L'Oreal Elvive 450 Heat Slayer Dream Lengths Heat Protector Pre-Iron Serum Leave-In Versus Ouai Leave In Conditioner
What's inside
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Skin ConditioningDimethicone
EmollientStearyl Alcohol
EmollientBehentrimonium Chloride
PreservativePhenoxyethanol
PreservativePolysorbate 20
EmulsifyingTrideceth-9
EmulsifyingPg-Amodimethicone
Parfum
MaskingIsopropyl Alcohol
SolventPPG-5-Ceteth-20
EmulsifyingLaureth-23
CleansingLaureth-4
EmulsifyingCamelina Sativa Seed Oil
Skin ConditioningXylose
HumectantHexyl Cinnamal
PerfumingTrideceth-12
EmulsifyingArginine
MaskingGlutamic Acid
HumectantSerine
MaskingSalicylic Acid
MaskingLinalool
PerfumingBenzyl Salicylate
PerfumingLimonene
PerfumingBenzyl Alcohol
PerfumingCoumarin
PerfumingWater, Dimethicone, Stearyl Alcohol, Behentrimonium Chloride, Phenoxyethanol, Polysorbate 20, Trideceth-9, Pg-Amodimethicone, Parfum, Isopropyl Alcohol, PPG-5-Ceteth-20, Laureth-23, Laureth-4, Camelina Sativa Seed Oil, Xylose, Hexyl Cinnamal, Trideceth-12, Arginine, Glutamic Acid, Serine, Salicylic Acid, Linalool, Benzyl Salicylate, Limonene, Benzyl Alcohol, Coumarin
Water
Skin ConditioningDimethicone
EmollientCetearyl Alcohol
EmollientParfum
MaskingQuaternium-91
Adansonia Digitata Seed Oil
EmollientArgania Spinosa Kernel Oil
EmollientOenothera Biennis Oil
EmollientTocopheryl Acetate
AntioxidantHydrolyzed Rhodophyceae Extract
Tamarindus Indica Extract
SmoothingPanthenol
Skin ConditioningArginine
MaskingAspartic Acid
MaskingPCA
HumectantGlycine
BufferingAlanine
MaskingSerine
MaskingValine
MaskingIsoleucine
Skin ConditioningProline
Skin ConditioningThreonine
Histidine
HumectantPhenylalanine
MaskingSodium Hyaluronate
HumectantBrassica Campestris/Aleurites Fordi Oil Copolymer
Skin ConditioningCetrimonium Chloride
AntimicrobialGlycerin
HumectantBehentrimonium Chloride
PreservativeMyristyl Myristate
EmollientSilicone Quaternium-16
Skin ConditioningLeuconostoc/Radish Root Ferment Filtrate
AntimicrobialButylene Glycol
HumectantUndeceth-11
EmollientButyloctanol
HumectantGuar Hydroxypropyltrimonium Chloride
Skin ConditioningUndeceth-5
EmulsifyingSilicone Quaternium-8
3-O-Ethyl Ascorbic Acid
Skin ConditioningSodium PCA
HumectantSodium Lactate
BufferingDisodium EDTA
Citric Acid
BufferingAcetic Acid
BufferingTrideceth-10
CleansingTocopherol
AntioxidantIodopropynyl Butylcarbamate
PreservativePhenoxyethanol
PreservativeBenzyl Salicylate
PerfumingCitronellol
PerfumingGeraniol
PerfumingGeranyl Acetate
PerfumingHexamethylindanopyran
MaskingLinalool
PerfumingRose Ketones
PerfumingWater, Dimethicone, Cetearyl Alcohol, Parfum, Quaternium-91, Adansonia Digitata Seed Oil, Argania Spinosa Kernel Oil, Oenothera Biennis Oil, Tocopheryl Acetate, Hydrolyzed Rhodophyceae Extract, Tamarindus Indica Extract, Panthenol, Arginine, Aspartic Acid, PCA, Glycine, Alanine, Serine, Valine, Isoleucine, Proline, Threonine, Histidine, Phenylalanine, Sodium Hyaluronate, Brassica Campestris/Aleurites Fordi Oil Copolymer, Cetrimonium Chloride, Glycerin, Behentrimonium Chloride, Myristyl Myristate, Silicone Quaternium-16, Leuconostoc/Radish Root Ferment Filtrate, Butylene Glycol, Undeceth-11, Butyloctanol, Guar Hydroxypropyltrimonium Chloride, Undeceth-5, Silicone Quaternium-8, 3-O-Ethyl Ascorbic Acid, Sodium PCA, Sodium Lactate, Disodium EDTA, Citric Acid, Acetic Acid, Trideceth-10, Tocopherol, Iodopropynyl Butylcarbamate, Phenoxyethanol, Benzyl Salicylate, Citronellol, Geraniol, Geranyl Acetate, Hexamethylindanopyran, Linalool, Rose Ketones
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
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.
Learn more about ArginineThis 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 Salicylate is a solvent and fragrance additive. It is an ester of benzyl alcohol and salicylic acid. This ingredient can be naturally found in some plants and plant extracts.
In fragrances, Benzyl Salicylate may be a solvent or a fragrance component. In synthetic musk scents, it is used as a solvent. For floral fragrances such as lilac and jasmine, it is used as a fragrance component. The natural scent of Benzyl Salicylate is described as "lightly-sweet, slightly balsamic".
While Benzyl Salicylate has been associated with contact dermatitis and allergies, emerging studies show it may not be caused by this ingredient alone.
However, this ingredient is often used with fragrances and other components that may cause allergies. It is still listed as a known allergen in the EU. We recommend speaking with a professional if you have concerns.
Another study from 2021 shows Benzyl Salicylate may have anti-inflammatory properties.
Learn more about Benzyl SalicylateDimethicone is a type of synthetic silicone created from natural materials such as quartz. It is also known as polydimethylsiloxane.
What it does:
Dimethicone comes in different viscosities:
Depending on the viscosity, dimethicone has different properties.
Ingredients lists don't always show which type is used, so we recommend reaching out to the brand if you have questions about the viscosity.
This ingredient is unlikely to cause irritation because it does not get absorbed into skin. However, people with silicone allergies should be careful about using this ingredient.
Note: Dimethicone may contribute to pilling. This is because it is not oil or water soluble, so pilling may occur when layered with products. When mixed with heavy oils in a formula, the outcome is also quite greasy.
Learn more about DimethiconeLinalool 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.
Learn more about LinaloolParfum 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 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.
Learn more about PhenoxyethanolSerine 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.
Learn more about SerineWater. 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!
Learn more about Water