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Side by side

Kerastase Premiere Filler Fondamental Repairing Anti-Frizz Serum vs Kerastase Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant

77% function match · 7 of the 10 functions we compared match Formula overlap 29%. Kerastase Premiere Filler Fondamental Repairing Anti-Frizz Serum and Kerastase Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant share 3 ingredients among each other's most prominent.

Based on your consultation

Which of these fits your hair?

We check your pattern, moisture need, scalp, fragrance tolerance, weight sensitivity and more against each formula — and say which one lines up.

Your profile at a glance

  • Your answers appear here
  • Your answers appear here
  • Your answers appear here
  • Your answers appear here

When each one is the right call

What each formula is built for, from its own ingredient list.

  • Premiere Filler Fondamental Repairing Anti-Frizz Serum — a wide range of hair
  • Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant — porous, damaged hair

Side by side

Every trait, aligned

One row per trait, read from each product’s own ingredient list and record. A dash means we have not researched that field for that product — it is not a “no”.

Price, size & price per ounce
$46 3.04 oz
$38–43 1.01 oz · $38.02/oz

Compared at different sizes — 3.04 oz against 1.01 oz. Per-ounce prices favour the larger bottle.

Value / price positioning
Not enough priced heat protectants to place it Prestige tier
Same job for less elsewhere $$$$$ Prestige tier · costs more than 100% of the 223 heat protectants we’ve priced
Best for hair types
Straight–Curly Smoothing and thermal products span straight through curly hair. Your hair
Straight–Curly Smoothing and thermal products span straight through curly hair. Your hair
Moisture level Differs
None found No humectants found — nothing here pulls water into the hair. Your hair
Low Humectants appear, but low enough to be a minor part. Your hair
Oils and butters Same
None No oils or butters in the list. Your hair
None No oils or butters in the list. Your hair
Slip / detangling Same
Moderate Conditioning agents are present, lower in the list. Your hair
Moderate Conditioning agents are present, lower in the list. Your hair
Weight on hair Same
Medium Middle of the range — noticeable on fine hair, light on coarse hair. Your hair
Medium Middle of the range — noticeable on fine hair, light on coarse hair. Your hair
Fragrance
Prominent Fragrance sits in the first eight ingredients — a larger share of the formula. Your hair
Present Fragrance is listed; it sits below the working ingredients. Your hair
Protein Same
Minor Protein appears, low enough to be a supporting ingredient. Your hair
Minor Protein appears, low enough to be a supporting ingredient. Your hair
Silicone / wax buildup Same
High Water-insoluble silicones or waxes: a detergent wash is what removes them. Your hair
High Water-insoluble silicones or waxes: a detergent wash is what removes them. Your hair
Clarifying wash needed
Moderate Your hair
Moderate Your hair
Fast-drying alcohol Differs
Present Fast-drying alcohol is present — it speeds drying and can read dry on the hair. Your hair
None No fast-drying alcohol in the list. Your hair
Formula completeness
out of 10
Covers the core
out of 10
Covers the core
Who should choose this
  • A wide range of haira middle-of-the-range weight
  • Porous, damaged hairceramides are in the list
  • Very dry hairno fast-drying alcohol in the list
  • A wide range of haira middle-of-the-range weight
Why you might skip it
  • Scents bother youthis product carries a scent
  • Curly-method routinesthese silicones need a detergent to remove
  • Very dry or damaged hairit contains fast-drying alcohol
  • Scents bother youthis product carries a scent
  • Curly-method routinesthese silicones need a detergent to remove
  • Vegan and cruelty-freeour record does not support both claims here
from the formula stated by the brand reported by reviewers Scale: 1 dot low · 5 dots high, within this product type.
More facts about each one
Type
Heat protectantserum
Heat protectant
Where to buy
Salons · Brand website
Free of
  • sulfate-free
  • sulfate-free
Cruelty-free
Cruelty-free · label states
Not cruelty-free · PETA-listed
Scent
Scented, not described
Scented, not described

Facts as we recorded them. A dash means we have not researched that field for that product — it is not a "no".

