Skip to main content
K18

PEPTIDE PREP Detox Shampoo

Shampoo / Clarifying, deep-cleaning

  • Shampoo
  • Sulfate-free
  • Silicone-free
  • Curly-method
  • Cruelty-free · brand states
Size8.5 fl oz
Price$34–39commonly seen · 8.5 oz
Price / oz$4.53/ozat 8.5 oz
Where to buy7 stores · $27.00–39.00

Scent:

The ingredient list declares fragrance. What it smells of is not stated, and we do not guess.

Manufacturer page: k18hair.com

Personal fit

Is this right for you?

Complete the consultation to see exactly how well this product fits your hair and your goals. With 2,400+ products in our library we can match exactly the right products to you.

  • In 10 minutes we can identify your exact hair condition and traits.
  • Every product matched against your hair across the 22 factors we check.
  • A personalized routine for your daily life — 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.

$49.00 one-time consultation, no subscription

Add the optional $49/year membership for unlimited adjustments for changes in weather and lifestyle.

Start your consultation

Same job for less elsewhere

$4.53/oz at 8.5 oz — more than 92% of the 805 shampoos , which mostly run $0.81–3.01/oz.

View alternatives

Great for

Colour-treated hairthat fades faster in a sulfate wash
Fast-oiling scalpsthat need a real reset wash
Curly-method routinesno sulfates and no water-insoluble silicones
Hard waterand swimmers dealing with mineral deposit
Fine hairthat flattens under most products
Silicone-free routinesno silicones appear in the list

Maybe skip if

this product carries a scent
Dry or damaged haira strong detergent system strips as it cleans
Tight budgetsit sits in the upper price tiers

Whether this much cleansing is right for you depends on how fast your scalp oils, how much product you layer, and your water — that is what the consultation works out.

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

Removes oil, buildup, and most residue — a reset wash.

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) Moderate

Humectants in the working part of the formula.

Scalp active None

No over-the-counter scalp active.

Hard-water defence Chelators present

Chelators are present — they bind hard-water and pool minerals.

Needs detergent to remove No

Nothing here needs a detergent wash to remove.

Protein Minor

Protein appears, low enough to be a supporting ingredient.

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.

IngredientWhat it doesWhy it mattersChip
WaterWater (Aqua) (Eau) solvent The base everything else is dissolved in Neutral
Sodium C14-16 Olefin Sulfonate olefin sulfonate cleanser — Cleanses
Cocamidopropyl Hydroxysultaine amphoteric cleanser — Cleanses
Salicylic Acid active The over-the-counter active Active
Charcoal Powder absorbent — Neutral
SH-Oligopeptide-78 protein Firms up soft, over-stretchy hair Protein
Panthenol humectant Pulls water into the hair Detangles
Glycerin humectant Pulls water into the hair Moisturizes
FragranceFragrance (Parfum) fragrance The scent Fragrance
Benzyl Salicylate fragrance The scent Fragrance
Limonene fragrance The scent Fragrance
Hydroxycitronellal fragrance The scent Fragrance
What the list leaves out, and what it carriesThe list carries no sulfates, silicones, or drying alcohols. Fragrance is on the label. Hard-water chelators are present.
Full ingredient list (24)

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 · 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 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 ingredient

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

    May suitBuild-up-sensitive routines

    A 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 hair

    Sulfate-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.

    PubChem
    • olefin sulfonate cleanser
    • cleanser
  • 3 Cocamidopropyl Hydroxysultaine
    General function

    A mild co-cleanser that keeps foam stable in hard water.

    Leading ingredient

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

    May suitDry, coarse, or high-porosity hair

    Mild cleansing leaves more surface lubrication in place on hair that dries out quickly.

    May suitVery dry or highly damaged hair

    One 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 routines

    The mildest detergents are also the least complete: a routine that deposits films needs something stronger periodically.

    • amphoteric cleanser
    • secondary cleanser
    • cleanser
  • 4 Salicylic Acid
    General function

    An oil-soluble acid that loosens flakes and clears build-up around the follicle. In dandruff shampoos it appears in the drug facts panel with a stated percentage.

    Supporting ingredient

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

    PubChem
    • active
    • exfoliant
  • 5 Charcoal Powder
    General function

    Activated charcoal, used to absorb oil and for a clarifying claim. It also tints the product black.

    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 dry powder takes up oil and adds friction between strands, which is most of what root lift in fine hair actually is.

