Kiehl's Ultra Facial Cream SPF 30 Versus Kiehl's Ultra Light Daily UV Defense Aqua Gel SPF 50 PA++++ - UK

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.

Myristic Acid is a saturated fatty acid. It is naturally found in milk fat. Other sources include palm oil, coconut oil, and butter fat.

Myristic Acid is an emulsifer and cleanser. As an emulsifer, it stabilizes a product by preventing ingredients from separating. Myristic Acid helps clean your skin by acting as a surfactant. It tends to gather oil and dirt on your skin to be easily rinsed away.

Palmitic Acid is a fatty acid naturally found in our skin and in many plant and animal sources. In cosmetics, it is usually derived from palm oil. It serves many purposes in skincare, acting as a cleanser, emollient, and emulsifier.

As an emollient, palmitic acid helps soften and smooth the skin by preventing water loss. In cleansers, it helps remove oil and dirt while creating foam.

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.

Stearic Acid is a fatty acid. It is an emollient, emulsifier, and texture enhancer.

As an emollient, stearic acid helps soften skin. It aids the skin's protective barrier by preventing water loss. It also provides a gentle cleansing effect without stripping away natural oils.

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.