. Record last updated 2026-09-05.