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K18

Leave-In Molecular Repair Hair Mask

Leave-in / Everyday leave-in, medium-weight

  • Leave-in
  • cream
  • Sulfate-free
  • Silicone-free
  • Moisture-rich
  • Cruelty-free · brand states
Size1.69 fl oz
Price$0.01 Good valueseen at one store · 1.69 oz
Price / oz$0.01/ozat 1.69 oz
Where to buy2 stores · $0.01–75.00

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.

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 21 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.

Start your consultation

Lower cost than most leave-ins

$0.01/oz at 1.69 oz, less than 100% of the 749 leave-ins , which mostly run $1.31–5.50/oz.

Price and stores

Great for

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
Curl definitionfilm formers hold a clump together
Silicone-free routinesno silicones appear in the list

Maybe skip if

this product has a scent
Protein-sensitive hairthat goes stiff or straw-like on protein
Very dry or damaged hairit contains fast-drying alcohol
Dry or very humid airwhere heavy humectants work against you
Tight budgetsit sits in the upper price tiers

Whether this weight suits your hair depends on density, porosity and how much you already layer. That is what the consultation looks at.

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, so this is a detangling formula.

Water-binding (humectants) High

Humectants near the top: binding water is one of its main jobs.

Oils and butters None

No oils or butters in the list.

Protein Prominent

Protein high in the list: a strengthening formula, not a moisture one.

Needs detergent to remove No

Nothing here needs a detergent wash to remove.

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.

IngredientWhat it doesWhy it mattersChip
WaterWater (Aqua) (Eau) solvent The base everything else is dissolved in Neutral
Alcohol Denat. drying alcohol Speeds drying but can leave hair feeling dry Drying
Propylene Glycol humectant Pulls water into the hair Moisturizes
Cetearyl Alcohol fatty alcohol Thickens and conditions (not a drying alcohol) Softens
Dicaprylyl Ether light ester Light slip without much weight Softens
Cetyl Esters light ester Light slip without much weight Softens
Behentrimonium Chloride conditioning agent Conditions and softens so hair combs through Detangles
Polysorbate 20 solubilizer Keeps oils dissolved in water Stabilizes
SH-Oligopeptide-78sh-Oligopeptide-78 (K18PEPTIDE) protein A small amount of protein Protein
Hydrolyzed Wheat Protein film former A supporting film former Protein
Isopropyl Alcohol drying alcohol A small amount, for fast drying Drying
FragranceFragrance (Parfum) fragrance The scent Fragrance
What the list leaves out, and what it carriesThe list carries no sulfates or silicones. Protein sits high: this is a strengthening step rather than a moisture one. Fragrance is on the label. Contains fast-drying alcohol.
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 · Water (Aqua) (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 ingredient

    Listed in the first three ingredients, it is likely a structural part of this formula.

    • solvent
  • 2 Alcohol Denat.
    General function

    Fast-drying alcohol used to make sprays set quickly. In leave-on products it can leave hair feeling dry, especially in high position on the list.

    Leading ingredient

    Listed in the first three ingredients, it is likely a structural part of this formula.

    May suitFine or easily flattened hair

    Evaporates on contact, which is how a spray sets almost instantly and leaves no weight behind it.

    May not suitDry, coarse, or high-porosity hair

    Porous hair gives water up easily as it is; a fast-evaporating solvent high on the list accelerates that.

    May not suitVery dry or highly damaged hair

    It evaporates quickly and takes some water with it. On hair already short of moisture, a formula built on a lot of it can finish drier than it started.

    PubChem
    • drying alcohol
    • solvent
  • 3 Propylene Glycol
    General function

    A small humectant and solvent that keeps formulas stable and helps active ingredients spread.

    Leading ingredient

    Listed in the first three ingredients, it is likely a structural part of this formula.

    May suitFine or easily flattened hair

    Light and water-binding rather than oily, so it adds less weight than oils or butters do.

