Peter Thomas Roth FIRMx Collagen Serum Versus Kate Somerville KateCeuticals Firming Serum

Glycerin is already naturally found in your skin. It helps moisturize and protect your skin.

A study from 2016 found glycerin to be more effective as a humectant than AHAs and hyaluronic acid.

This synthetic peptide is created from lysine, valine, and palmitic acid.

According to the manufacturer, in-vitro studies show tissue growth and collagen synthesis. Another in-vivo study found 60 volunteers saw a significant reduction in wrinkles after 84 days.

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.

Citric Acid is an AHA derived from citrus fruits (think oranges, lemons, and limes!).

As an AHA, Citric Acid removes the top layer of skin cells from the newer layer of skin underneath. This helps skin to remove dark spots and even out skin tone.

Polysorbate 20 is made by combining ethoxylation of sorbitan, ethylene oxide, and lauric acid. It is a mild cleansing agent, surfactant, and emulsifier.

As a surfactant, it helps collect dirt and oils for washing. Emulsifiers prevent oils and water from separating.

Polysorbate 80 is a surfactant and emulsifier. It is used to keep ingredients together, and prevent oils and waters from separating.

It is made from polyethoxylated sorbitan and oleic acid. This ingredient can be found in cosmetics, foods, and medicine. It is water-soluble.

Sorbitan Isostearate is an emulsifer and cleaning agent. It is created from isostearic acid and sorbitol.

As an emulsifier, Sorbitan Isostearate prevents oils and water from separating.

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.

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.

Isohexadecane is added to enhance texture, emulsify, and to help cleanse. It is an isoparrafin. It is a component of petrolatum.

Due to its large size, Isohexadecane is not absorbed by the skin. Instead, it sits on top and acts as an emollient. Emollients help keep your skin soft and smooth by trapping moisture within.

Ethylhexylglycerin (we can't pronounce this either) is commonly used as a preservative and skin softener. It is derived from glyceryl.

You might see Ethylhexylglycerin often paired with other preservatives such as phenoxyethanol. Ethylhexylglycerin has been found to increase the effectiveness of these other preservatives.

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.