Kiehl's Vital Skin-Strengthening Hyaluronic Acid Super Serum Versus Caudalie Vinopure Natural Salicylic Acid Pore Minimizing Serum

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.

Pelargonium Graveolens Flower Oil is the pressed oil of the Rose Geranium plant. It is volatile, meaning it evaporates off the skin.

Fragrant components of Rose Geranium include citronellol and geraniol. These may cause allergies and skin-sensitivity. We recommend speaking with a professional if you have any concerns.

Rosmarinus Officinalis Leaf Oil is oil expressed from the leaves of the rosemary plant.

Rosemary Leaf Oil is a fragrance and helps give your product a scent. If you are sensitive to irritating fragrances, this one contains camphor. Camphor has been found to irritate skin.

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.

Tocopherol (also known as Vitamin E) is a common antioxidant used to help protect the skin from free-radicals and strengthen the skin barrier. It's also fat soluble - this means our skin is great at absorbing it.

Vitamin E also helps keep your natural skin lipids healthy. Your lipid skin barrier naturally consists of lipids, ceramides, and fatty acids. Vitamin E offers extra protection for your skin’s lipid barrier, keeping your skin healthy and nourished.

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.

Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.

On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.