K18 Leave-In Molecular Repair Hair Mask – 4-Minute Peptide Treatment for Damaged Hair, 15 mL
Leave-In Treatment for Bleach, Color, Chemical and Heat-Damaged Hair
Treat damaged, brittle, dry, or overprocessed hair with the K18 Leave-In Molecular Repair Hair Mask. This concentrated leave-in treatment uses the brand’s patented K18PEPTIDE™ to support the internal structure of hair damaged by bleaching, coloring, chemical services, and repeated heat styling.
Unlike a traditional rinse-out hair mask, K18 is applied to clean, towel-dried hair after shampooing and remains in the hair. The formula requires a full four-minute processing period before combing, applying other products, or styling.
This listing includes one 15 mL / 0.5 fl oz Mini Size pump bottle. Its compact size is suitable for trial use, travel, shorter hairstyles, or adding K18 to an existing treatment routine.
What’s Included
🧴 K18 Leave-In Molecular Repair Hair Mask – 15 mL / 0.5 fl oz
One concentrated leave-in peptide hair treatment in a compact pump bottle.
Because the mini bottle dispenses a smaller amount per pump, K18 recommends using approximately 3–9 mini pumps, depending on hair length, texture, and density.
Important: This listing includes only the 15 mL Mini Size. No additional bottle, shampoo, conditioner, oil, heat protectant, or styling accessory is included.
Why You’ll Love It
⏱️ Four-Minute Leave-In Treatment
The concentrated formula requires only four minutes to process and does not need to be rinsed out.
🧬 Powered by K18PEPTIDE™
Contains a biotech-developed peptide designed to mimic part of the hair’s keratin structure and reconnect damage sites within the hair fiber.
🎨 Designed for Bleach and Color Damage
Suitable for hair affected by highlighting, bleaching, permanent color, lightening, and other salon color services.
🧪 Supports Chemically Treated Hair
Can be incorporated into a care routine for hair exposed to chemical straightening, relaxing, perming, or other professional chemical services.
🔥 Helps Repair Heat-Related Damage
Designed to address existing damage caused by blow-drying, flat ironing, curling, and other repeated heat styling.
🪮 Softening and Detangling Benefits
The lightweight cream formula helps improve softness, smoothness, manageability, and ease of detangling.
🌎 Suitable for All Hair Types
Can be used on straight, wavy, curly, and coily hair, as well as fine, medium, thick, color-treated, or chemically treated strands.
🌱 Vegan and Color-Safe
K18 identifies the formula as vegan, color-safe, and cruelty-free.
👜 Compact 15 mL Bottle
The small pump bottle is convenient for travel, trial use, touch-up routines, or limited storage space.
Product Features
✔ K18 Leave-In Molecular Repair Hair Mask
✔ 15 mL Mini Size
✔ Approximately 0.5 fl oz
✔ Patented K18PEPTIDE™ technology
✔ Four-minute processing time
✔ Leave-in formula
✔ No additional rinsing required
✔ Designed for damaged hair
✔ Suitable for bleach-damaged hair
✔ Suitable for color-treated hair
✔ Suitable for chemically treated hair
✔ Suitable for heat-damaged hair
✔ Helps improve hair strength and elasticity
✔ Helps improve softness and smoothness
✔ Supports easier detangling
✔ Helps improve manageability
✔ Lightweight cream texture
✔ Highly concentrated formula
✔ pH-optimized formula
✔ Suitable for all hair types
✔ Suitable for straight hair
✔ Suitable for wavy hair
✔ Suitable for curly hair
✔ Suitable for coily hair
✔ Vegan formula
✔ Color-safe
✔ Cruelty-free
✔ Compact pump bottle
✔ One 15 mL bottle per package
✔ Intended for adult cosmetic use
How K18PEPTIDE™ Works
Hair is primarily made from keratin proteins arranged in structural chains. Bleaching, coloring, chemical processing, heat styling, and mechanical stress can weaken these structures and reduce the hair’s strength and elasticity.
K18PEPTIDE™, listed in the ingredients as sh-Oligopeptide-78, is a biotech-developed peptide designed to mimic part of the hair’s natural keratin structure.
