K18PEPTIDE™ is a biotech-developed peptide that mimics hair's structure to reverse damage by reconnecting polypeptide chains and disulfide bonds broken during bleaching, color and chemical services + heat*.

pH-optimized (5.0-6.0) to help minimize cuticle swelling + put hair proteins in their most resilient state.

Cream format enables easy, lightweight application across all hair types, with detangling and softening benefits.

Vegan, color-safe, cruelty-free.

Takes damage repair further – reconnects both polypeptide chains (and as a result, also reconnects disulfide bonds) for strength along the length + width of the hair - offering comprehensive, lasting damage repair.

Restores hair from even extreme damage - by working at the innermost layer of the hair, core strength and elasticity are renewed for strong, smooth, bouncy hair.

Delivers immediate and lasting results – hair is repaired from the first use and lasts past your next wash, for ongoing reparative benefits.

Simplified repair - convenient, leave-in formula works in just 4 minutes, with no extra rinse required.

Works on all hair types – because K18PEPTIDE™ works on a molecular level (where all hair is the same), this product is effective on all hair types.

Shampoo, do not condition. Towel-dry thoroughly.

Apply 1-3 pumps of K18 leave-in molecular repair hair mask based on your length and density, starting at the ends and working up towards the roots.

Let sit for 4 minutes. Do not rinse out.

Comb, add product + style as usual. Use for 4-6 washes post-salon service, then as needed.

• DO clarify before K18 if you’re a heavy product user (demineralize for mineral + metal buildup).
• DO apply on clean, damp hair.
• DO wait the full 4 minutes before combing or styling.
• DO add whatever styling products you love after the 4 minutes.
• DO use for 4-6 shampoos consecutively for progressive results.
• DON'T use conditioner before applying K18 Mask (you can apply after the 4 min but most find they don’t need it).
• DON'T overdo it—less is more.
• DON'T rinse it out.

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.

Do I rinse it out or leave it in?

Leave it in — that's K18's direction and it's the one I'd follow. Apply to clean, towel-dried hair, wait the four minutes, then style as normal. If you don't like the feel of a leave-in you can rinse and condition afterwards; the peptide is already in the hair by then, so you won't undo the repair. It just isn't necessary.

Is K18 right for my hair type?

Yes. This is one of the few products I'd put on everyone — every hair type, every texture, colored or virgin. Bleach and color do the most damage, so that's where you'll see the biggest change, but heat, hard water and everyday wear break the same bonds in any head of hair.

Why doesn't my hair feel instantly transformed?

Because this isn't a surface product and it isn't an instant fix. K18 works inside the hair, reconnecting bonds broken by bleach, color and heat. That's a real, permanent structural repair — but permanent and instant aren't the same thing. Use it for four to six consecutive washes after a service and judge it then, not after one.

If it repairs the hair, why do I still need other products?

Because internal and external repair are two different jobs, and I recommend both. K18 works internally — rebuilding the structure inside the strand. It doesn't smooth the cuticle or seal the outside. That's external work, and it's what Sebastian NO.BREAKER Leave-In Cream and the Wella Ultimate Repair Protective 5-in-1 Leave-In are for. They're designed to be used together with K18, and that's exactly what I do in my chair — one working inside the hair, one working on the outside.

Do I use conditioner before it?

No. Shampoo, skip the conditioner, towel-dry thoroughly, then apply. Conditioner beforehand coats the hair and gets in the way of the peptide. Afterwards is fine if you want it.

How much do I use, and which size?

One to three pumps depending on length and density — less is more, and overdoing it won't speed anything up. The 15ml is a genuine trial size; the 50ml is what most people settle on; the 150ml only makes sense once you know it's part of your routine.

Is it safe on color?

Yes — vegan, color-safe, cruelty-free, and pH-optimized between 5.0 and 6.0, which is the range that keeps the cuticle from swelling. It's designed to be used straight after color and bleach services.