K18 Vs Olaplex: Which Cult-Favorite Hair Treatment Is Better?

When it comes to keeping my hair healthy and strong, I am always on the lookout for the best treatments. That’s why I was so excited to discover the world of hair care treatments, more specifically K18 vs Olaplex. These two popular hair treatments have become favorites among hair experts and individuals alike for their ability to repair and rejuvenate damaged hair. The focus of our article will be to explore the differences between K18 vs Olaplex, which will hopefully guide you in finding the perfect treatment suited to your individual hair needs.

As I began my research on the two treatments, I discovered that K18 and Olaplex use different key ingredients and processes to work their magic. K18’s secret weapon is K18PEPTIDE, while Olaplex relies on Bis-Aminopropyl Diglycol Dimaleate. It’s also worth noting that K18 is a leave-in, post-shampoo treatment, whereas Olaplex No.3 is a pre-shampoo treatment meant to be left in for at least ten minutes. But which one is better? That’s a question we will explore throughout the article as we dive deeper into these cult-favorite hair treatments – K18 vs Olaplex.

K18 vs Olaplex: Basics

As a haircare enthusiast, I’ve tried various products to improve the health of my hair. Among the top treatments available in the market today are K18 and Olaplex. Though both products aim to repair hair damage, they work somewhat differently and have varying usage instructions, prices, and benefits.

K18 is best known for its leave-in molecular repair hair mask, which focuses on repairing hair at the molecular level. This bioactive peptide treatment deeply penetrates the hair shaft to restore damaged hair caused by chemical, thermal, or mechanical processes. To use K18, I apply it to freshly shampooed and towel-dried hair, leave it in for about four minutes, and then style as usual. There’s no need to rinse it out.

In contrast, Olaplex features its popular No.3 Hair Perfector, a pre-shampoo treatment that works on a molecular level to strengthen hair bonds and prevent further breakage. As someone who has tried Olaplex No.3, I can attest that it’s designed to be left on for at least 10 minutes before washing it out and using shampoo and conditioner. This treatment is recommended once or twice a week, depending on the level of hair damage.

Regarding pricing, it’s worth noting that K18 is generally more expensive than Olaplex. However, the cost difference may vary depending on where you purchase the products, such as in a salon or through an online retailer.

8Expert Score
K18 Review
  • Noticeably improves hair texture and health
  • Simple, minimalistic, and travel-friendly.
  • Quality and results could justify the cost.
  • Uses bioactive ingredients and is free from parabens, sulfates, and artificial colors.
  • Mild and generally pleasant scent.
  • May not completely repair severely damaged hair
  • Could have a more premium feel for the price point.
  • May not be affordable for everyone.
  • Contains some synthetic ingredients.
  • Might not appeal to everyone due to personal scent preferences.
8.4Expert Score
Olaplex Review
  • Highly effective at repairing damaged hair and preventing further damage.
  • Durable, easy-to-use, and travel-friendly packaging
  • Quality and results can justify the cost for many
  • Innovative ingredients with patented technology. Free from sulfates, phthalates, and parabens.
  • Pleasant, salon-like scent that many users enjoy.
  • May not provide significant benefits for already healthy hair.
  • Design could be considered somewhat plain.
  • May be too expensive for some consumers.
  • Contains some synthetic ingredients.
  • Some may find the scent too strong or not to their liking.

K18 Vs Olaplex: Key Differences

When it comes to hair repair products, K18 and Olaplex are two of the top contenders in the market. In this section, I’ll be sharing my thoughts on the ingredients, price, and other key differences between K18 vs Olaplex.

Ingredients and Technology

Olaplex uses Bis-Aminopropyl Diglycol Dimaleate as its main ingredient, which works to rebuild broken disulfide bonds in the hair. On the other hand, K18 features the K18Peptide (sh-Oligopeptide-78) as its primary ingredient, which focuses on repairing broken keratin chains in the hair. Both of these patented technologies are quite effective in addressing hair damage.

When it comes to amino acids, they play a crucial role in our hair’s health. Amino acids are essential for hair, as they are the building blocks of protein, which makes up a large portion of our hair’s structure. The K18Peptide found in K18 products is a bioactive peptide that incorporates 18 amino acids, giving it the ability to penetrate deep into the hair cortex and repair hair strands from within.