According to K18, the peptide works within the hair fiber to reconnect damaged polypeptide chains. As these chains are reconnected, associated disulfide bonds are also supported, helping reinforce the hair along its length and width.
The treatment is designed to help damaged hair feel:
🧬 Stronger
🪶 Softer
✨ Smoother
🌀 Bouncier
🪮 More manageable
🌿 More resilient during styling
The term “repair” refers to improvements in the structure, strength, elasticity, and condition of the existing hair fiber. This is a cosmetic treatment and does not affect hair growth or permanently heal the scalp.
Damage from Bleaching and Coloring
Bleaching and permanent coloring can affect the hair’s protein structure and increase porosity, dryness, tangling, and breakage.
The K18 mask is designed to support hair exposed to:
🎨 Permanent hair color
💡 Highlights and lowlights
🤍 Bleaching and lightening
🌈 Fashion-color services
🧪 Color correction
🔁 Repeated salon color treatments
Use the mask for the first four to six shampoos following a color or chemical service, then continue as needed for maintenance.
Damage from Chemical Services
Chemical treatments can alter the internal and external structure of the hair.
The mask can be incorporated into routines for hair exposed to:
🧪 Chemical straightening
〰️ Relaxing services
🌀 Perming treatments
🎨 Bleaching and coloring
💇 Professional salon processing
Follow the instructions provided by the salon professional and the manufacturer of the chemical service.
K18 should not replace required neutralizing, rinsing, or aftercare steps associated with a professional chemical treatment.
Damage from Heat Styling
Frequent exposure to high temperatures can contribute to dryness, brittleness, reduced elasticity, split ends, and breakage.
K18 is designed to repair existing damage associated with:
🔥 Blow-drying
🔥 Flat ironing
🔥 Curling irons
🔥 Hot brushes
🔥 Heated rollers
🔥 Other thermal styling tools
The mask is not identified as a dedicated heat protectant. Apply a separate heat-protection product after the four-minute processing period and before using hot tools.
Immediate and Progressive Treatment
K18 describes the mask as providing immediate and progressive results.
Some users may notice changes in softness, smoothness, or manageability after the first use, while the brand states that many users observe more noticeable results after two or three applications.
K18 recommends using the mask for four to six consecutive shampoos after significant damage, bleaching, coloring, or a chemical service.
After the initial treatment period, use it as needed for maintenance. K18’s guidance suggests maintenance use approximately every three to four washes or whenever the hair requires additional damage support.
Results vary according to hair condition, treatment history, porosity, length, density, texture, and application method.
Scientific Testing Information
K18 states that its repair claims are supported by scientific-technical testing performed on damaged hair fibers and tresses.
According to the brand:
🧬 Improvements in strength and elasticity were observed on bleach-damaged fibers after one four-minute application.
🔥 Reduced breakage was observed on heat-damaged hair tresses after one application.
📈 Progressive reduction in breakage was observed with repeated applications on bleach-damaged hair.
💪 Bleached hair tresses were reported to be two times more resistant to breakage after one application.
Testing was conducted under controlled conditions. Individual consumer results may differ.
Lightweight Cream Formula
The product has a concentrated cream texture designed to spread through damp hair without requiring the amount normally used with a traditional hair mask.
Conditioning ingredients help provide slip, softness, and easier distribution, while the peptide and protein ingredients support the mask’s damage-repair function.
Using too much product can make the hair feel coated or weighed down. Begin with three mini pumps and add more only if sections of the hair have not been covered.
Suitable Hair Types
The K18 Leave-In Molecular Repair Hair Mask can be used on:
🪶 Fine or thin hair
🌿 Medium-density hair
☁️ Thick or coarse hair
➖ Straight hair
🌊 Wavy hair
➰ Curly hair
🌀 Coily hair
🎨 Color-treated hair
🤍 Bleached or highlighted hair
🔥 Heat-damaged hair
🧪 Chemically treated hair
💧 Dry or brittle hair
🪮 Tangled or difficult-to-manage hair
✂️ Hair with visible breakage or split ends
Fine or low-density hair should begin with the smallest recommended amount. Thick, long, curly, coily, or high-density hair may require additional pumps for even distribution.
