Peptide repair for bleached, coloured and heat-damaged hair

K18

K18 Biomimetic Hairscience is built on one patented ingredient, the K18PEPTIDE™. It is a biomimetic peptide designed to reach the inner cortex of the hair and reconnect the broken keratin chains and bonds that bleach, colour, chemical services and hot tools leave behind. The brand was founded in San Francisco in 2020 and is now part of Unilever Prestige.

The hero is the Leave-In Molecular Repair Hair Mask: shampoo, skip conditioner, towel-dry, apply one to three pumps and wait four minutes. Around it sit three wash lines: Peptide Prep Detox for a weekly reset that clears buildup and hard-water metals, Damage Shield for pH-balanced daily washing and conditioning, and TripleBright for blondes whose brass keeps coming back.

To finish, the Weightless Molecular Repair Hair Oil tames frizz and split ends, HeatBounce protects against heat up to 450°F, AstroLift builds volume in fine hair and AirWash refreshes second-day roots without a white cast. FutureIQ is a nightly scalp serum for early shedding and first greys. Our five buying guides walk through each choice.
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Find your K18 range

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K18 PRO Pre-Service Molecular Repair Mist — 300 ml trigger-spray bottle, front labelK18 PRO Pre-Service Molecular Repair Mist — 300 ml trigger-spray bottle, white background
K18

K18 PRO Pre-Service Molecular Repair Mist – Professional Back-Bar Treatment for Chemical Services

$98.00
$98.00
K18 PRO Repair Starter Kit — kit — 300 ml PRO mist and 150 ml PRO mask with the service-kit boxK18 PRO Repair Starter Kit — 150 ml PRO mask included in the kit
K18

K18 PRO Repair Starter Kit – Professional Molecular Repair Mist + Mask Service Set

$189.00
$189.00
K18 Detox & Repair At-Home Duo — 53 ml detox shampoo and 50 ml mask with the at-home duo boxK18 Detox & Repair At-Home Duo — 53 ml PEPTIDE PREP detox shampoo included in the duo
K18

K18 Detox & Repair At-Home Duo – Peptide Prep Shampoo 53 ml + Leave-In Repair Mask 50 ml

$63.00
$63.00
K18 HeatBounce Leave-In Conditioning Heat Protectant — 118 ml bottle, front labelK18 HeatBounce Leave-In Conditioning Heat Protectant — 237 ml salon-size bottle, front label
K18

K18 HeatBounce Leave-In Conditioning Heat Protectant – Protection up to 450°F

$6.00
$6.00
K18 AstroLift Reparative Volume Spray — 118 ml spray bottle, front labelK18 AstroLift Reparative Volume Spray — 47 ml spray bottle, front label
K18

K18 AstroLift Reparative Volume Spray – Lightweight, Buildable Volume for Fine Hair

$6.00
$6.00
K18 Weightless Molecular Repair Hair Oil — 30 ml dropper bottle, front labelK18 Weightless Molecular Repair Hair Oil — 10 ml mini beside 30 ml full size
K18

K18 Weightless Molecular Repair Hair Oil – Frizz Control, Shine & Heat Protection

$21.00
$21.00
K18 AirWash Non-Aerosol Dry Shampoo — 4 oz (118 ml) spray bottle, front labelK18 AirWash Non-Aerosol Dry Shampoo — 4 oz bottle with cap removed, floating studio shot
K18

K18 AirWash Non-Aerosol Dry Shampoo – Absorbs Oil & Eliminates Odour for Up to 3 Days

$19.00
$19.00
K18 Leave-In Molecular Repair Hair Mask — 50 ml pump bottle, front labelK18 Leave-In Molecular Repair Hair Mask — 15 ml mini pump bottle, front label
K18

K18 Leave-In Molecular Repair Hair Mask – 4-Minute Peptide Treatment for Damaged Hair

$6.00
$6.00
K18 TripleBright Purple Shampoo — 125 ml foam-pump bottle, front labelK18 TripleBright Purple Shampoo — 125 ml bottle with cap removed, white background
K18

K18 TripleBright Purple Shampoo – Triple-Action Brass Defense for Blonde & Lightened Hair

$30.00
$30.00
K18 Damage Shield Protective Conditioner — 250 ml bottle, front labelK18 Damage Shield Protective Conditioner — 473 ml jumbo pump bottle, front label
K18

K18 Damage Shield Protective Conditioner – Weightless Detangling & Daily Damage Defense

