Biolage Scalp Sync Anti-Dandruff Shampoo Versus REDKEN Scalp Relief Dandruff Control Shampoo

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.

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.

Polyquaternium-10 is an ammonium salt of hydroxyethylcellulose. It is a white and granular powder used as a film-former and anti-static agent.

This ingredient is commonly found in hair conditioning products. According to a manufacturer, its positive charge makes it great for absorbing hair proteins. The manufacturer also states this ingredient helps with curl retention.

Propylene Glycol is an odorless, colorless liquid. As a humectant, it helps skin retain moisture. It also aids in delivering active ingredients.

Another role of this ingredient is preventing a product from melting or freezing. Propylene glycol also adds antimicrobrial properties to a product, elongating product lifespan.

Sodium 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 Laureth Sulfate (SLES) is a foaming, cleansing, and emulsifying ingredient. It is created from palm kernel oil or coconut oil. SLES is not the same as sodium lauryl sulfate. It is much milder and less likely to irritate.

SLES helps create foam in personal products. It also prevents ingredients from separating, helping to elongate the shelf life.

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.

Zinc Pyrithione is a preservative. It inhibits the multiplying of fungal and bacterial cells.

You'll most likely find this ingredient in Malassezia treatments. In the US, this ingredient is most common in anti-dandruff shampoos. However, the European Union has prohibited the use of this ingredient starting in 2022.