To sum up, both K18 vs Olaplex use innovative and patented technologies which harness the power of Bis-Aminopropyl Diglycol Dimaleate and K18Peptide (sh-Oligopeptide-78), respectively. These key ingredients help address hair damage, with amino acids playing a critical role in the K18Peptide.


When it comes to price, K18 is notably more expensive than Olaplex. A 50ml bottle of K18 hair mask costs around $75, while a 100ml bottle of Olaplex No. 3 is priced at $28. Keep in mind that both products may have different sizes available, and the price may vary depending on where you purchase them. Despite the higher price tag, K18 also offers smaller trial sizes (5ml and 15ml) for those who want to test the product before committing to the full-size version.

Time and Process

The application time for each treatment is different. Olaplex No.3 should be left on the hair for at least ten minutes or longer before rinsing, while K18 only requires four minutes before styling as usual. This difference in application time allows for a more convenient experience with K18, especially for those who may have minimal time for hair care.

For K18, it’s a leave-in treatment that should be applied to damp hair and left for about four minutes before styling as usual. On the other hand, Olaplex No. 3 is a bond builder that requires a slightly more involved process. You apply it to damp hair, comb it through, and let it sit for at least ten minutes before rinsing and following up with shampoo and conditioner.


The effects of an Olaplex treatment in a salon typically last for four to six weeks, contingent upon the state of the hair and its damage. I suggest undergoing three to four sessions at even intervals to achieve optimal results.

As for preserving healthy hair, applying a K18 mask six times in a row followed by once every three to four washes is necessary. Furthermore, the mist-based in-salon treatment can be administered before each chemical treatment.


Incorporating K18 or Olaplex into your hair care routine may depend on the hair damage you’re dealing with and your preferred treatment. Both products are suitable for all hair types but differ in terms of usage.

Daily Upkeep

Olaplex offers a variety of at-home care products that cater to different hair types and requirements. Except for No.1 and No.2, all other products can be integrated into your daily hair-care routine. Meanwhile, you can regularly use the K18 mask as a leave-in-treatment at home. It’s advisable to consult your hair stylist for a personalized recommendation.


In terms of sustainability, K18 has made a strong commitment to reducing waste and plastic in their packaging. Even though it might require a little digging to find the information, their dedication to the environment is commendable.

To summarize the basic differences between these two hair treatments:

  • K18:
    • K18PEPTIDE: Bioactive peptide to repair hair at a molecular level
    • Leave-in formula: Apply to freshly shampooed, towel-dried hair
    • Generally more expensive
  • Olaplex:
    • Bis-Aminopropyl Diglycol Dimaleate: Strengthens hair bonds and prevents breakage
    • Pre-shampoo treatment: Leave on for at least 10 minutes before washing out
    • Typically more affordable

In my experience, both K18 vs Olaplex have proven effective in repairing damaged hair and improving overall hair health. Choosing between these two hair treatments ultimately depends on your specific hair needs, budget, and personal preferences.

Product Offerings and Usage

When it comes to K18 vs Olaplex, both brands have unique product offerings that cater to different hair care needs. Let’s take a closer look at some of their respective products, along with recommendations on how to use them.


  • K18 Peptide Prep Detox Shampoo: This clarifying shampoo effectively removes 99% product buildup, 95% sebum, and 76% copper without stripping your hair. Containing activated charcoal to remove oil and buildup, along with salicylic acid to unclog scalp pores, it’s an excellent shampoo to use before applying K18 hair treatments.
  • K18 Molecular Repair Hair Mask: The star product of the K18 line, this hair mask uses a patented bioactive peptide hair treatment to support and strengthen hair elasticity while repairing damage from various sources like heat styling, chemical treatments, and coloring services. It can be used as a stand-alone treatment or in combination with K18 shampoo.