$11.00
$11.00
K18 Damage Shield Protective Shampoo + Conditioner Duo — 250 ml shampoo in the 250 ml duoK18 Damage Shield Protective Shampoo + Conditioner Duo — 473 ml jumbo shampoo in the 473 ml duo
K18

K18 Damage Shield Protective Shampoo + Conditioner Duo – Matched Daily Wash & Care

$58.00
$58.00
K18 Damage Shield Protective Shampoo — 250 ml bottle, front labelK18 Damage Shield Protective Shampoo — 473 ml jumbo pump bottle, front label
K18

K18 Damage Shield Protective Shampoo – pH-Optimized, Colour-Safe Daily Cleanse

$11.00
$11.00
K18 FutureIQ Nightly Biomimetic Scalp Serum — 90 ml dropper bottle, white backgroundK18 FutureIQ Nightly Biomimetic Scalp Serum — 90 ml dropper bottle, studio shot with glass DNA-helix props
K18

K18 FutureIQ Nightly Biomimetic Scalp Serum – Reduces Shedding & Supports Scalp Health 90 ml

$90.00
$90.00
K18 Peptide Prep Detox Clarifying Shampoo — 250 ml bottle, front labelK18 Peptide Prep Detox Clarifying Shampoo — 473 ml jumbo pump bottle, front label
K18

K18 Peptide Prep Detox Clarifying Shampoo – Removes Buildup, Oil & Hard-Water Metals

$11.00
$11.00

How to choose

Repair

Leave-In Molecular Repair Mask on shampooed, unconditioned, towel-dried hair. Wait 4 minutes. Do not rinse.

Wash

Damage Shield every wash. Peptide Prep Detox once a week. TripleBright 1 to 2 times a week for blondes.

Protect and style

HeatBounce before heat, the oil for frizz, AstroLift for volume, AirWash between washes.

Scalp

FutureIQ nightly for early shedding, density and first greys.

Explore the guides

Your questions, answered

How do I use the K18 Leave-In Molecular Repair Mask?
Shampoo, but do not condition. Towel-dry well, then apply 1 to 3 pumps from the ends up toward the roots. Leave it on for 4 minutes, do not rinse, then style as usual. K18 recommends it for 4 to 6 washes after a colour or lightening service, then as needed. A conditioner applied first coats the hair and gets in the peptide’s way.
Can I use conditioner with K18?
Not before the mask. On mask days, shampoo and go straight to the mask. On other days, use the Damage Shield Protective Conditioner (or your usual conditioner) as normal. If you also use the Weightless Hair Oil, apply the mask first, wait 4 minutes, then the oil.
Which K18 shampoo should I buy?
Damage Shield Protective Shampoo is the everyday wash for damaged or colour-treated hair. Peptide Prep Detox is a weekly clarifying shampoo for buildup, hard water and swimming, and the best wash before the mask. TripleBright is a purple foam shampoo for brassy blonde, grey or silver hair, used 1 to 2 times a week.
How is K18 different from Olaplex?
Both target damage inside the hair, but in different ways. Olaplex uses a patented bond-building ingredient to relink disulfide bonds and its No.3 is a rinse-out pre-shampoo treatment. K18 uses a peptide that, according to the brand, reconnects broken keratin chains as well as disulfide bonds, and its mask is a 4-minute leave-in. Our comparison guide covers which suits your hair.
Why is K18 expensive, and how long does a bottle last?
The 50 ml mask is $76.79, but you use 1 to 3 pumps, and only on mask days, so it lasts months for most lengths. Try the 5 ml ($7.15) or 15 ml ($29.65) first, or start with the Detox + Repair At-Home Duo ($86.08), which pairs a 53 ml detox shampoo with the full 50 ml mask.
Is K18 safe for colour-treated and bleached hair?
Yes. The mask, Damage Shield and Peptide Prep are colour-safe, and the mask is designed for bleached, coloured and chemically treated hair. TripleBright deposits violet pigment on purpose; leave it on 1 to 3 minutes, not longer, on very light blonde.
Are the PRO Pre-Service Mist and PRO Repair Starter Kit for home use?
No. They are back-bar products for stylists, used before and after lightening, colour and chemical services. For home care, use the Leave-In Molecular Repair Mask in 5, 15 or 50 ml.
Does FutureIQ regrow hair?
FutureIQ is a cosmetic nightly scalp serum, not a drug. In K18’s own 12-week study users saw up to 19,000 more hairs, 87% showed more density and 70% showed fewer greys. Use it every night for at least 12 weeks before judging, and see a doctor about sudden or patchy hair loss.