How Do Moisturizers Work?

Happy smiling woman applying moisturizer to face
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Moisturizing is such a key part of any skin care routine, with most people owning several different moisturizers.

While this may be a product that you use on a daily basis, have you ever wondered how a moisturizer actually works?

It’s actually pretty impressive…

The Role of a Moisturizer

Let’s begin by taking a look at why you even need to be using a moisturizer in the first place.

Your skin consists of three main layers:

  • Epidermis – the outer layer of your skin
  • Dermis – the middle layer of your skin
  • Hypodermis – the lowest and deepest layer of your skin, which includes the subcutaneous tissue

layers of the skin

Your blood vessels are what carry natural moisture to your skin. However, these blood vessels only reach the dermis, meaning that it is only the middle layer of your skin that receives this moisture.

Once there, the moisture from your dermis slowly travels upwards to the outer layer of your skin, before evaporating into the air.

The air is constantly pulling moisture out of your skin, but you are likely to only really notice this in especially dry conditions. Dry air means that even more water will be evaporating out of your skin, which is why many people often experience flaking and cracking during the dry winter months. This often remedies itself in the spring, once the humidity in the air starts to rise again.

So, what does a moisturizer actually do?

It has a couple of key jobs:

  • Restoring moisture in the outer layer of the skin
  • Trapping moisture in the skin and preventing it from evaporating

In order to do this, a moisturizer needs to contain at least one of the following ingredient groups…


Humectants are ingredients with quite a unique chemical structure.

This enables them to attract moisture, whether this may be from the air, from other skin care products, or from other cells in your body.

Once the moisture has been drawn to the humectant, the humectant then locks this in, providing it to your skin as and when your skin needs it.

As a result of this, a humectant can have quite an immediate hydrating effect on your skin, plumping your skin cells up and giving you an overall brighter and fresher complexion.

Sounds good, right?

As always, there’s a downside that you need to know about…

When the air is especially dry, it does not contain enough moisture for the humectant to draw in. However, the chemical structure of a humectant means that it will always seek out water. When it can’t get this from the air, it instead takes it from the deeper layers of your skin.

This is not something you want, as it leaves those younger skin cells lacking in vital hydration. You may not be able to see the results of this at first, as skin cells slowly rise to the surface as they mature, but it could mean that your skin ends up even drier than ever.

This doesn’t mean that you need to stay away from humectants in severely dry conditions…

Instead, make sure that your humectants are paired with occlusive ingredients.


Occlusives are where moisturizers first began, with some of the very first moisturizing products containing petroleum jelly as their main moisturizing ingredient.

What do occlusives actually do?

Imagine a pot of boiling water…

Without a lid over the top, the water will simply bubble over and evaporate. However, when you put a lid on, this keeps all of the water trapped inside the pot.

Well, occlusives are basically the lid.

They work by forming a physical barrier over the surface of the skin, which then prevents the water from within the skin from evaporating. This is why occlusives work so well with humectants – the humectants draw in the moisture and then the occlusives trap it there.

Occlusives are effective at keeping the skin hydrated for quite a while.

So, what’s the downside to occlusives?

The fact that many of them can end up causing breakouts.


Due to the way in which they form a film over the surface of the skin, trapping everything in beneath. Some occlusives just work too well, meaning that they trap in dead skin cells and bacteria too. The combination of both of these, along with product residue, is the perfect recipe for a breakout.


The best analogy to describe an emollient would be to think of the outer layer of your skin as a brick wall.

The bricks themselves would be your dead skin cells, and the cement that holds the bricks together is made up of a mix of fats and proteins. This wall is basically your body’s barrier between itself and the environment around it, along with the toxins, chemicals, pollutants and more that the environment contains.

When the air is dry, the “cement” cracks and falls apart, leaving gaps in your skin’s surface.

While humectants and occlusives remain on the outermost surface of your skin, emollients penetrate into those little gaps, filling them up and giving you back a smoother complexion.

Some emollients also double up as an occlusive, which is why this ingredient category has become more prevalent in newer moisturizer formulas.

Combining Humectants, Occlusives and Emollients

Wondering if humectants, occlusives and emollients can be combined?

Of course! In fact, that’s exactly what makes for a great moisturizer.

Each of those ingredient types work hand-in-hand together when it comes to the roles that a moisturizer performs, meaning that you ideally want to be seeing at least one ingredient from each group in your moisturizer.

Why don’t all moisturizers contain all three ingredient groups?

Because everybody’s skin varies in terms of needs. For example, those with oily skin would want a moisturizer with less occlusives, as these can often lead to breakouts. However, those with severely dry skin would need an emollient consisting heavily of occlusives.

This is why it is important to understand the differences between each group. This enables you to decide exactly what your skin would benefit from, before looking for a moisturizer that meets those requirements.