How to Use
Step 1: Shampoo
Wash the hair thoroughly with shampoo.
If the hair has heavy styling-product, oil, silicone, mineral, or hard-water buildup, K18 recommends using an appropriate clarifying or detox shampoo before the treatment.
Rinse the shampoo completely.
Step 2: Do Not Condition
Skip rinse-out conditioner before applying the K18 mask.
Conditioner can leave a coating on the hair that may interfere with the peptide’s ability to reach the intended areas of the hair fiber.
A conditioner or other leave-in product may be applied after the mask has completed its four-minute processing period if additional conditioning is needed.
Step 3: Towel-Dry Thoroughly
Gently squeeze excess water from the hair and towel-dry until it is damp rather than dripping wet.
Do not rub the hair aggressively with the towel.
Excess water may dilute the mask and make even distribution more difficult.
Step 4: Apply 3–9 Mini Pumps
Begin with approximately three pumps from the 15 mL bottle.
Add more gradually according to hair length and density, using up to nine mini pumps when needed.
The mini bottle dispenses less product per pump than the standard full-size bottle.
Step 5: Distribute from Ends Upward
Apply the mask beginning at the ends, which are often the most damaged and porous areas.
Work upward through the middle lengths and toward the roots.
Distribute the cream evenly with the hands. Do not comb immediately.
Step 6: Wait Four Minutes
Allow the mask to remain undisturbed for a full four minutes.
Do not rinse.
Do not comb, brush, add conditioner, apply styling products, or begin heat styling during the processing period.
Step 7: Style as Usual
After four minutes:
-
Comb or detangle the hair gently.
-
Apply conditioner, leave-in products, hair oil, or styling products if desired.
-
Apply a separate heat protectant before thermal styling.
-
Air-dry, blow-dry, or style as usual.
Mini Pump Guide
🪶 Short or Fine Hair
Begin with approximately three mini pumps.
🌿 Medium-Length or Medium-Density Hair
Use approximately three to six mini pumps.
☁️ Long, Thick, Curly or Coily Hair
Use up to nine mini pumps when needed for complete coverage.
These amounts are starting guidelines. Add more only when necessary to cover missed sections.
Suggested Treatment Schedule
Initial Repair Period
Use after shampooing for four to six consecutive washes.
This schedule is particularly useful after:
🎨 Bleaching or coloring
🧪 Chemical services
🔥 Repeated heat styling
💇 Salon processing
🪮 Noticeable increases in breakage or brittleness
Maintenance Period
After the initial four-to-six-wash period, use the mask every three to four washes or as needed.
Restart the consecutive-use routine after another significant bleaching, coloring, chemical, or high-heat styling period if desired.
Helpful Usage Tips
🫧 Clarify the hair first if it has heavy styling-product, oil, silicone, mineral, or hard-water buildup.
🚫 Do not apply rinse-out conditioner before the mask.
💧 Towel-dry until the hair is damp, not dripping wet.
🧴 Begin with three mini pumps because the formula is highly concentrated.
✋ Emulsify the cream briefly between the palms before distributing it through the hair.
⬆️ Start at the ends and work upward toward the roots.
⏱️ Wait the complete four minutes before combing or applying another product.
🚿 Do not rinse out the mask.
🪮 Detangle only after the processing time is complete.
🔥 Apply a separate heat protectant before blow-drying or using hot tools.
📅 Use consistently for the first four to six shampoos, then transition to maintenance use.
📋 Always check the received packaging for the latest directions and formula information.
What to Avoid
🚫 Do not condition before applying the mask.
🚫 Do not apply it to heavily coated or unwashed hair.
🚫 Do not apply it to dripping-wet hair.
🚫 Do not rinse it out after four minutes.
🚫 Do not comb or brush during the four-minute processing period.
🚫 Do not add styling products until the four minutes are complete.
🚫 Do not assume that applying more product will produce better results.
🚫 Do not rely on this mask as a substitute for heat protectant.