    May suitVery dry or highly damaged hair

    A small water-binding solvent. It holds moisture and helps the rest of the formula spread evenly over the strand.

    DependsClimate-sensitive or frizz-prone hair

    A humectant follows the air: it holds water in humid conditions and can give it up in very dry ones. Climate decides what it does more than the label does.

    PubChem
    • humectant
    • solvent
  • 4 Cetearyl Alcohol
    General function

    A waxy fatty alcohol - nothing like drying alcohol. It gives conditioners their body and leaves a soft, smoothing film on the hair.

    Supporting ingredient

    Listed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.

    May suitDry, coarse, or high-porosity hair

    The waxy solid that gives a conditioner its body. It deposits a soft lubricating layer, which is most of what makes hair feel smooth after rinsing.

    May suitFrizz-prone, damaged, or high-friction hair

    Deposits with the cationic conditioners and helps them lie flat along the strand, which is where the detangling actually comes from.

    DependsFine or easily flattened hair

    Near the top of a conditioner it is doing most of the conditioning, and most of the weighting, at the same time.

    PubChem
    • fatty alcohol
    • emollient
    • thickener
  • 5 Dicaprylyl Ether
    General function

    A light emollient used for slip without a greasy after-feel.

    Supporting ingredient

    Listed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.

    May suitFine or easily flattened hair

    A light emollient: it softens the surface with noticeably less weight than an oil or a butter.

    May suitFrizz-prone, damaged, or high-friction hair

    Spreads thin and lowers friction between strands without the heaviness of a fixed oil.

    PubChem
    • light ester
    • emollient
  • 6 Cetyl Esters
    General function

    A waxy ester blend that replaces spermaceti in creams. It thickens and leaves a smooth, non-greasy finish.

    Supporting ingredient

    Listed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.

    May suitFine or easily flattened hair

    A light emollient: it softens the surface with noticeably less weight than an oil or a butter.

    May suitFrizz-prone, damaged, or high-friction hair

    Spreads thin and lowers friction between strands without the heaviness of a fixed oil.

    • light ester
    • emollient
    • thickener
  • 7 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.

    Supporting ingredient

    Listed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.

    May suitDry, coarse, or high-porosity hair

    Electrokinetic measurement puts the C22 quat ahead of the C16 ones for deposition: the longer chain adds van der Waals stabilisation on top of the charge binding. That extra deposit is what coarse hair usually needs to comb through.

    May suitFrizz-prone, damaged, or high-friction hair

    A cationic conditioning agent: it binds to the damaged, negatively charged parts of the cuticle and lowers combing friction there.

    DependsBuild-up-sensitive routines

    Substantive by design. A routine with no detergent wash gives it nothing to leave with.

    International Journal of Cosmetic Science
    • conditioning agent
    • cleanser
  • 8 Polysorbate 20
    General function

    Keeps fragrance and oils dissolved in a watery formula so it stays clear.

    Supporting ingredient

    Listed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.

    • solubilizer
    • emulsifier
  • 9 SH-Oligopeptide-78 · sh-Oligopeptide-78 (K18PEPTIDE)
    General function

    A bioengineered peptide used at low levels in scalp and growth-positioned products.

    Secondary ingredient

    Lower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.

    DependsVery dry or highly damaged hair

    Unhydrolysed protein is too large to enter the strand. It sits on the surface, which is a coating effect rather than internal reinforcement.

    • protein
  • 10 Hydrolyzed Wheat Protein
    General function

    Wheat protein broken into fragments small enough to cling to the hair. It adds temporary strength and body; too much can feel stiff.

    Secondary ingredient

    Lower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.

    May suitFrizz-prone, damaged, or high-friction hair

    Filling surface gaps evens out the cuticle, which is part of what makes damaged hair comb and reflect light more like undamaged hair.

    May suitMaximum-hold styling

    Film formers are what hold a style: they dry into a connected film across the strands so the shape resists movement.