    • absorbent
    • powder
  • 6 SH-Oligopeptide-78
    General function

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

    Supporting ingredient

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

    May not suitProtein-sensitive hair

    A large surface-depositing protein. If protein reliably makes your hair feel rigid, this is the form most likely to do it.

    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
  • 7 Panthenol
    General function

    Provitamin B5. It draws in water and penetrates the strand a little, which is why it is the standard ingredient for softness and shine claims.

    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

    It hydrates without adding oil or a film, which is the combination fine hair usually needs.

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

    Deposits a lubricating layer that makes combing easier, which is most of what stops mechanical damage adding to frizz.

    May suitVery dry or highly damaged hair

    A humectant that also penetrates the cuticle, so it holds water inside the strand rather than only on the surface.

    PubChem
    • humectant
    • conditioning agent
    • vitamin
  • 8 Glycerin
    General function

    A small water-loving molecule that draws moisture into the hair and holds it there. It is the most common softening ingredient in conditioners and leave-ins.

    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

    High-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 hair

    Binds 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 hair

    Water 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.

    Scientific Reports
    • humectant
  • ▾Below about this point, order stops being meaningful — these are typically used at 1% or less.
  • 9 Sodium Phytate
    General function

    A rice-derived chelator that binds hard-water minerals without EDTA.

    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

    Binds the calcium and magnesium in hard water, which is what stops mineral deposits accumulating on the strand wash after wash.

    May suitGray, silver, or brass-prone hair

    Copper and iron carried in tap water deposit on the strand and read as a dull, warm cast on gray or light hair. A chelator holds those metals in solution so the wash carries them off.

    PubChem
    • hard-water chelator
  • 10 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.

    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 suitCurls or waves needing flexible hold

    Gums thicken and set soft, which gives definition that bends rather than a rigid cast.

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

    Cationic conditioners bind to the negatively charged damaged cuticle, laying it flat and cutting the friction that causes combing breakage.

    May suitMaximum-hold styling

    A styling polymer dries into a film across the strands, which is what makes a shape hold instead of relax.

    • conditioning agent
    • polymer
    • gum
  • 11 Caprylyl Glycol
    General function

    A gentle preservative helper that also holds a little moisture.

    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 suitVery dry or highly damaged hair

    Humectants bind water into the strand, and water — not oil — is what makes dry hair flexible instead of brittle.

    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
    • preservative
    • humectant
  • 12 Caprylhydroxamic Acid
    General function

    A coconut-derived preservative booster that also binds trace metals.

    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

    Binds the calcium and magnesium in hard water, which is what stops mineral deposits accumulating on the strand wash after wash.

    May suitGray, silver, or brass-prone hair

    Copper and iron carried in tap water deposit on the strand and read as a dull, warm cast on gray or light hair. A chelator holds those metals in solution so the wash carries them off.

    PubChem
    • preservative
    • hard-water chelator
  • 13 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
  • 14 Potassium Hydroxide
    General function

    A strong base used in trace amounts to set pH; it is fully neutralised in the finished product.

    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.

    DependsFrizz-prone, damaged, or high-friction hair

    pH 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.

    PubChem
    • pH adjuster
  • 15 Sodium Hydroxide
    General function

    A strong base used in trace amounts to raise pH; fully neutralised in the finished product.

    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.

    DependsFrizz-prone, damaged, or high-friction hair

    The alkali half of a pH-adjusting pair, used in small amounts to bring a formula up to its target rather than to make it alkaline. Alkaline conditions raise the fibre's surface charge and lift the scales — but the finished pH is not on the label.

    International Journal of Trichology
    • pH adjuster
  • 16 Sodium Chloride
    • salt
    • thickener
  • 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 Benzyl Salicylate
    General function

    A soft floral fragrance component listed 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
  • 19 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 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 Hydroxycitronellal
    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.

    PubChem
    • fragrance
    • named fragrance allergen
  • 21 Citrus Aurantium Dulcis Flower Oil
    General function

    The essential oil of Citrus Aurantium. Essential oils are aromatic — they are in the formula for scent, and they are a common source of declared fragrance allergens.

    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

    Essential 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
  • 22 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 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

    Essential 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
  • 23 Citrus Limon (Lemon) Peel Oil · Citrus Limon Peel Oil
    General function

    A cold-pressed citrus oil used for a fresh scent; naturally high in limonene.

    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

    Essential 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
  • 24 Tetramethyl Acetyloctahydronaphthalenes
    General function

    A synthetic musk or woody-amber note used as a fragrance base.

