Side by side
K18 Leave-In Molecular Repair Hair Mask vs SEEN Leave-In Conditioner, Fragrance Free
74% function match · 7 of the 10 functions we compared match Formula overlap 40%. K18 Leave-In Molecular Repair Hair Mask and SEEN Leave-In Conditioner, Fragrance Free share 2 ingredients among each other's most prominent.
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.
- Leave-In Molecular Repair Hair Mask — protein-hungry hair
- Leave-In Conditioner, Fragrance Free — fragrance-free
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”.
Compared at different sizes — 5 oz against 1.7 oz. Per-ounce prices favour the larger bottle.
- Protein-hungry hairthat stretches and stays stretched when wet
- Maximum slipfor hair that tangles the moment it is wet
- Dry, thirsty hairhumectants and emollients both sit up front
- Curly-method routinesno sulfates and no water-insoluble silicones
- Fragrance-freeno fragrance (parfum) on the label
- Protein-sensitive hairthat stiffens when protein is added
- Maximum slipfor hair that tangles the moment it is wet
- Dry, thirsty hairhumectants and emollients both sit up front
- Scents bother youthis product carries a scent
- Protein-sensitive hairthat goes stiff or straw-like on protein
- Very dry or damaged hairit contains fast-drying alcohol
- Hair that needs proteinthere is none in this list
- Dry or very humid airwhere heavy humectants work against you
- Tight budgetsit sits in the upper price tiers
More facts about each one
- sulfate-free
- silicone-free
- curly-method compatible
- sulfate-free
- silicone-free
- fragrance-free
- protein-free
- curly-method compatible
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.
$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
What only one of them carries
Leave-In Molecular Repair Hair Mask
Leave-In Conditioner, Fragrance Free
Full ingredient list — Leave-In Molecular Repair Hair Mask (23)
-
1
Water
- solvent
-
2
Alcohol Denat.
- drying alcohol
- solvent
-
3
Propylene Glycol
- humectant
- solvent
-
4
Cetearyl Alcohol
- fatty alcohol
- emollient
- thickener
-
5
Dicaprylyl Ether
- light ester
- emollient
-
6
Cetyl Esters
- light ester
- emollient
- thickener
-
7
Behentrimonium Chloride
- conditioning agent
- cleanser
-
8
Polysorbate 20
- solubilizer
- emulsifier
-
9
SH-Oligopeptide-78
- protein
-
10
Hydrolyzed Wheat Protein
- film former
- protein
- hydrolysed protein
-
11
Hydrolyzed Wheat Starch
- film former
- starch
-
12
Isopropyl Alcohol
- drying alcohol
- solvent
- Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
13
Tocopherol
- antioxidant
- vitamin
-
14
Phenoxyethanol
- preservative
-
15
Potassium Sorbate
- preservative
-
16
Citric Acid
- pH adjuster
- hard-water chelator
-
17
Fragrance
- fragrance
- declared fragrance
-
18
Geraniol
- fragrance
- named fragrance allergen
-
19
Linalool
- fragrance
- named fragrance allergen
-
20
Hexyl Cinnamal
- fragrance
- named fragrance allergen
-
21
Benzyl Alcohol
- preservative
- solvent
-
22
Amyl Salicylate
- fragrance
- named fragrance allergen
-
23
benzaldehyde
- fragrance
Full ingredient list — Leave-In Conditioner, Fragrance Free (20)
-
1
Water
- solvent
-
2
C13-15 Alkane
- emollient
- solvent
-
3
Cetearyl Alcohol
- fatty alcohol
- emollient
- thickener
-
4
Glycerin
- humectant
-
5
Squalane
- emollient
- conditioning agent
-
6
Behentrimonium Chloride
- conditioning agent
- cleanser
-
7
Hydrolyzed Ceratonia Siliqua Seed Extract
- botanical extract
- film former
-
8
Moringa Oleifera Seed Extract
- botanical extract
-
9
Bisabolol
- conditioning agent
- botanical extract
-
10
Zea Mays (Corn) Starch
- starch
- powder
-
11
Polyquaternium-7
- conditioning agent
- film former
- polymer
-
12
Guar Hydroxypropyltrimonium Chloride
- conditioning agent
- polymer
- gum
- Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
13
Tocopherol
- antioxidant
- vitamin
-
14
Disodium EDTA
- hard-water chelator
-
15
Ethylhexylglycerin
- preservative
- emollient
-
16
Potassium Sorbate
- preservative
-
17
Disodium Phosphate
- pH adjuster
- salt
-
18
Sodium Benzoate
- preservative
-
19
Citric Acid
- pH adjuster
- hard-water chelator
-
20
Phenoxyethanol
- preservative
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.
Leave-In Molecular Repair Hair Mask
4-minute leave-in treatment to reverse hair damage
Stated by brandCan’t be confirmed from label.Works on the molecular level to reverse hair damage in just 4 minutes
Stated by brandCan’t be confirmed from label.Repairs damage from bleach + color, chemical services, and heat
SupportedReinforces a damaged strand.Works on all hair types
Stated by brandSee the fit panel instead.
Leave-In Conditioner, Fragrance Free
Reduces frizz by 69%
Stated by brandOnly the brand’s testing shows this.Reduces hair breakage by up to 76% after single use
Stated by brandOnly the brand’s testing shows this.Heat Protection (up to 450°F)
Stated by brandOnly lab testing can show this.UV Protection
Partly supportedIndirect help, not a filter.Color-Safe
SupportedLess fade per wash.Non-comedogenic
Stated by brandCan’t be confirmed from label.
What owners say
What people report
Recurring themes our researchers wrote in their own words from sourced reviews. We do not store or scrape star ratings, and we never balance one product’s themes against another’s by inventing them.
Leave-In Molecular Repair Hair Mask
Strongest praise from users with visibly damaged/over-bleached hair; more modest impact reported on already-healthy hair
chemically damaged hairScent described as subtle/faintly medicinal rather than typical perfumed haircare scent
Price-to-value repeatedly flagged as expensive for the bottle size, though many conclude it is worth it for damaged hair
Mixed on weight -- lightweight for most, but over-applying causes heaviness per a subset of reviewers
Leave-In Conditioner, Fragrance Free
Several reviewers with fragrance sensitivities say the truly fragrance-free formula avoids the headaches, burning scalp or reactions other conditioners cause them.
fragrance-sensitive reviewersMany reviewers say the leave-in controls frizz and adds hydration or definition without weighing hair down.
reviewers with wavy, curly or fine hairA couple of reviewers say other leave-ins or conditioners break them out, but this one and the wider SEEN line does not.
acne-prone reviewersMultiple reviewers use it as one step in a wider SEEN routine alongside the curl cream, serum or deep conditioner.
reviewers layering multiple SEEN productsPrice 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.
$0.01/oz vs $5.80/oz — SEEN Leave-In Conditioner, Fragrance Free costs about 580× more per ounce than K18 Leave-In Molecular Repair Hair Mask.
Every mark sits on one distribution because these are compared against the same set: 491 leave-ins with a computable unit price.
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.
Leave-In Molecular Repair Hair Mask · Leave-In Conditioner, Fragrance Free · All leave-ins 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.
- 6 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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