The bottom line

The bottom line depends on your hair

Which of these two suits you is a question about your hair, not about them. The consultation answers it — and tells you what your routine needs around it.

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$49.00 once, for your consultation and hair profile. No subscription, no required purchases.

The detail behind the table

Where the readings above come from: the ingredient lists themselves, each brand’s claims checked against them, what owners report, and cost per ounce in context.

Shared and distinct ingredients

Shared and distinct ingredients

Computed from the ingredient lists as printed. "Shared" means both lists carry it; where it sits on each label is stated, because position is what tells you how much.

What both formulas carry

IngredientPremiere Filler Fondamental Repairing Anti-Frizz SerumResistance Serum Therapiste Serum Strengthening Serum Heat Protectant
Water
Neutral
#1Leading
#2Leading
Dimethicone
Buildup
#3Leading
#4Supporting
Amodimethicone
Buildup
#5Below the 1% line
#7Supporting
Fragrance
Fragrance
#6Below the 1% line
#36Below the 1% line
Phenoxyethanol
Stabilizes
#7Below the 1% line
#8Below the 1% line
Linalool
Fragrance
#18Below the 1% line
#14Below the 1% line
Citronellol
Fragrance
#25Below the 1% line
#17Below the 1% line
Geraniol
Fragrance
#28Below the 1% line
#20Below the 1% line

What only one of them carries

Full ingredient list — Premiere Filler Fondamental Repairing Anti-Frizz Serum (28)
Full ingredient list — Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant (36)

Claims check

What each brand says, against what each formula shows

Claims are quoted from each brand. We only mark one supported, partly supported, or conflicting when that product’s ingredient list actually speaks to it.

VerdictsPremiere Filler Fondamental Repairing Anti-Frizz SerumResistance Serum Therapiste Serum Strengthening Serum Heat Protectant
Supported
1
0
Partly supported
1
0
Stated by brand
3
0
Potential conflict
0
0

Premiere Filler Fondamental Repairing Anti-Frizz Serum

  • Protects hair from heat damage up to 450°FStated by brandOnly lab testing can show this.
  • Reduces appearance of split endsPartly supportedSupports the surface, not a treatment.
  • 99% stronger hair; 85% shinier hairStated by brandOnly the brand’s testing shows this.
  • Smooths frizz for up to 72 hoursSupportedSmoother strands, less frizz.
  • Up to 3x smoother and 2x softer hairStated by brandOnly the brand’s testing shows this.

Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant

No claims recorded for this product beyond the ones above.

Price check

Cost per ounce, in context

Cost per ounce against every product of this type we have priced, each at the size it is most often sold in. Value labels are computed from that percentile and from how many products that do the same job cost less; they are comparisons, not judgements about a brand.

Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant

Against 223 heat protectants with a computable unit price.

Value readPremiere Filler Fondamental Repairing Anti-Frizz SerumResistance Serum Therapiste Serum Strengthening Serum Heat Protectant
Label
Not enough priced heat protectants to place itWe need more comparable products before we can place this.
Same job for less elsewhereYou are paying above the range for a formula close to several lower-priced options.

Computed from cost per ounce against every product of this type we have priced, and from how many products that do the same job cost less. It is a comparison, not a judgement about the brand.

Compare with something else

Close formulas to each of these, as their own comparison pages.

Premiere Filler Fondamental Repairing Anti-Frizz Serum · Resistance Serum Therapiste Serum Strengthening Serum Heat Protectant · All heat protectants in the library

How this page was made

  • This page is assembled from the same researched records the individual product pages render: identity, each ingredient list as printed, each brand's own claims, dated price observations, and review themes written in our researchers' own words. Nothing on it is written per comparison.
  • We do not rank these against each other. Which of them suits you depends on your hair, and that is what the consultation works out.
  • The formula similarity percentage is a stored, precomputed number: position-weighted overlap of the two ingredient lists blended with agreement on the attributes we derive. It measures how alike two formulas are, not how well either works.
  • 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.
  • 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.
  • 7 sources were consulted across the products on this page.
  • Ingredient order tells you relative amount only above roughly 1%. Prices are observations on the dates shown and change without notice. We do not sell these products and take no placement fees.
  • This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.

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