    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

  • 8 fragrances
  • 3 humectants
  • 3 hard-water chelators
  • 3 pH adjusters
  • 3 named fragrance allergens
  • 3 botanical extracts
  • 3 essential oils
  • 2 cleansers
  • 2 preservatives
  • 1 solvent
  • 1 olefin sulfonate cleanser
  • 1 amphoteric cleanser
  • 1 secondary cleanser
  • 1 active

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

Price · 8.5 oz

Commonly seen $34–39 Midpoint $38.50 · 6 stores · checked Aug 30
Good value under $9 Under $1.10/oz it costs less than three-quarters of the 8 products we score as doing the same job

Priced above the products that do the same job. Stores sell it above the $9 line; products that do this job typically go for about $17 at this size.

Show the price ladder
Where we’ve seen it7 listings · 7 stores

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
  1. 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.
  2. Commonly seen is the middle half of current prices for the 8.5 oz at recognised stores — the cheapest quarter and the dearest quarter are left out, so one sale or one overpriced listing can’t move it.
  3. Good value under $9 comes from the 8 products we score as doing the same job as this one. A quarter of them cost less than $1.10/oz; at 8.5 oz that is $9. Under that line you are paying less than most of them.
  4. About $17 is what those same products typically cost at this size — the midpoint of their prices per ounce, scaled to 8.5 oz.

Formula

Formula score
10 of 10

Sold through specialty beauty at a price 6 products that do the same job undercut — the counter is part of what you are paying for.

How the score is counted
  • 6 products that do the same job cost less per ounce
  • Costs more per ounce than 92% of the 805 shampoos we’ve priced
  • Covers 7 of the 7 things a shampoo should do
  • Reviewers mention 4 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 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, for less

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.

It's a 10Lowest cost per oz Miracle Volumizing Daily Shampoo $1.30/oz $3.23/oz less
  • Sulfate-free
  • Deep clean
  • Curly method
· Close function
Function
  • Film formers
Also
  • Salon tier
  • 10 oz bottle
Compare
CHIClose function Royal Treatment Volume Shampoo $1.53/oz $3.00/oz less
  • Sulfate-free
  • Deep clean
  • Curly method
Function
  • Film formers
Also
  • Salon tier
  • 12 oz bottle
Compare
Kenra PlatinumClose function Luxe Shine Shampoo $3.29/oz $1.24/oz less
  • Deep clean
  • Hard water
Function
  • Film formers
Also
  • Sold through salons
Compare

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

Suits every hair pattern

Final decision

Should you buy it?

Good for the right person, not the lowest cost
Best user

Colour-treated hair — for washing without sulfates and a proper reset wash

Biggest tradeoff

Not ideal for anyone sensitive to fragrance, dry or damaged hair, or people shopping on a budget

Best alternative if not

It's a 10 Miracle Volumizing Daily 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, 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.

1
SupportedBacked by ingredients
0
Partly supportedSome supporting logic
1
Stated by brandNo clear evidence
0
Potential conflictFormula works against claim
Deeply cleanses hair and scalp with a non-stripping, pH-optimized lather

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

—

Stated by brand

Can’t be confirmed from label.

Removes buildup without stripping color

The detergent system is strong enough to strip build-up.

  • Sodium C14-16 Olefin Sulfonate
  • Cocamidopropyl Hydroxysultaine
  • Salicylic Acid
Supported

Resets a coated scalp.

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.

Reviewers

What people report

Recurring themes our researchers wrote in their own words from sourced reviews. We do not store or scrape star ratings.

Effectively removes product buildup and leaves scalp/hair feeling squeaky clean

general users, including some describing heavy stylers or hard water buildup

Does not strip color despite being a clarifying/detox formula

color-treated hair users, including blonde highlights

Used as a prep step that reviewers feel improves absorption/results of the K18 leave-in mask afterward

multi-product K18 routine users

Some reviewers with fine or low-porosity hair report it is the first clarifying product that actually made a difference for them

fine/low-porosity hair reviewers

More from K18

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.
  • 5 sources consulted for this product (4 manufacturer or regulatory, 1 retailer, 0 editorial), last checked 2026-08-25.
  • Ingredient references are linked for 12 of 21 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 2026-08-25.

Your personalized hair plan

One thoughtful questionnaire, about 30 minutes, and a plan built around your hair — with the reason behind every recommendation.

Free to complete · $49.00 once to unlock your full plan · No subscription · Nothing you must buy

Start your consultation