    May suitVery dry or highly damaged hair

    Hydrolysed fragments are small enough to sit in the gaps of a worn cuticle for a wash or two, temporarily restoring stiffness and cutting breakage in combing.

    • film former
    • protein
    • hydrolysed protein
  • 11 Hydrolyzed Wheat Starch
    General function

    A starch fragment used for light body and film. It is a carbohydrate, not a protein.

    Secondary ingredient

    Lower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.

    May suitFine or easily flattened hair

    Adds grip and body with no oil attached, which is what lifts fine hair at the root instead of weighing it down.

    DependsCurls or waves needing flexible hold

    How rigid the finish is depends on which polymer it is and what the formula pairs with it, not on there being one.

    DependsMaximum-hold styling

    Starch gives texture and grip rather than a set film; firm hold usually needs a polymer alongside it.

    • film former
    • starch
  • 12 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.

    Secondary ingredient

    Lower in the ordered portion of the list, it is more likely playing a supporting role than defining the formula.

    May suitFine or easily flattened hair

    Evaporates on contact, which is how a spray sets almost instantly and leaves no weight behind it.

    PubChem
    • drying alcohol
    • solvent
  • ▾Below about here, the order stops meaning much. These are usually used at 1% or less.
  • 13 Tocopherol
    • antioxidant
    • vitamin
  • 14 Phenoxyethanol
    • preservative
  • 15 Potassium Sorbate
    • preservative
  • 16 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 zone

    It appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.

    May suitBuild-up-sensitive routines

    Holds hard-water minerals in solution so they rinse away instead of depositing on the hair.

    May suitFrizz-prone, damaged, or high-friction hair

    The 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 hair

    Where a warm cast comes from water minerals rather than from the hair itself, holding those metals in solution is what removes it.

    International Journal of Trichology
    • pH adjuster
    • hard-water chelator
  • 17 Fragrance · Fragrance (Parfum)
    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 zone

    It 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 routines

    Declared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.

    • fragrance
    • declared fragrance
  • 18 Geraniol
    General function

    A rose-scented fragrance component, listed on its own because some people react to it.

    Estimated lower-concentration zone

    It 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 routines

    One 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 Linalool
    General function

    A floral fragrance component listed separately as a recognised contact allergen.

    Estimated lower-concentration zone

    It 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 routines

    One 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.

    PubChem
    • fragrance
    • named fragrance allergen
  • 20 Hexyl Cinnamal
    General function

    A jasmine-like fragrance component named separately as a recognised allergen.

    Estimated lower-concentration zone

    It 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 routines

    One 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.

    PubChem
    • fragrance
    • named fragrance allergen
  • 21 Benzyl Alcohol
    • preservative
    • solvent
  • 22 Amyl Salicylate
    General function

    A soft floral fragrance component named separately as a recognised allergen.

    Estimated lower-concentration zone

    It 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 routines

    One 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 benzaldehyde
    General function

    An individual aroma chemical. It is part of the product's fragrance; brands that print these are disclosing more of the blend than the rules require.

    Estimated lower-concentration zone

    It 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 routines

    Declared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.

    • fragrance

What the whole list adds up to

  • 6 fragrances
  • 5 solvents
  • 4 named fragrance allergens
  • 3 emollients
  • 3 preservatives
  • 2 drying alcohols
  • 2 thickeners
  • 2 light esters
  • 2 proteins
  • 2 film formers
  • 1 humectant
  • 1 fatty alcohol
  • 1 conditioning agent
  • 1 cleanser

Ingredient list captured 2026-08-22. Formulas change, so check the package in your hand when an ingredient matters to you.

Price · 1.69 oz

Seen at $0.01 1 store · checked Aug 30
Good value under $4 Under $2.58/oz it costs less than three-quarters of the 6 products we score as doing the same job

Usually a good value. Most stores sell it under the $4 line, and products that do this job typically go for about $8 at this size.

