Olaplex No.5 Bond Maintenance Conditioner Versus Olaplex Nº.9 Bond Protector Nourishing Hair Serum
Updated on May 21, 2025
Overview
What they are
These products are both vegan, cruelty-free, and reef safe . They have a total of 12 ingredients in common
Cool Features
They both contain hyaluronic acid
Suited For
They're both likely to be good for dry skin, sensitive skin, scar healing and dark spots
Free From
They both do not contain any harsh alcohols, parabens or sulfates
What's Inside
They both contain common allergens and fragrances
We independently verify ingredients, and our claims are backed by peer-reviewed research. Spot a product that needs an update? Let us know.
Ingredient Info
Olaplex No.5 Bond Maintenance Conditioner 75 ingredients
Olaplex Nº.9 Bond Protector Nourishing Hair Serum 31 ingredients
What's inside (and what isn't)
What's inside (and what isn't)
At a glance
Click on any of the items below to learn more
Olaplex No.5 Bond Maintenance Conditioner 75 ingredients
Olaplex Nº.9 Bond Protector Nourishing Hair Serum 31 ingredients
Key Ingredients
Benefits
Concerns
Benefits
Concerns
Ingredients Side-by-side
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
We don't have a description for Bis-Aminopropyl Diglycol Dimaleate yet.
This ingredient is a preservative, antimicrobial, and emulsifier. It is often used in cosmetics for its ability to cleanse, condition, and reduce static.
Cetrimonium chloride is a quaternary ammonium salt, meaning it has a water-soluble structure.
Citral is a fragrance and used to add a lemon-like scent to products. It is both naturally found in plants and created synthetically. In plants, it is commonly occurring in lemon myrtle, lemongrass, lemon tea-tree, lemon verbena, and other citruses.
The EU mandates Citral be listed separately as a fragrance. It is a known allergen and may cause contact dermatitis. Citral can also used as a masking ingredient.
The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.
The term 'citral' is a collective term for two geometric isomers: geranial/Citral A and neral/Citral B.
Learn more about CitralCitric Acid is an AHA derived from citrus fruits (think oranges, lemons, and limes!).
As an AHA, Citric Acid removes the top layer of skin cells from the newer layer of skin underneath. This helps skin to remove dark spots and even out skin tone.
If you spot Citric Acid near the end of an ingredient list, it's likely there as a pH adjuster rather than an active ingredient.
Read more about some other popular AHA's here:
Learn more about Citric AcidHexyl Cinnamal is a fragrance ingredient with a similar scent to jasmine. It can be naturally found in chamomile essential oil.
This ingredient is a known EU allergen and may sensitize the skin. The EU requires this ingredient to be listed separately on an ingredients list.
Hexyl Cinnamal is not water soluble but is soluble in oils.
Learn more about Hexyl CinnamalLimonene is a fragrance that adds scent and taste to a formulation.
It's found in the peel oil of citrus fruits and other plants such as lavender and eucalyptus. The scent of limonene is generally described as "sweet citrus".
Limonene acts as an antioxidant, meaning it helps neutralize free radicals.
When exposed to air, oxidized limonene may sensitize the skin. Because of this, limonene is often avoided by people with sensitive skin.
The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.
Learn more about LimonenePanthenol is a common ingredient that helps hydrate and soothe the skin. It is found naturally in our skin and hair.
There are two forms of panthenol: D and L.
D-panthenol is also known as dexpanthenol. Most cosmetics use dexpanthenol or a mixture of D and L-panthenol.
Panthenol is famous due to its ability to go deeper into the skin's layers. Using this ingredient has numerous pros (and no cons):
Like hyaluronic acid, panthenol is a humectant. Humectants are able to bind and hold large amounts of water to keep skin hydrated.
This ingredient works well for wound healing. It works by increasing tissue in the wound and helps close open wounds.
Once oxidized, panthenol converts to pantothenic acid. Panthothenic acid is found in all living cells.
This ingredient is also referred to as pro-vitamin B5.
Learn more about PanthenolParfum is a catch-all term for an ingredient or more that is used to give a scent to products.
Also called "fragrance", this ingredient can be a blend of hundreds of chemicals or plant oils. This means every product with "fragrance" or "parfum" in the ingredients list is a different mixture.
For instance, Habanolide is a proprietary trade name for a specific aroma chemical. When used as a fragrance ingredient in cosmetics, most aroma chemicals fall under the broad labeling category of “FRAGRANCE” or “PARFUM” according to EU and US regulations.
The term 'parfum' or 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term.
For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance by INCI standards.
One example is Calendula flower extract. Calendula is an essential oil that still imparts a scent or 'fragrance'.
Depending on the blend, the ingredients in the mixture can cause allergies and sensitivities on the skin. Some ingredients that are known EU allergens include linalool and citronellol.
Parfum can also be used to mask or cover an unpleasant scent.
The bottom line is: not all fragrances/parfum/ingredients are created equally. If you are worried about fragrances, we recommend taking a closer look at an ingredient. And of course, we always recommend speaking with a professional.
Learn more about ParfumPhenoxyethanol is a preservative that has germicide, antimicrobial, and aromatic properties. Studies show that phenoxyethanol can prevent microbial growth. By itself, it has a scent that is similar to that of a rose.
It's often used in formulations along with Caprylyl Glycol to preserve the shelf life of products.
Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.
It’s often used to:
Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.
Learn more about PropanediolSodium Benzoate is a preservative. It's used in both cosmetic and food products to inhibit the growth of mold and bacteria. It is typically produced synthetically.
Both the US FDA and EU Health Committee have approved the use of sodium benzoate. In the US, levels of 0.1% (of the total product) are allowed.
Sodium benzoate works as a preservative by inhibiting the growth of bacteria inside of cells. It prevents the cell from fermenting a type of sugar using an enzyme called phosphofructokinase.
It is the salt of benzoic acid. Foods containing sodium benzoate include soda, salad dressings, condiments, fruit juices, wines, and snack foods.
Studies for using ascorbic acid and sodium benzoate in cosmetics are lacking, especially in skincare routines with multiple steps.
We always recommend speaking with a professional, such as a dermatologist, if you have any concerns.
Learn more about Sodium BenzoateWater. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Stay hydrated!
Learn more about WaterIngredient Ratings
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When to use
Olaplex No.5 Bond Maintenance Conditioner 75 ingredients
Olaplex Nº.9 Bond Protector Nourishing Hair Serum 31 ingredients

Reviews
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