The Beauty & Personal Care Brand Builder Series

The Beauty & Personal Care Brand Builder Series

Leave-In Molecular Repair Hair Mask | Manufacturing and Formulation Insights

This page provides an ingredient-level review of Leave-In Molecular Repair Hair Mask by K18. Below you’ll find the publicly available ingredient list, a dynamic ingredient breakdown linked to the FormuNova ingredient database, and a formula structure overview intended for cosmetic founders, product developers, and brand teams researching competitor product architecture in modern hair treatments & masks and related Beauty & Personal Care categories. This page is a formulation and manufacturing review and does not imply or state any association between FormuNova and K18.

Full Ingredient 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, Benzyl Alcohol

Formulation Deep Dive

K18's Leave-In Molecular Repair Hair Mask is formulated as a high-performance bioactive treatment designed to restore hair elasticity and strength at the molecular level. The carrier system utilizes a blend of water, alcohol denat, and propylene glycol to facilitate deep penetration of actives, while cetearyl alcohol and dicaprylyl ether provide a lightweight, emollient texture without heavy residue. The core performance is driven by SH-Oligopeptide-78 (K18Peptide™), which works alongside hydrolyzed wheat protein and hydrolyzed wheat starch to reinforce the hair's structural integrity and moisture retention. The formulation is stabilized with behentrimonium chloride and polysorbate 20, utilizing a preservation system of phenoxyethanol and potassium sorbate to ensure long-term efficacy and microbial stability.

Formula Structure Overview

This formula has a 81% match with ingredients from our research database. Among the matched ingredients, the main functional themes identified are categorized as moisturizer, emollient, conditioner, and barrier support ingredients.

Reviewed Ingredient Coverage
81%
Matched Ingredients
17

Ingredient Analysis

About our ratings
Water GREAT
Purified water serves as the primary, high-quality solvent in most cosmetics.
Solvent
Alcohol GOOD
A fast-evaporating cosmetic alcohol (undenatured ethanol) used as a solvent, astringent and quick-dry base; note the “Alcohol” vs. “Alcohol Denat.”/SD Alcohol 40-B distinction for US markets.
Solvent Astringent
Propylene Glycol GOOD
Attract and retain moisture; solubilize actives; inhibit microbial growth in formulations.
Hydrator Moisturizer Emollient Texture Enhancer Solvent Preservative
Cetearyl Alcohol GOOD
Stabilize and thicken emulsions while depositing a soft, emollient film that improves skin feel and hair manageability.
Moisturizer Emollient Texture Enhancer Conditioner Barrier Support Emulsifier
Dicaprylyl Ether NOT RATED
Cetyl Esters NOT RATED
Behentrimonium Chloride GOOD
A cationic conditioning agent that detangles, de-statics and smooths hair.
Conditioner Anti-Frizz Agent
Polysorbate 20 GOOD
To stabilise oil-in-water or water-in-oil mixtures, reduce interfacial tension, solubilise lipophilic actives, and improve formulation texture and performance in skin and hair care systems.
Texture Enhancer Cleansing Agent Emulsifier Solvent
SH-Oligopeptide-78 (K18Peptide™) NOT RATED
Hydrolyzed Wheat Protein GOOD
To enhance moisture retention, improve skin and hair texture, and strengthen hair fibers.
Hydrator Moisturizer Emollient Texture Enhancer Conditioner Strengthener Soother Anti-Inflammatory Agent Barrier Support Tone Evener Anti-Aging Agent
Hydrolyzed Wheat Starch NOT RATED
Isopropyl Alcohol CAUTION
Dissolves oils, non‑polar residues, and formulation components while aiding rapid evaporation and product delivery performance.
Cleansing Agent Astringent Solvent
Tocopherol (Vitamin E) GREAT
To provide antioxidant protection, moisturize and condition the skin and hair, support the skin’s barrier function, soothe irritation, and protect against environmental damage.
Moisturizer Emollient Conditioner Antioxidant Soother Barrier Support Anti-Aging Agent
Phenoxyethanol GOOD
A broad-spectrum cosmetic preservative that protects water-containing formulas against bacteria, yeast and mold.
Preservative
Potassium Sorbate GOOD
Functions as a preservative (antimicrobial), protecting water-containing formulations primarily against yeasts and molds, with weaker activity against bacteria. Its activity is pH-dependent and strongest in acidic systems (effective below roughly pH 6, optimal near pH 4.4), so it is used in low-pH products and is commonly paired with a second preservative such as sodium benzoate for broad-spectrum coverage.
Preservative
Citric Acid GOOD
Acts mainly as a pH adjuster and buffer and as a chelating agent that protects formula stability and preservation; at higher leave-on levels it also serves as a mild exfoliating AHA.
Chelating Agent Exfoliant
Fragrance FAIR
The aromatic component of a cosmetic — a blended scent that defines a product’s smell and sensory experience, used within IFRA safe-use limits and with required allergen declaration.
Geraniol CAUTION
A naturally-occurring rose-scented terpene alcohol, used as a fragrance component; listed individually as an EU-declared allergen when present above regulatory thresholds.
Linalool CAUTION
A naturally-occurring floral terpene alcohol fragrance component, listed individually as an EU-declared allergen when present above regulatory thresholds.
Hexyl Cinnamal CAUTION
A naturally-occurring jasmine-like aromatic aldehyde, used as a fragrance component; listed individually as an EU-declared allergen when present above regulatory thresholds.
Benzyl Alcohol GOOD
A naturally-occurring aromatic-alcohol preservative and solvent for broad-spectrum protection.
Preservative Solvent
The information provided in this review is based on internal research and publicly available sources. It is intended for general informational purposes only and does not constitute medical, legal, or regulatory advice. We do not guarantee the accuracy or completeness of this information. Users are encouraged to conduct their own research and consult appropriate professionals before making decisions based on this information.

The manufacturing partners for K18 are not publicly disclosed. Many brands work with multiple contract manufacturers across different regions depending on production volume, product type, and regulatory requirements.

Exact sales numbers for K18 are not publicly disclosed.

K18 has successfully captured market share by focusing on a successful balance of marketing and formulation.

Replicating that success requires more than just copying a formula, it requires identifying a marketing strategy that is unique to your brand’s audience, associated with a great product offering.

At FormuNova, we specialize in helping brands move past imitation to create high-performance product offerings with potential to outperform the current market leaders. Let’s discuss your launch strategy.

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Minimal skincare foam cream and serum drop texture

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Made in USA
Made in USA
Macro close-up of clear cosmetic serum or essence with visible air bubbles. Ideal for beauty branding, cosmetic ads, skincare ingredient design, or clean and minimal product presentations.