🚫 Do not use it to replace required salon aftercare or medical treatment.
Care & Storage
Close the pump bottle securely after each use.
Store upright in a cool, dry location away from direct sunlight, excessive heat, and moisture.
Keep the pump opening clean and free from dried product.
Do not dilute the formula or add water to the bottle.
Do not transfer the mask into an unclean container.
Use the product before the expiration or period-after-opening date shown on the packaging, when provided.
The 15 mL bottle is compact and travel-friendly, but customers should still follow applicable airline and transportation requirements.
Important Safety Information
For external use only.
Avoid direct contact with the eyes. If contact occurs, rinse thoroughly with clean water.
Do not use on severely irritated, broken, or injured skin.
Discontinue use if persistent redness, itching, burning, swelling, or another adverse reaction occurs.
Keep out of reach of unsupervised children.
Do not ingest.
The formula contains fragrance and fragrance allergens, including geraniol, linalool, hexyl cinnamal, benzyl alcohol, and amyl salicylate.
The formula also contains hydrolyzed wheat protein and hydrolyzed wheat starch. Review the ingredient list before use if you have known wheat, fragrance, or cosmetic sensitivities.
Perform a patch test before full use if you are sensitive to new hair-care products.
This is a cosmetic treatment for the existing hair fiber. It is not intended to diagnose, treat, cure, or prevent hair loss, scalp disease, or another medical condition.
Product Specifications
Brand: K18
Product Name: Leave-In Molecular Repair Hair Mask
Product Type: Leave-in peptide hair treatment
Size: 15 mL / approximately 0.5 fl oz
Number of Items: 1
Item Form: Concentrated cream
Processing Time: 4 minutes
Rinse Required: No
Application: Clean, damp, towel-dried hair
Recommended Amount: Approximately 3–9 mini pumps
Recommended Hair Types: All hair types
Hair Concerns: Bleach damage, color damage, chemical damage, heat damage, breakage, brittleness, dryness, and reduced elasticity
Featured Technology: Patented K18PEPTIDE™
INCI Peptide Name: sh-Oligopeptide-78
Formula pH: Approximately 5.0–6.0
Color-Safe: Yes
Vegan: Yes
Cruelty-Free: Yes
Contains Fragrance: Yes
Contains Hydrolyzed Wheat Ingredients: Yes
Recommended Use: Adult cosmetic hair care
Amazon ASIN: B09HR5KSR8
Item Model Number: K18-31007
Listed Product Dimensions: Approximately 1.37 × 1.37 × 3.18 inches
Listed Item Weight: Approximately 1.76 ounces
Product measurements and weight are based on the referenced retail listing and may vary slightly according to packaging or shipping preparation.
Ingredients
Water (Aqua) (Eau), Alcohol Denat., Propylene Glycol, Cetearyl Alcohol, Dicaprylyl Ether, Cetyl Esters, Behentrimonium Chloride, Polysorbate 20, sh-Oligopeptide-78, Hydrolyzed Wheat Protein, Hydrolyzed Wheat Starch, Isopropyl Alcohol, Tocopherol, Phenoxyethanol, Potassium Sorbate, Citric Acid, Fragrance (Parfum), Geraniol, Linalool, Hexyl Cinnamal, Benzyl Alcohol, Amyl Salicylate, Benzaldehyde.
Ingredient lists may be updated by the manufacturer. Customers should review the label on the received product for the most current ingredients and safety information.
Key Formula Components
🧬 sh-Oligopeptide-78
The ingredient name used for the patented K18PEPTIDE™ technology.
🌾 Hydrolyzed Wheat Protein and Wheat Starch
Protein-derived ingredients that support the hair-conditioning and strengthening properties of the formula.
🪶 Cetearyl Alcohol and Cetyl Esters
Conditioning and texture-supporting ingredients that help the hair feel soft and manageable.
🪮 Behentrimonium Chloride
A conditioning ingredient that provides slip and supports easier detangling.
✨ Tocopherol
A form of vitamin E used as an antioxidant within the formula.
⚗️ Citric Acid
Helps maintain the product’s intended pH.
