An honest review of K18's new shampoos

I am a regular, fairly devout user of K18’s leave-in treatment. I use it on quiet Sunday evenings in between oiling parts of my body and staring off into the middle ground as I grieve the end of my weekend.

Mondays are my meeting-heavy day, so I figure that if this is the one day a week I turn my Zoom camera on to let my boss, David, see how my bangs are growing out, I might as well look presentable. For me, I’ve found that K18’s mask does in four minutes what I’ve spent probably hundreds of dollars seeking in lesser bond-building treatments. It takes my dry, brittle ends and makes them supple again without weighing my pelo down. Plus, it's nice to have things in your beauty arsenal that you can just count on. I regularly recommend it to my loved ones and tell my enemies: “Meh, save your money. You'll like OGX better!”

Now there’s some good news to balance out the general evil quality of that last sentence: K18 just launched two new shampoos! It's a fascinating move for two reasons.

It’s two shampoos. “Wouldn’t one cannibalize the other?” people who work in the beauty industry and are comfortable using industry jargon would think.
They launched two shampoos and no conditioners? What’s that all about?

Valid concerns. I’ll address both points over the course of this article. First: each shampoo serves a purpose. The Peptide Prep pH Maintainance Shampoo is for daily use. If you’re one of those people who insist on washing their hair every day but feel guilty about it, this one’s for you. The pH in the name references the slightly acidic (4.5–5.5 pH) nature of the formula, which is designed to stop hair from drying out.

The Peptide Prep Detox Shampoo is the second shampoo in the lineup. How the Detox Shampoo differs from the pH Shampoo is that this is meant to clarify. If I use the pH shampoo Monday–Friday, I’ll use the Detox Shampoo on Sundays. It is also more ideal for those who are less frequent washers to make sure you’re starting each wash cycle over with a clean canvas. The formula includes activated charcoal to absorb 99% of product build-up, 95% of sebum, and 75% of copper deposits. It also features salicylic acid to clear oil buildup in your hair follicles in the same way that it can help clear out blackheads.

Both shampoos “microdose” (their words — not mine — even though I wish I wrote that copy) with its secret sauce: K18PEPTIDE. Put simply, this shampoo includes the same active ingredient from their Leave-in Molecular Repair Mask that has a 4.7-star rating based on 5924 reviews on the K18 site. Damn, that’s a lot of reviews!

What is the K18PEPTIDE?

It’s K18’s proprietary compound of amino acids that pose as keratin chains within your hair — seamlessly integrating into the strands. These chains give your hair strength and elasticity and are compromised during any sort of damage, like chemical treatments, heat styling, or even UV rays. They repair your hair from the inside out.

They both are low-to-no lather and rinse out clean without stripping or leaving behind residue. Both are color-safe, as well.

What kind of hair does it work for?

Any hair that wishes it felt virgin again. That includes (but is not limited to): bleached, dyed, permed, natural, straightened, blowdried, curly, straight, wavy, thin, coarse, highlighted, balayaged, toned, double-processed, dry, oily, brittle, damaged, and teased hair.

Which one should I get?

Depends. If you’re an everyday washer: get the pH Shampoo. If you’re a weekly-or-so washer, get the detox. If you’re in the middle, like me, you might benefit from both.

So, why didn’t they release a conditioner?

I can’t speak for them, but here’s my best guess: because you don’t really need one after using it. It’s not that this system is anything like a 2-in-1 shampoo/conditioner hybrid. They aren’t suddenly trying to corner the market that Head & Shoulders already has called home.

The formulation just eradicates the need for a follow-up conditioner. After washing, my hair is left more manageable, so there’s no reason for me to add anything else to my head. Softer, noticeably more pliable. Even my curls seem to spring back to life, even if they were looking a little pitiful before.

To think that my dream conditioner has been shampoo this whole time. Well, I’ll be.