Show the price ladder
Where we’ve seen it2 listings · 2 stores
  • Dermava
    $0.01
    1.7 oz · $0.01/oz
    Aug 30Lowest per oz
  • k18hair.com
    $75.00
    1.69 oz · $44.36/oz
    Aug 22

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. and 3 listings we don’t count, from grey-market or unverified sellers.

How we work this out
  1. 1.69 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.
  2. Seen at $0.01 is the price we have observed for the 1.69 oz. We need three stores before we call a price commonly seen.
  3. Good value under $4 comes from the 6 products we score as doing the same job as this one. A quarter of them cost less than $2.58/oz; at 1.69 oz that is $4. Under that line you are paying less than most of them.
  4. About $8 is what those same products typically cost at this size: the midpoint of their prices per ounce, scaled to 1.69 oz.

Formula

Formula score
10 of 10

It carries the working systems a leave-in needs and still sits in the lower part of the price range for leave-ins per ounce.

How the score is counted
  • Costs less per ounce than 100% of the 749 leave-ins we’ve priced
  • Covers 6 of the 6 things a leave-in should do
  • Prestige tier, sold at Salons and Sephora
  • Prestige tier
  • Conditioning agents up frontWhat makes wet hair comb through.2 pts
  • A humectantBinds water into the hair.2 pts
  • A light baseWater or a volatile carrier first, so it does not weigh hair down.2 pts
  • Oils or butters in the working zoneSoftens the strand rather than just coating it.2 pts
  • 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

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.

CHILighter feel 44 Iron Guard Thermal Protection Spray $2.09/oz $2.08/oz more
  • Heat protect
  • Protein
  • Lightweight
· Close function
Function
  • Film formers
  • Weight on the hair
Also
  • Salon tier
  • 8 oz bottle
Compare
Coco & EveLighter feel Hair Repairing Leave-in Treatment $20.99/oz $20.98/oz more
  • Protein
  • Curly method
  • Lightweight
· Related function
Function
  • Slip and detangling
  • Weight on the hair
  • Fast-drying alcohol
Also
  • Salon tier
Compare
CHILowest cost per oz 44 Iron Guard Botanical Bliss $0.95/oz $0.94/oz more
  • Heat protect
  • Protein
  • Lightweight
· Related function
Function
  • Film formers
  • Weight on the hair
Also
  • Mint scent
  • Salon tier
  • 8 oz bottle
Compare

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

Suits every hair pattern

Final decision

Should you buy it?

A solid pick for the hair it suits
Best user

Soft, over-stretchy hair who want protein high in the formula and real detangling slip

Biggest tradeoff

Less suited to anyone sensitive to fragrance, hair that stiffens on protein, 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, 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.

1
SupportedBacked by ingredients
0
Partly supportedSome supporting logic
3
Stated by brandNo clear evidence
0
Potential conflictFormula works against claim
4-minute leave-in treatment to reverse hair damage

This is a marketing claim; an ingredient list cannot speak to it.

—

Stated by brand

Can’t be confirmed from label.

Works on the molecular level to reverse hair damage in just 4 minutes

This is a marketing claim; an ingredient list cannot speak to it.

—

Stated by brand

Can’t be confirmed from label.

Repairs damage from bleach + color, chemical services, and heat

Protein sits in the first eight ingredients.

  • Behentrimonium Chloride
  • SH-Oligopeptide-78
  • Hydrolyzed Wheat Protein
Supported

Reinforces a damaged strand.

Works on all hair types

No formula reads the same on every texture; our fit panel is the better guide.

—

Stated by brand

See the fit panel instead.

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.

Strongest praise from users with visibly damaged/over-bleached hair; more modest impact reported on already-healthy hair

chemically damaged hair

Scent 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

More from K18

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.
  • 3 sources consulted for this product (3 manufacturer or regulatory, 0 retailer, 0 editorial), last checked 2026-08-25.
  • Ingredient references are linked for 9 of 17 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 2026-08-25.

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