Who really understands what their favorite beauty products are composed of?Sure, there is an ingredient list on the package that tells you exactly what is in the bottle, but do you really know what the ingredients are and what they do?

I often get asked what consumers should look for when purchasing a good moisturizer or anti-aging product and my answer is always the same: The list of moisturizers and anti-aging ingredients is too long for me to list every potential ingredient. There are just way too many!

However, there are quite a few commonly used ingredients that you may have seen before without really knowing why they are being used and how they benefit you. My goal is to help shed a little light and broaden your ingredient horizon by sharing with you why we, cosmetic chemists, formulate with certain ingredients.

1. Humectants: Ingredients that draw in water from their surroundings. Humectants promote hydration because they create a moisture barrier on the surface of the skin. In high humidity areas, humectants draw water from the atmosphere but when the humidity is low, the humectant can pull water from within the skin increasing water loss leading to drier skin.

Common humectants: glycerin, sorbitol, hyaluronic acid, panthenol, butylene glycol

2. Occlusives: A term for ingredients that form a barrier (like a shield) on the surface of the skin to prevent moisture from escaping (the technical phrase is reducing transepidermal water loss, or TEWL). Essentially they trap water in the skin and work in tandem with humectants to increase improve skin moisturization.

Common occlusives: petrolatum, dimethicone, cocoa butter, beeswax, mineral oil, lanolin, squalene

READ MORE: Anti-Aging Products for Dry Skin

3. Antioxidants: A group of ingredients that reduce free radicals and their damage on the skin. These ingredients can be natural or synthetic and work well when used in combination. There are also antioxidants that help protect the ingredients in the product from degrading. These offer no true skin benefits.

Common antioxidants for skin benefits: superoxide dismustase, tocopherol, glutathione, alpha lipoic acid, resveratrol, grapeseed extract, coenzyme Q10, green tea

READ MORE: What’s a Serum?

4. Anti-inflammatory: Ingredients that reduce inflammation and mitigate the inflammatory responses (redness, swelling, pain, itching).

Common anti-inflammatories: bisabolol, allantoin, sea whip extract, aloe, dipotassium glycyrrhizinate, Beta glucan, calendula

READ MORE: The Science of Inflammation

5. Peptides: Chains of amino acids (less than 50) that help regulate many biological functions by interacting with cells. Synthetic peptides can mimic those naturally occurring in the body to assist with various functions like cell communications and hormone activity.

Common peptides: palmitoyl oligopeptide, palmitoyl tetrapeptide-7, hexapeptide-8, acteyl octapeptide-3