🌸 Fragrance
Provides the product’s scent. The formula contains individually listed fragrance allergens.
Package Includes
📦 1 × K18 Leave-In Molecular Repair Hair Mask, 15 mL / 0.5 fl oz
Shampoo, conditioner, clarifying treatment, hair oil, heat protectant, combs, brushes, towels, and styling accessories are not included.
Product Highlights
🧬 Patented K18PEPTIDE™ formula
⏱️ Four-minute processing time
🚿 No rinsing required
🎨 Designed for bleach and color damage
🧪 Suitable for chemically treated hair
🔥 Supports repair of existing heat damage
🪮 Softening and detangling benefits
🌎 Suitable for all hair types
🌱 Vegan and color-safe formula
🐰 Cruelty-free
👜 Compact 15 mL pump bottle
📦 One bottle per order
Frequently Asked Questions
What size is included?
This listing includes one 15 mL / approximately 0.5 fl oz Mini Size bottle.
Does the package include more than one bottle?
No. Each order includes one 15 mL bottle.
Should this mask be rinsed out?
No. It is a leave-in treatment and should not be rinsed out.
Should conditioner be used before K18?
No. Shampoo the hair and skip conditioner before applying K18. Conditioner may leave a coating that interferes with effective peptide penetration.
Can conditioner be used afterward?
Yes. After the four-minute processing period, a conditioner, leave-in treatment, oil, or styling product may be applied if needed.
Does the hair need to be wet?
Apply the mask to clean, damp, thoroughly towel-dried hair. It should not be applied to dripping-wet hair.
Can it be applied to dry hair?
K18 recommends applying the mask to clean, damp hair for proper distribution and performance.
How many pumps should be used?
Use approximately 3–9 mini pumps, depending on hair length, density, and texture. Begin with three pumps and add more only when needed.
Why does the mini bottle require several pumps?
The 15 mL bottle has a small pump that dispenses less product with each press. Three mini pumps do not equal three pumps from a full-size K18 bottle.
How long should it remain on the hair?
Wait at least four full minutes before combing, applying other products, or styling. Do not rinse afterward.
Can it be left on overnight?
The product is designed to remain in the hair, but its required active processing period is four minutes. There is no need to use it as a separate overnight rinse-out mask.
How frequently should it be used?
Use it for four to six consecutive shampoos during the initial repair period. Afterward, use every three to four washes or as needed for maintenance.
Can it be used on fine hair?
Yes. Fine hair should begin with approximately three mini pumps to avoid a coated or weighed-down feel.
Can it be used on curly or coily hair?
Yes. The formula is suitable for straight, wavy, curly, and coily hair.
Is it suitable for color-treated hair?
Yes. K18 identifies the mask as color-safe and designed for damage associated with bleaching and coloring.
Does it contain protein?
Yes. The formula contains hydrolyzed wheat protein, hydrolyzed wheat starch, and the peptide sh-Oligopeptide-78.
Does it contain fragrance?
Yes. The formula contains fragrance and individually listed fragrance allergens.
Is it vegan?
Yes. K18 identifies the formula as vegan.
Is it cruelty-free?
Yes. K18 identifies the product as cruelty-free.
Does it provide heat protection?
The mask is designed to repair existing heat-related damage, but it is not identified as a dedicated heat protectant. Apply a separate heat-protection product after the four-minute wait and before hot tools.
Will it permanently repair split ends?
It can improve strength, smoothness, and the appearance of damaged ends, but no cosmetic product can permanently fuse severely split ends. Trimming may still be necessary.
Will it make hair grow faster?
No. The mask treats the existing hair fiber and is not a hair-growth treatment.
Can it treat hair loss or scalp problems?
No. It is a cosmetic hair treatment and is not intended to treat hair loss, scalp disease, or another medical condition.
Should the received label be checked before use?
Yes. Manufacturers may update formulas or packaging. Review the received bottle for the most current ingredients, directions, and safety information.
Support stronger, softer, smoother, and more resilient-looking hair with a concentrated four-minute leave-in treatment powered by K18PEPTIDE™. 🧬⏱️✨
