L'Oreal Elvive Dream Lengths Frizz Killer Serum Versus Kérastase Nutritive 8H Magic Night Serum Hydrating Treatment

CI 19140 is also known as Tartrazine. Tartrazine is a synthetic dye used in cosmetics, foods, and medicine to add a yellow color.

Tartrazine is created from petroleum and is water-soluble.

Citronellol is used to add fragrance/parfum to a product. It is often derived from plants such as roses. In fact, it can be found in many essential oils including geranium, lavender, neroli, and more. The scent of Citronellol is often described as "fresh, grassy, and citrus-like".

Since the Citronellol molecule is already unstable, Citronellol becomes irritating on the skin when exposed to air.

Coumarins are a group of substances found naturally in plants. There are over 1300 types of coumarins identified. It has a natural vanilla scent.

Coumarin is an identified EU known allergy, meaning it may cause an allergic reaction when applied to the skin.

Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.

Topically, glycerin does several things at once:

Hexyl 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.

We don't have a description for Hydrolyzed Corn Protein yet.

Hydrolyzed Soy Protein is a vegan protein made to mimic hydrolyzed collagen. It is created from soy, or glycine soja.

This ingredient is a humectant, meaning it helps hydrate the skin by binding to water. According to a manufacturer, it is also a great hair conditioner.

This ingredient is a plant-derived protein made by breaking down wheat proteins into smaller amino acids and peptides. It has skin and hair conditioning properties.

People with known wheat allergy or a history of immediate reactions should be cautious with leave-on products containing hydrolyzed wheat proteins.

Hydroxycitronellal is a fragrance created from citronellal. The smell of hydroxycitronellal is often described as "citrus-like" or "melon-like".

Hydroxycitronellal is a known EU allergen and may cause irritation when applied to the skin.

Limonene 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".

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.

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.

Phenoxyethanol 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.

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.