Estée Lauder Perfectionist Pro Rapid Renewal Retinol Treatment Versus Estée Lauder Perfectionist Pro Serum Rapid Brightening Treatment with Ferment² + Vitamin C

Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

• It is a solvent, meaning that it helps to dissolve other ingredients. This also enhances the absorption of the product into one's skin.
• It is a humectant, which means that it helps attract moisture into the skin.
• It helps improve product application.
• It has mild preservative properties.

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Algae Extract is a confusing name. This is because algae is an informal term for a group of 30,000 aquatic organisms that can photosynthesize.

The term 'algae extract' can refer to any one, or a blend of, the 30,000 types.

Caffeine is most associated with coffee, tea, and cacao. In skincare, it helps with calming inflammation and is rich in antioxidants.

While caffeine is used to treat cellulite and and dark circles, further studies are needed to prove this. It has been believed to help with these skin conditions due to its ability to dilate blood vessels and increase blood flow.

Yeast extract is a silky, clear liquid derived from yeast (usually Saccharomyces cerevisiae or Torula yeast).

This ingredient has plenty of skin benefits:

Tocopheryl Acetate is AKA Vitamin E. It is an antioxidant and protects your skin from free radicals. Free radicals damage the skin by breaking down collagen.

One study found using Tocopheryl Acetate with Vitamin C decreased the number of sunburned cells.

Caprylyl Glycol is a humectant and emollient, meaning it attracts and preserves moisture.

It is a common ingredient in many products, especially those designed to hydrate skin. The primary benefits are retaining moisture, skin softening, and promoting a healthy skin barrier.

Sodium Hyaluronate is hyaluronic acid's salt form. It is commonly derived from the sodium salt of hyaluronic acid.

Like hyaluronic acid, it is great at holding water and acts as a humectant. This makes it a great skin hydrating ingredient.

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.

Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.

In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.

Disodium EDTA plays a role in making products more stable by aiding other preservatives.

It is a chelating agent, meaning it neutralizes metal ions that may be found in a product.

BHT is a synthetic antioxidant and preservative.

As an antioxidant, it helps your body fight off free-radicals. Free-radicals are molecules that may damage your skin cells.

Potassium Sorbate is a preservative used to prevent yeast and mold in products. It is commonly found in both cosmetic and food products.

This ingredient comes from potassium salt derived from sorbic acid. Sorbic acid is a natural antibiotic and effective against fungus.

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.