K18 Leave-In Molecular Repair Hair Mask
Evidence-led ingredient analysis, a transparent clean score out of 100 and cleaner, effective alternatives at three price levels.
Best for
Dry & Damaged Hair
Why Selenssa recommends it
Utilises a patented biomimetic peptide sequence to reconnect broken polypeptide chains and disulfide bonds inside the hair core. Its rinse-free, leave-in formula permanently reverses heat and bleach damage in four minutes.
Key actives
K18Peptide™ (sh-Oligopeptide-78), Hydrolyzed Wheat Protein, Glycerin
Clean highlights
Vegan · Cruelty-free · Colour-safe · Sulphate free
Selenssa Score 86/100 · £70.00
Want to see how this compares? See The Selenssa 3 →K18
Leave-In Molecular Repair Hair Mask
Haircare · Budget: £70.00
4.4 (12,000 reviews)· across Cult Beauty, Space NK, LookFantastic, Amazon UK, Sephora UK
Ingredients: AI-inferred — not yet verified
Inferred ingredient list based on standard published formulation. A scientifically advanced leave-in hair treatment centered around a patented bond-repair peptide (sh-Oligopeptide-78). While exceptional for molecular keratin repair, the formula contains high concentrations of Alcohol Denat. (which may be drying or irritating to sensitive scalps) alongside undisclosed fragrance and common floral allergens.
Hazard categories
Estimated score out of 100
Formulation score is fixed across Selenssa · Community effectiveness awaiting more reports
Based on publicly available ingredients, following our methodology. Not medical advice — always check the physical label, especially for allergies. How we score →
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K18 Leave-In Molecular Repair Hair Mask is an effective choice for chemically or heat-damaged hair that requires structural repair. If you have a dry or sensitive scalp, apply the product strictly to the mid-lengths and ends to avoid drying or irritating effects from the denatured alcohol and fragrance content.
Be cautious if
Individuals with dry scalp conditions, contact allergies to fragrance components (Limonene, Linalool, Geraniol, Hexyl Cinnamal), or severe sensitivity to drying alcohols.
Against your clean standard
Meets modern clean performance standards overall, with minor cautions noted for Alcohol Denat. and fragrance allergens.
Where this score comes from
- Source
- No source record on file yet
- Source page
- —
- Retrieved
- —
- Evidence snapshot
- Not captured
Score history
No score changes have been recorded for this product yet.
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Does K18 Leave-In Molecular Repair Hair Mask contain parabens, sulfates or fragrance?
A straight yes or no for the ingredient groups people most often want to avoid, checked against this product's published formulation.
Free from parabens
Preservatives; the longer-chain ones (propyl, butyl) carry the endocrine questions.
Free from sulfates (sls / sles)
Strong cleansing agents that can strip a compromised barrier.
Free from silicones
Slip and occlusion; cyclic silicones (D4/D5/D6) are the environmentally restricted ones.
Contains fragrance / parfum
Found: fragrance (parfum). Undisclosed fragrance blends are the most common trigger for sensitised skin.
Contains essential oils
Found: geraniol, linalool, limonene. Naturally derived, but among the most frequently reported contact allergens.
Contains drying alcohol
Found: alcohol denat., isopropyl alcohol, phenoxyethanol. Fine in small amounts for texture; high up the list it can dehydrate.
Free from formaldehyde releasers
Preservatives that slowly release formaldehyde.
Free from chemical uv filters of concern
Restricted or debated filters with endocrine or reef-persistence questions.
Is K18 Leave-In Molecular Repair Hair Mask non-comedogenic?
This formulation contains 1 ingredient commonly associated with clogged pores — cetearyl alcohol. That does not make it unsuitable for everyone: comedogenicity depends on concentration, the rest of the formula and your own skin. If you are acne-prone, patch test or choose one of the alternatives below.
Is K18 Leave-In Molecular Repair Hair Mask safe for sensitive skin?
Usually tolerated, but patch test if your skin reacts easily.
- Contains fragrance or parfum
- Contains essential oils or common fragrance allergens
- Contains a drying alcohol
Ingredients worth knowing about: Alcohol Denat., Fragrance (Parfum), Geraniol, Linalool, Hexyl Cinnamal, Limonene.
K18 Leave-In Molecular Repair Hair Mask full ingredients list
21 ingredients analysed, in the order Selenssa assessed them. Concentration generally falls as you move down the list.
Water (Aqua) (Eau), Alcohol Denat., Propylene Glycol, Cetearyl Alcohol, Dicaprylyl Ether, Cetyl Esters, Behentrimonium Chloride, Polysorbate 20, sh-Oligopeptide-78 (K18Peptide™), Hydrolyzed Wheat Protein, Hydrolyzed Wheat Starch, Isopropyl Alcohol, Tocopherol, Phenoxyethanol, Potassium Sorbate, Citric Acid, Fragrance (Parfum), Geraniol, Linalool, Hexyl Cinnamal, Limonene.
The actives doing the work: sh-Oligopeptide-78 (Targeted bio-active peptide that helps reconnect damaged hair polypeptide chains.); Hydrolyzed Wheat Protein (Binds moisture and strengthens hair strand elasticity.); Tocopherol (Provides antioxidant protection against environmental hair damage.).
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