Recognizing Humectants, Occlusives and Emollients on an Ingredient List 

Now that you know how each ingredient group works, you need to also know how to recognize humectants, occlusives and emollients on an ingredients list, since they won’t be listed as such.

Instead, you would need to look out for specific ingredients.

There are many different humectants, occlusives and emollients out there, and it is always worth experimenting with different ones to find what works best for your skin.

However, here are some of the best…

The Best Humectants

If you want to make sure that your moisturizer contains some quality humectants, here are some ingredients to look out for:

  • Hyaluronic Acidalthough the skin produces hyaluronic acid itself, the rate at which it does so declines drastically with age. Hyaluronic acid is a humectant that can hold up to 1000 times its weight in water, making it a superstar at hydrating the skin 
  • Glycerin – another ingredient that occurs naturally in the body, glycerin is quite an inexpensive humectant, making this a popular one to incorporate into skin care products
  • Aloe Vera – the hydrating qualities of aloe vera are largely due to the fact that this ingredient acts as a humectant, while also providing powerful anti-inflammatory and skin-soothing properties 
  • Sodium PCA – found naturally on the skin, sodium PCA is 1.5 times more powerful at drawing in moisture than glycerin, but does tend to be quite a pricey ingredient
  • Seaweed and Algae – these humectants are so hydrating, and also soothe the skin while providing it with vital nutrients. Seaweed and algae are both also commonly used for their anti-aging properties
  • Hydrolyzed Wheat or Rice Proteins – these proteins contain an amino acid called glutamine, which is able to attract and retain moisture
  • Honey – not only is honey a fantastic humectant, but it also contains so many proteins, vitamins, minerals, amino acids and enzymes. It is also a good source of alpha hydroxy acids, giving it a mild exfoliating effect 

Humectants are ingredients that all skin types can benefit from, meaning that everybody’s moisturizer should contain at least one of the above.

The Best Occlusives

If occlusives are the ingredient group that you want your moisturizer to be heavy in, here are a few of the top occlusives to seek out:

  • Cocoa Butter – not only is cocoa butter so richly nourishing, but it also makes for a great occlusive. Another bonus is that cocoa butter is a great source of vitamin E, which is not only a skin-protector but also boosts the production of collagen in the skin
  • Allantoin – this botanical extract forms a healthy barrier over the surface of the skin, encouraging cell regeneration and skin healing at the same time
  • Beeswax – this ingredient has the added benefit of being packed with fatty acids and other skin-beneficial nutrients, while also soothing and calming the skin at the same time
  • Vegetable Waxes – if you are looking for a plant-based alternative to beeswax, carnauba wax and candelilla wax are good options
  • Plant Butters and Oils – plant butters and oils that are high in oleic acid are great at providing occlusive benefits. Examples would include shea butter, olive oil, macadamia oil, avocado oil and castor oil

Two of the most popular occlusives in skin care haven’t been mentioned above…

These would be petroleum jelly and mineral oil.

Wondering what the deal is with those two?

They are effective at creating a seal over the skin, and they are both also quite inexpensive ingredients. However, they do have quite a negative environmental impact, and, due to the fact that they work so well at forming a barrier over the skin, they can often lead to breakouts since the pores aren’t able to breathe properly.

The Best Emollients

If you want to ensure that your moisturizer has been formulated with some beneficial emollients, these are some of the best ingredients to look out for:

  • Shea and Cocoa Butter – although both of these ingredients have been listed above as occlusives, they also double up as an effective emollient, giving you the best of both worlds
  • Plant Oils – plant oils are another ingredient group that work as both occlusives and emollients. They are also a fantastic source of antioxidants, making them great anti-aging ingredients
  • Squalene – an anti-aging and anti-inflammatory ingredient that also helps to re-balance the skin’s natural oil production  
  • Triglycerides – these compounds can come from a variety of natural sources, and are known to be an effective skin-replenishing emollient thanks to their high fatty acid content
  • Stearates – naturally found in the human body, stearates not only provide a product with emollient properties, but also help with stabilizing ingredients and conditioning the skin

If your skin is dry or dehydrated, emollients are something that you definitely want to be focusing on. 

Choosing a Moisturizer

Now that you know about the three main ingredient groups that make up a moisturizer, you are so much better equipped when it comes to choosing the best moisturizer for your skin.

Woman shopping for cosmetics and reading labels

Don’t forget…

A moisturizer can also contain many other beneficial ingredients, so you need to always keep your skin type in mind.

For example, those with aging concerns should opt for a moisturizer packed with antioxidants and ceramides, whereas those with oily skin should seek out a moisturizer with anti-inflammatory ingredients that help to prevent pore blockages

Everybody’s skin is individual, so it may take some trial and error before you find a moisturizer that works well for you.

Just about everybody out there would benefit from using a moisturizer, making this a product that you should already be using on a daily basis. If you have been noticing that your moisturizer isn’t having the effect that you would want it to, it may be time to take a look out there and see if there are any better options for you.

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