Peptide Skincare & BeautySkin science and ingredient guides

Skin science article

L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus L'Oreal Elvive Total Repair 5 Damage Erasing Balm

L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus L'Oreal Elvive Total Repair 5 Damage Erasing Balm What's inside Benefits Concerns Ingredients Side-by-side Water Isopropyl Myristate Dimethicone Amodimethicone Triethanolamine Phenoxyet

L'Oréal Professionnel Absolut Repair Molecular Repair Leave In Mask Versus L'Oreal Elvive Total Repair 5 Damage Erasing Balm

What's inside

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

Cetearyl Alcohol

Euphorbia Cerifera Cera

Cetyl Esters

Glycerin

Hexyl Cinnamal

Chlorhexidine Dihydrochloride

Benzyl Salicylate

Hydroxypropyltrimonium Hydrolyzed Wheat Protein

Limonene

Amyl Cinnamal

Citronellol

2-Oleamido-1,3-Octadecanediol

CI 19140

CI 15985

Water, Cetearyl Alcohol, Behentrimonium Chloride, Amodimethicone, Euphorbia Cerifera Cera, Cetyl Esters, Glycerin, Isopropyl Alcohol, Parfum, Phenoxyethanol, Trideceth-6, Hydroxypropyl Guar, Arginine, Glutamic Acid, Linalool, Hexyl Cinnamal, Cetrimonium Chloride, Serine, Chlorhexidine Dihydrochloride, Benzyl Salicylate, Hydroxypropyltrimonium Hydrolyzed Wheat Protein, Benzyl Alcohol, Limonene, Amyl Cinnamal, Citronellol, 2-Oleamido-1,3-Octadecanediol, Alpha-Isomethyl Ionone, CI 19140, CI 15985

Alternatives

Ingredients Explained

These ingredients are found in both products.

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

Alpha-Isomethyl Ionone is a fragrance. It can be synthetically created or naturally occurring.

The scent of Alpha-Isomethyl Ionone is described as "flowery" but can also be "woody".

Naturally occurring Alpha-Isomethyl Ionone may be found in Saccharomyces cerevisiae, or the yeast used to make wine and bread.

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.

This water-soluble silicone is used for its hydrating and softening properties. It is used to add a silky feel to skincare products and has great benefits for haircare.

In haircare, this ingredient:

Adds shine

Protects color

Offers thermal protection

Boosts hair strength

Does not build up as easily

Arginine is a semi-essential amino acid. This just means our bodies can product a bit on its own, but sometimes needs a little boost from food sources.

It is a part of your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.

A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.

Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.

One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.

Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.

This ingredient is a preservative and often used for it's anti-static properties. You'll most likely see this ingredient in hair conditioners.

It does not cause irritation or sensitization in leave-on products at 1-5%.

Benzyl Alcohol is an aromatic alcohol with several roles: it's a preservative, solvent, and mild fragrance component with a floral scent.

This ingredient has been deemed safe for use in cosmetic formulations at concentrations up to 5%, and up to 10% in hair dyes. You'll typically see 0.5-2% in most rinse-off or leave-on products.

As a preservative, it works by disrupting the membrane of microbial proteins. This helps keep bacteria and fungi from growing in your products.

The sensitization picture is actually quite assuring as well:of nearly 71,000 patients patch tested with benzyl alcohol, only 0.21% showed a positive reaction with most of them being weakly positive.

This led researchers to conclude that benzyl alcohol cannot be regarded as a significant contact allergen.

It is worth noting this ingredient is classified as one of the EU's regulated fragrance allergens and restricted to 1% in finished products.

Labels must also declare it in concentrations above 0.001% in leave-on products and 0.01% in rinse-off products.

At concentrations around 5%, localized redness and itching can appear as a direct irritant response and not as a true allergic reaction.

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.

Glutamic Acid is an amino acid that is found in all living organisms. Our bodies use this to help nerve cells in the brain communicate with other cells.

In cosmetics, glutamic acid is a famous humectant. It draws water from the air to your skin, keeping your skin hydrated (like hyaluronic acid).

An in-vitro study from 2024 found glutamic acid to play a role in inhibiting inflammation and thus a potential skin-soothing ingredient.

Other studies show it to be have potential wound healing, skin barrier repair, and hair growth properties.

Glutamic acid has poor solubility in water and other solvents.

We don't have a description for Hydroxypropyl Guar yet.

Isopropyl Alcohol is more commonly known as rubbing alcohol. It is most commonly used as a solvent, meaning it helps other ingredients dissolve.

This ingredient is an astringent alcohol. Astringent alcohols may also irritate skin as they high amounts may strip away your skin's natural oils.

Other types of astringent alcohols include:

According to the National Rosacea Society based in the US, you should be mindful of products with these alcohols in the top half of ingredients.

Any type of sanitizing product will have high amounts of alcohol to help kill bacteria and viruses.

Linalool is a fragrance and helps add scent to products. It's derived from common plants such as cinnamon, mint, citrus, and lavender.

Like Limonene, this ingredient oxidizes when exposed to air. Oxidized linalool can cause allergies and skin sensitivity.

This ingredient has a scent that is floral, spicy tropical, and citrus-like.

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.

Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).

It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.

On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.

Another perk of this ingredient is that it stays functional across a wide pH range (3-10).

You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.

Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.

Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.

Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.

Serine is a non-essential amino acid (your body makes it on its own!). It is a major player in your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

Serine is one of your NMF's most abundant components that works as a skin-identical humectant. Its hydroxyl group grabs onto water molecules to boost hydration without any heaviness or occlusion.

Research on a hydrogel with serine confirmed this serine got delivered to your stratum corneum and demonstrated enhanced skin moisturization.

Interestingly serine also helps your skin produce filaggrin, a protein that keeps your skin barrier strong and used to create collagen.

We don't have a description for Trideceth-6 yet.

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!

Similar Comparisons

The reference edit

Ingredients, questions
& further reading.

Connected source records selected through this article’s public topic index.

02

Product index

Related product references

03

Comparison edit

Read side by side