K18

What is K18 and how does it work

K18 products are formulated around a bio-active peptide designed to reconnect broken keratin chains in the hair's cortex. This is different from traditional conditioning ingredients, which mostly smooth the hair's outer layer without repairing internal structure. Because of this, K18 is often marketed as a treatment for chemically or heat-damaged hair rather than a general softening or shine product. Most of the range is meant to be layered into an existing routine: a repairing shampoo or mask first, followed by a conditioner, oil or styling product depending on your needs. The leave-in formulas typically need only a few minutes of contact time and are rinsed out or left in depending on the product. K18 does not replace a trim for split ends, and results depend on how damaged the hair already is, so very brittle or chemically compromised hair may need repeated use before you see a clear difference.

Leave-In Molecular Repair Hair Mask: the core repair step

The Leave-In Molecular Repair Hair Mask Restores damaged hair in just 4 minutes and is the product most people start with when trying K18. It's a lightweight leave-in, not a heavy rinse-out mask, so it works well on fine hair that would otherwise feel weighed down by a traditional mask. Apply it to damp hair after shampooing, distribute evenly and style as usual; there's no need to rinse it out. It's particularly suited to hair that has been through bleaching, keratin treatments or frequent heat styling. On very oily scalps, keep the product to mid-lengths and ends rather than the roots.

Damage Shield Shampoo and Conditioner: a repair-focused cleansing routine

The Damage Shield Shampoo & Conditioner duo is designed to clean and condition hair without stripping it further, which matters if your hair is already fragile from colour or heat damage. The Damage Shield Shampoo is gentle enough for regular use, and the Damage Shield Conditioner follows up to detangle and add slip. Together they form a good everyday base before adding the Leave-In Molecular Repair Hair Mask as a targeted step. If your scalp needs a deeper cleanse first, the Detox Shampoo can be used occasionally to remove buildup from styling products before switching back to the Damage Shield routine.

Styling and heat protection

Astrolift Reparative Volume Spray adds lift at the root while offering some repair benefit, making it useful for fine or flat hair that still needs damage support. Heat Bounce is aimed at protecting hair from styling tools while adding bounce to the finish, so it's worth using before blow-drying or curling. Neither product replaces a dedicated heat protectant if you're using very high temperatures regularly, so check the label for heat tolerance before styling.

At-home kits for a salon-style routine

The At-Home Salon Blowout Kit and the Prep + Repair Duo for Home Use bundle several steps together, which is convenient if you're new to the brand or want to try the full routine without buying each product separately. These kits generally combine a cleansing and repair step with a styling or finishing product. They suit anyone who wants a consistent routine without having to work out the right order or combination of products themselves.

Colour care and scalp-focused options

Defense Purple Shampoo is meant for blonde, grey or lightened hair that needs to counter brassy or yellow tones between salon visits; it's a toning shampoo rather than a repair treatment, so it's usually used alongside, not instead of, the Damage Shield or Leave-In products. Airwash Dry Shampoo can extend time between washes for those trying to reduce heat and water exposure on damaged hair. Neither of these targets internal hair repair, so pair them with the Molecular Repair Hair Mask or Hair Oil if damage is the main concern.

Finishing products: oil and serum

Molecular Repair Hair Oil is a lightweight finishing oil that adds shine and smooths flyaways without weighing hair down, making it a good last step after the Leave-In Molecular Repair Hair Mask. FutureIQ Serum is positioned as a more advanced repair serum for hair that needs ongoing support beyond the basic routine. Both are optional additions rather than essentials, and how often you need them depends on hair porosity and how much heat styling you do.

Popular products

K18 - Leave-In Molecular Repair Hair Mask - 5 ml > K18 - Leave-In Molecular Repair Hair Mask - Herstelt beschadigd haar in slechts 4 minuten - 50 ml > K18 - Leave-In Molecular Repair Hair Mask - 15 ml >

Frequently asked questions