  • Olaplex No.1: This first step in the Olaplex system is a professional in-salon treatment. It’s mixed with your hair color or lightener for added protection against damage during the coloring process.
  • Olaplex No.2: Another in-salon treatment, No.2 is applied after rinsing out No.1. It continues the bond-repairing process, strengthening and protecting your hair.
  • Olaplex No.3: As a pre-shampoo treatment, you apply this product to damp, towel-dried hair and leave it on for at least 10 minutes before washing it out with your favorite shampoo and conditioner. It provides a regular maintenance solution to keep your hair in good shape and reinforce the bond-repairing benefits of No.1 and No.2.

Now, let’s discuss how to use K18 and Olaplex hair treatments:

  • K18 Molecular Repair Hair Mask: Apply this leave-in treatment to freshly shampooed, towel-dried hair. Allow it to sit for 4 minutes, and style as usual. No need to rinse it out.
  • Olaplex No.3: Apply as a pre-shampoo treatment. Let it sit on your hair for a minimum of 10 minutes, then rinse and continue with your usual shampoo and conditioner routine.

For both K18 vs Olaplex, consistent usage is key to achieve the best results. Choose the right products depending on your hair care needs and never forget to follow the instructions to maintain the efficacy and integrity of these fantastic treatments.

K18 vs Olaplex: Additional Information

When it comes to K18 vs Olaplex hair treatments, there are some extra details that I find essential for potential users to know. Both of these brands offer their products with a focus on repairing damaged hair, but they do have some differing features that may influence your decision.

Firstly, I should mention that both K18 vs Olaplex are cruelty-free, which means they do not involve any animal testing in their product development process. This is an essential consideration for those looking to make ethical and conscientious choices in their beauty routines.

Regarding vegan-friendly products, K18’s leave-in molecular repair hair mask is vegan, meaning it does not contain any animal-derived ingredients. However, be sure to check individual Olaplex products as some might contain animal-derived ingredients.

In my experience, both K18 vs Olaplex treatments proved to be color-safe, meaning they should not interfere with or strip the color of chemically-treated hair. This makes them suitable options for people who have colored hair and want to maintain their hair’s vibrancy while repairing damage.

When it comes to fragrance, I noticed that K18 has a mild scent that is pleasant and not overpowering. Olaplex No.3, on the other hand, carries a slightly stronger fragrance. Depending on your preferences and sensitivities, the fragrances of each product may be a deciding factor for you.

Regarding packaging, both K18 vs Olaplex use plastic containers for their products. While this may be seen as a downside for environmentally conscious individuals, it is wise to check how to recycle each type of packaging in your local area to be sustainable.

Recap – K18 vs Olaplex

In the hair industry, both K18 and Olaplex are known for their ability to help repair and maintain the structural integrity of damaged hair due to everyday wear and tear or chemical treatments. As a quick recap, let’s break down the key differences between these two popular hair care lines.

  • K18 is well-regarded for its K18Peptide, a unique ingredient that helps repair and strengthen hair from the inside out. 
  • Olaplex uses Bis-Aminopropyl Diglycol Dimaleate to treat damaged hair. This bond builder works on a molecular level to restore broken bonds within the hair shaft. 
  • K18 is a leave-in treatment, while Olaplex No.3 is a pre-shampoo treatment
  • K18 is more expensive than Olaplex and offers additional products, such as the Peptide Prep pH Maintenance Shampoo, Molecular Repair treatment for hair repair, and Detox Shampoo for clarifying needs.
  • Olaplex is a 3-step process involving their No.3 Treatment, No.4 Shampoo, and No.5 Conditioner. 
  • Olaplex has a thicker consistency than K18 and is designed to be a pre-shampoo treatment left on for ten minutes before being washed out.
  • K18 involves fewer processes and provides a more convenient experience, especially for those with minimal hair care time. 

With these points in mind, as a consumer, it’s important to consider your hair’s unique needs and preferences when deciding between K18 and Olaplex for hair repair and maintenance.


K18 and Olaplex are effective in fixing damaged hair, regardless of hair type. K18 targets keratin chains and reconstructs the hair from the inside, strengthening the hair shaft’s length and width. On the other hand, Olaplex reconnects the broken disulfide bonds in the hair.

Hence, it’s challenging to determine which treatment is best for your hair. However, if your hair is severely damaged, K18 might be a better choice because it rebuilds the hair structure and doesn’t wash out easily. Hopefully, this K18 vs Olaplex review will help you make an informed decision.

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