Types of Moisturizers: Making Sense of Moisturizing Ingredients

Formulate user Aricia has a moisturizer question:

I feel like I'm always being told that this ingredient is super good and moisturizing for my skin, that that other ingredient is also good and will plump my skin up, et cetera. There's always a new moisturizer that I'm being told I should buy a product that's formulated with it because x new ingredient is just such a game changer. Like I feel like hyaluronic acid is a big one right now, but I also keep finding myself wanting to buy stuff that's formulated with argan oil since I've heard that's so good for my skin. And I'm sure that in a few years there will be another ingredient that I'm told is the best ever for moisturizing my skin, and then I'll be told to go buy products with that ingredient as well. So what's the actual difference between all of these different moisturizer ingredients? Do they work differently and is there a type of moisturizing ingredient that's actually the best? Maybe all these ingredients work equally well and I've just been wasting my money. PS - do I actually need to moisturize, or is all of this made up?

Thanks for your questions, Aricia! We appreciate you reaching out.

All moisturizing ingredients fall into one of three categories - humectant, emollient, and occlusive. Typically, a commercially sold moisturizer will have a combination of the three, since none of them work perfectly alone. So, nope, there's probably not a single wonder ingredient that will prove to be the best moisturizing agent ever for your skin - several moisturizing ingredients work together in each product to produce the final results. And yes, you probably do need to moisturize - more on that below.

To answer your question further, we spoke to three beauty experts: board-certified dermatologist Dr. Kemunto Mokaya (Dr. Kemmy), board-certified aesthetic dermatologist Dr. Sam El mais, and Certified Physician Assistant and founder of Element Medical Aesthetics Merry Thornton.

Let's start with humectants - what do they do and how do they work?

Dr. Kemmy: When you think of humectants, you should think of water! Humectants attract water to the top layer of the skin (stratum corneum). They draw water into the stratum corneum either by pulling it from the deeper layers of the skin or by grabbing it from the environment. Humectants are great for all skin types, from oily to dry skin.

Dr. El mais: I am sure you have heard about the amazing benefits of including products with hyaluronic acid, urea, amino acids, aloe vera, and peptides into your skincare routine. These are all examples of humectants. Humectants pull water into the skin and then hold it there. Humectants tend to be lighter in texture and absorb quickly, making them ideal for hydrating oily or acne-prone skin.

Merry Thornton: Humectants, aka hydrators, bind water to the skin. These products are good for dehydrated skin. How do you know if you have dehydrated skin? It can look dull, lackluster and wrinkly. These ingredients get water into the skin cells to make them look more plump.

Common examples of humectants: hyaluronic acid, amino acids, aloe vera, peptides, glycerin, alpha hydroxy acids, lactic acid, and sorbitol.

How about emollients?

Dr. Kemmy: When you think of emollients, you should think of oil. Emollients get in between the skin cells to help fill the cracks and gaps in the skin. They repair or improve the barrier created by the stratum corneum and give the skin a soft, smooth feel. Emollients are found in most types of moisturizers and can be used on all skin types.

Dr. El mais: I recommend emollients for those with irritated or inflamed skin. While an emollient may have some occlusive properties, its primary role is to soften the skin. It is an oily material that fills the gaps between dead skin cells, resulting in a smooth skin surface. People with acne-prone skin should use non-comedogenic emollients to prevent breakouts and clogged pores.

Merry Thornton: Emollients, which typically come in the form of creams, lotions, and ointments, lock and seal moisture into the skin to improve the stratum corneum. The stratum corneum contains fatty acids, ceramides, and cholesterol and is responsible for keeping the good stuff in and the bad stuff out.

Common examples of emollients: Lipids, ceramides, coconut oil, avocado oil, jojoba oil. grapeseed oil, castor oil, argan oil, and linoleic acid.

And occlusives?

Dr. Kemmy: They form a thin, oily layer over the skin that prevents water loss from the skin. Occlusives work best when they are applied to damp skin because they trap the moisture inside. Occlusives tend to be heavy, waxy, and greasy in order to form that water-resistant barrier. Products with occlusives come as balms, butters, and salves. Occlusives are great for people with dry skin and conditions like eczema and psoriasis. They are also great for the lips because your lips do not contain sebaceous glands to moisturize themselves.

Dr. El mais: Occlusives, like emollients, will lock moisture into your skin. While emollients work best for oily skin, occlusives are heavier and more effective for drier skin. Occlusives protect the skin from external irritants and water loss.

Merry Thornton: Occlusives serve as a physical barrier to prevent water loss and protect the skin from irritants and environmental damage. They tend to feel heavier and are good for very dry skin.

Examples of occlusive ingredients are petrolatum, waxes, lanolin shea butter, petroleum jelly, and silicones like dimethicone.

Are multiple types of moisturizers included in the same products?

Dr. Kemmy: While it is useful to know the different types of moisturizers and what they do, in real life, most moisturizers will contain a mixture of emollients, humectants, and occlusives. Pay attention to the thickness and formulation of the moisturizer e.g. ointments are greasy (and are usually predominantly made of occlusives), lotions are light and water-based (tend to contain many humectants), and creams are in between. Facial oils are predominantly made from emollients.

And does everyone really need to moisturize?

Dr. Kemmy: People of all skin types need to moisturize their skin to keep it healthy and hydrated. People with dry skin need to moisturize more.

Merry Thornton: Everyone should moisturize because the skin barrier needs lipids and ceramides to stay healthy and youthful. Even people with oily skin will benefit from moisturizing because oil does not equal hydration. Prolonged dehydration of the skin can accelerate aging. For those with oily skin, use non-comedogenic humectants with lighter formulations such as lotions.