Side by side
K18 DAMAGE SHIELD pH Protective Shampoo vs K18 PEPTIDE PREP Detox Shampoo
96% function match · 12 of the 13 functions we compared match Formula overlap 52%. K18 DAMAGE SHIELD pH Protective Shampoo and K18 PEPTIDE PREP Detox Shampoo share 4 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.
- DAMAGE SHIELD pH Protective Shampoo — colour-treated hair
- PEPTIDE PREP Detox Shampoo — colour-treated 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”.
- 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
- 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
- Scents bother youthis product carries a scent
- Dry or damaged haira strong detergent system strips as it cleans
- Tight budgetsit sits in the upper price tiers
- Scents bother youthis product carries a scent
- Dry or damaged haira strong detergent system strips as it cleans
- Tight budgetsit sits in the upper price tiers
More facts about each one
- sulfate-free
- silicone-free
- curly-method compatible
- sulfate-free
- silicone-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
DAMAGE SHIELD pH Protective Shampoo
PEPTIDE PREP Detox Shampoo
Full ingredient list — DAMAGE SHIELD pH Protective Shampoo (24)
-
1
Water
- solvent
-
2
Sodium C14-16 Olefin Sulfonate
- olefin sulfonate cleanser
- cleanser
-
3
Cocamidopropyl Betaine
- amphoteric cleanser
- secondary cleanser
- cleanser
-
4
Sodium Methyl 2-Sulfolaurate
- cleanser
-
5
Sodium Lauryl Sulfoacetate
- mild anionic cleanser
- cleanser
-
6
SH-Oligopeptide-78
- protein
-
7
Panthenol
- humectant
- conditioning agent
- vitamin
-
8
Glycerin
- humectant
- Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
9
Sodium Phytate
- hard-water chelator
-
10
Guar Hydroxypropyltrimonium Chloride
- conditioning agent
- polymer
- gum
-
11
Disodium 2-Sulfolaurate
- cleanser
-
12
Caprylyl Glycol
- preservative
- humectant
-
13
Caprylhydroxamic Acid
- preservative
- hard-water chelator
-
14
Benzoic Acid
- preservative
-
15
Citric Acid
- pH adjuster
- hard-water chelator
-
16
Sodium Hydroxide
- pH adjuster
-
17
Sodium Chloride
- salt
- thickener
-
18
Fragrance
- fragrance
- declared fragrance
-
19
Limonene
- fragrance
- named fragrance allergen
-
20
Hydroxycitronellal
- fragrance
- named fragrance allergen
-
21
Citrus Aurantium Dulcis Flower Oil
- botanical extract
- essential oil
- fragrance
-
22
Citrus Aurantium Peel Oil
- botanical extract
- essential oil
- fragrance
-
23
Citrus Limon (Lemon) Peel Oil
- botanical extract
- essential oil
- fragrance
-
24
Tetramethyl Acetyloctahydronaphthalenes
- fragrance
Full ingredient list — PEPTIDE PREP Detox Shampoo (24)
-
1
Water
- solvent
-
2
Sodium C14-16 Olefin Sulfonate
- olefin sulfonate cleanser
- cleanser
-
3
Cocamidopropyl Hydroxysultaine
- amphoteric cleanser
- secondary cleanser
- cleanser
-
4
Salicylic Acid
- active
- exfoliant
-
5
Charcoal Powder
- absorbent
- powder
-
6
SH-Oligopeptide-78
- protein
-
7
Panthenol
- humectant
- conditioning agent
- vitamin
-
8
Glycerin
- humectant
- Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
9
Sodium Phytate
- hard-water chelator
-
10
Guar Hydroxypropyltrimonium Chloride
- conditioning agent
- polymer
- gum
-
11
Caprylyl Glycol
- preservative
- humectant
-
12
Caprylhydroxamic Acid
- preservative
- hard-water chelator
-
13
Citric Acid
- pH adjuster
- hard-water chelator
-
14
Potassium Hydroxide
- pH adjuster
-
15
Sodium Hydroxide
- pH adjuster
-
16
Sodium Chloride
- salt
- thickener
-
17
Fragrance
- fragrance
- declared fragrance
-
18
Benzyl Salicylate
- fragrance
- named fragrance allergen
-
19
Limonene
- fragrance
- named fragrance allergen
-
20
Hydroxycitronellal
- fragrance
- named fragrance allergen
-
21
Citrus Aurantium Dulcis Flower Oil
- botanical extract
- essential oil
- fragrance
-
22
Citrus Aurantium Peel Oil
- botanical extract
- essential oil
- fragrance
-
23
Citrus Limon (Lemon) Peel Oil
- botanical extract
- essential oil
- fragrance
-
24
Tetramethyl Acetyloctahydronaphthalenes
- fragrance
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.
DAMAGE SHIELD pH Protective Shampoo
Clinically proven to provide conditioning protection against damage from UV rays, mechanical styling, and environmental aggressors for up to 3 days
Stated by brandOnly the brand’s testing shows this.
PEPTIDE PREP Detox Shampoo
Deeply cleanses hair and scalp with a non-stripping, pH-optimized lather
Stated by brandCan’t be confirmed from label.Removes buildup without stripping color
SupportedResets a coated scalp.
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.
Both praised for a light feel and how it cleanses.
DAMAGE SHIELD pH Protective Shampoo
Pleasant scent called out repeatedly as a selling point
general usersReported to visibly repair brittle, dry, or chemically damaged hair over a few weeks of use
users with color-treated/bleached or heat-damaged hairLeaves hair clean and soft without feeling weighed down
general users, several noting fine or fine-to-medium hairSome reviewers pair it explicitly with the leave-in mask and report better results using the full system rather than the shampoo alone
repeat/multi-product K18 usersPEPTIDE PREP Detox Shampoo
Effectively removes product buildup and leaves scalp/hair feeling squeaky clean
general users, including some describing heavy stylers or hard water buildupDoes not strip color despite being a clarifying/detox formula
color-treated hair users, including blonde highlightsUsed as a prep step that reviewers feel improves absorption/results of the K18 leave-in mask afterward
multi-product K18 routine usersSome 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 reviewersPrice 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.
$4.53/oz vs $4.59/oz — within about the same cost per ounce.
Every mark sits on one distribution because these are compared against the same set: 817 shampoos 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.
DAMAGE SHIELD pH Protective Shampoo · PEPTIDE PREP Detox Shampoo · All shampoos 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.
- 10 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.
Still unsure? Take your consultation or browse more products.
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