ISDIN Fusion Water Urban SPF 30 Versus Hello Sunday The One That’s a Serum - Face Drops SPF 45

Hydroxyacetophenone is antioxidant with skin conditioning and soothing properties. It also boosts the efficiency of preservatives.

Though naturally occuring in Norwegian spruce needles, this ingredient is usually synthetically created.

Octocrylene protects skin from sun damage. It absorbs UV-B with peak absorption of 304 nm. It is a common sunscreen ingredient and often paired with avobenzone, a UVA filter. This is because octocrylene stabilizes other sunscreen ingredients by protecting them from degradation when exposed to sunlight. Octocrylene is a photostable ingredient and loses about 10% of SPF in 95 minutes.

Octocrylene also acts as an emollient, meaning it helps skin retain moisture and softens skin. It is oil-soluble and hydrophobic, enhancing water-resistant properties in a product.

This ingredient is more commonly known as Ensulizole, a chemical sunscreen ingredient.

Ensulizole mainly protects UV-B (290-340 nm) but offers a little UV-A (320-400 nm) protection. It is often paired with less photo-stable sunscreen ingredients due to its photo-stability.

Polysorbate 60 is used to help stabilize products. It is a surfactant and emulsifier. These properties help keep ingredients together in a product. Surfactants help reduce surface tension between ingredients with different states, such as liquids and solids. Emulsifiers help prevent oils and waters from separating.

Polysorbate 60 is sorbitol-based and created from the ethoxylation of sorbitan. Ethoxylation is a chemical reaction used to add ethylene oxide. Sorbitan is a the dehydrated version of sorbitol, a sugar found in fruits.

Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.

In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.

Tocopherol is a fat-soluble antioxidant known as Vitamin E.

You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.

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.