How do moisturisers help your skin?When your skin barrier is functioning optimally, it can effectively block out allergens, irritants, and bacteria from entering the deeper layers of your skin. But if the skin barrier is weakened or damaged, it can cause increased trans-epidermal water loss (TEWL), which refers to the process whereby water evaporates through the outer layer of your skin into the air.
When TEWL is high, nasty pathogens can easily enter your skin. This leads to dryness, irritation, itchiness, and even skin conditions such as sensitivity, acne and eczema.
What moisturisers do is that they trap moisture in your skin to prevent it from escaping, and replenish lost moisture in the outer layer of your skin. This leads to a healthy barrier function and helps your skin remain smooth, soft and supple.
Now that you know how moisturisers work, it’s time to talk about the 3 types of moisturising agents commonly found in moisturisers we like to call the ‘H-E-O’ trio. Let’s go!
Humectants - The Moisture Magnets
These water-loving ingredients help to hydrate the skin by drawing in moisture from your surrounding environment and holding it on the skin. Some examples of humectants are glycerin, hyaluronic acid, panthenol, urea, and peptides.
Doesn’t that sound great? Well... there’s just one caveat: it happens only when humidity levels are over 70%.
So, if you live in a humid tropical climate like Singapore or Malaysia, that’s great!
But, if you live in a dry climate (desert, winter season) or if you are mostly in a dry environment (think indoor heaters and air conditioners), they actually draw water from the deeper layers to the surface of the skin, potentially making your skin even drier.
Which is why it’s always good to use a humectant together with an occlusive (more on this later).
Emollients - The Smooth Operators
Emollients are light, oily, film-forming substances that fill in the spaces between dead skin cells in the surface skin and hold them back together into a nice, even layer. While some emollients also function as occlusives (see below) when applied heavily, its main purpose is to help soften, smoothen and condition the skin to improve its flexibility and the appearance of dry patches.
Common emollients include lipids (fats) butters, oils and fatty acids such as shea butter, jojoba oil, stearic acid, and cholesterol, ceramides, etc. They are very important in helping to strengthen and improve skin barrier function.
Occlusives - The Skin Protectors
Occlusives are ingredients that form a water-protective barrier (think saran wrap) over the skin to block and slow down TEWL. They work very well at trapping water, especially when applied on damp skin. This makes it very effective for those with compromised skin barriers.
However, since occlusives are usually oily or waxy substances that sit on top of your skin, the biggest drawback is they can feel quite greasy and uncomfortable.
Some common examples of occlusives are petroleum jelly/petrolatum, mineral oil, candelilla wax, and silicones.
Now you know what goes in the majority of moisturisers out there! Ideally, you want to look for a moisturiser that combines all 3 types, but in varying amounts according to your skin type and climate. This way, it can help to restore your skin’s barrier function, improve hydration levels, reduce TEWL and lead to overall healthier, plumper looking skin!
Does your moisturiser include all 3 moisturising agents? Comment below your favourite type!