Peptide Skincare & BeautySkin science and ingredient guides

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L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus K18 Hair PEPTIDE PREP™ pH Maintenance Shampoo

L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus K18 Hair PEPTIDE PREP™ pH Maintenance Shampoo What's inside Key Ingredients No key ingredients Benefits Concerns Ingredients Side-by-side Water Isopropyl Myristate Dimethicone Amodimeth

L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus K18 Hair PEPTIDE PREP™ pH Maintenance Shampoo

What's inside

Key Ingredients

No key ingredients

Benefits

Concerns

Ingredients Side-by-side

Water

Isopropyl Myristate

Dimethicone

Amodimethicone

Triethanolamine

Phenoxyethanol

Carbomer

Polyquaternium-4

Potato Starch Modified

Hydroxypropyl Guar

Behentrimonium Chloride

Arginine

Trideceth-6

Isopropyl Alcohol

Cetrimonium Chloride

Linalool

Glycine

Serine

Tyrosine

Citric Acid

Glutamic Acid

Coumarin

Benzyl Alcohol

Benzyl Benzoate

Alpha-Isomethyl Ionone

Parfum

Water, Isopropyl Myristate, Dimethicone, Amodimethicone, Triethanolamine, Phenoxyethanol, Carbomer, Polyquaternium-4, Potato Starch Modified, Hydroxypropyl Guar, Behentrimonium Chloride, Arginine, Trideceth-6, Isopropyl Alcohol, Cetrimonium Chloride, Linalool, Glycine, Serine, Tyrosine, Citric Acid, Glutamic Acid, Coumarin, Benzyl Alcohol, Benzyl Benzoate, Alpha-Isomethyl Ionone, Parfum

Sodium C14-16 Olefin Sulfonate

Cocamidopropyl Betaine

Sodium Methyl 2-Sulfolaurate

Sodium Lauryl Sulfoacetate

Sh-Oligopeptide-78

Panthenol

Glycerin

Sodium Phytate

Guar Hydroxypropyltrimonium Chloride

Disodium 2-Sulfolaurate

Caprylyl Glycol

Caprylhydroxamic Acid

Benzoic Acid

Sodium Hydroxide

Limonene

Water, Sodium C14-16 Olefin Sulfonate, Cocamidopropyl Betaine, Sodium Methyl 2-Sulfolaurate, Sodium Lauryl Sulfoacetate, Sh-Oligopeptide-78, Panthenol, Glycerin, Sodium Phytate, Guar Hydroxypropyltrimonium Chloride, Disodium 2-Sulfolaurate, Caprylyl Glycol, Caprylhydroxamic Acid, Benzoic Acid, Citric Acid, Sodium Hydroxide, Parfum, Limonene

Alternatives

Ingredients Explained

These ingredients are found in both products.

Ingredients higher up in an ingredient list are typically present in a larger amount.

Citric Acid is an alpha hydroxy acid (AHA) naturally found in citrus fruits like oranges, lemons, and limes.

Like other AHAs, citric acid can exfoliate skin by breaking down the bonds that hold dead skin cells together. This helps reveal smoother and brighter skin underneath.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Rosacea skin has a lower threshold for acids generally, with 62.5% of rosacea subjects in one study reacting to lactic acid in a sting test. This is why we mark citric acid as a potential rosacea trigger.

However, this ingredient shows up as a pH adjuster or chelator at roughly 0.1-1% in many products. These low levels are unlikely to be an issue for rosacea skin and becomes a potential trigger at exfoliating concentrations (20%). Because everybody's skin is unique, we recommend a patch test if you are unsure.

Parfum 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.

Water. 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. Remember to stay hydrated!

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