The difference between hydration and moisturisation

Ever looked at your moisturiser's (or serum's, or toner's) ingredient list and felt engulfed in a wave of confusion? MECCApedia is here to decode the science, unravel the jargon and give you the knowledge to understand the actives you're slathering on morning and night. Let your skincare education commence!

Even the most casual of skincare fans has heard the hallowed words ‘hydration’ and ‘moisturisation’ a thousand times – after all, they’re the keys to the bouncy, glowy skin that dreams are made of. But what do they actually mean? (Beyond ‘something to do with water’, that is.) And aren’t they just two ways of saying what is essentially the same thing?

Turns out, that’s a no. So join us as we decode the differences – and explain why both hydrating and moisturising products deserve a place in your skincare routine. Because as they say with all good things, por que no los dos?

Keep reading to give your skin – and skincare knowledge – a major boost.

You know how they say ‘oil and water don’t mix?’ Well, they clearly didn’t have their skincare down to a fine art. Because while the two words are (understandably) often used interchangeably, hydration and moisturisation refer to different functions when it comes to skincare.

At its most basic level, hydration is all about replenishing the skin’s water levels, while moisturisation restores its oils. And yes, you need to do both. Just as you need to drink plenty of water and eat a range of healthy fats for your body to function optimally, your skin requires both of these elements to be in balance as well.

Often, hydrating the skin occurs at a deeper level (looking at you, hyaluronic acid), really penetrating the skin, while moisturisation restores the skin’s protective lipid barrier (think those nice rich occlusives that seal all the hydration in, like a night cream). We’ll take one of each, thanks.

Hydration is important because water – and the vital, naturally-occurring substance that binds water molecules in the skin, hyaluronic acid – is what keeps our skin plump, smooth, and radiant from within. When our skin lacks hydration, we will often see it reflected in the mirror via flakiness and premature fine lines, or simply looking a bit tired.

Dehydrated skin also lacks that luminous, juicy glow we all crave – and it can make makeup application patchy while reducing its staying power.

Meanwhile, moisturisation is all about replenishing the outer layer of the skin to protect and restore its moisture barrier, which is made up of lipids (the skin’s natural fats).

This barrier can be weakened if the skin is producing very little oil, which can be a result of genetics or hormonal fluctuations, and indicate a dry skin type. The moisture barrier can also become temporarily compromised when we use harsh products that strip away the skin’s natural lipids.

Noticing redness, sensitivity, flakiness, or a parched, ‘tight’ feeling? Dryness could be the culprit. The solution? Moisturising products that restore balance, nourishment, and comfort to the surface of the skin.

The short answer is yes. Often, people with dry skin will experience dehydration as well as dryness. This is because the skin’s lipid barrier is responsible for locking in hydration. If this barrier is damaged or weakened, water can escape more easily, so even if you’re applying your hyaluronic acid and other hydrators, they aren’t being retained by the skin. This can lead to a double dose of dryness and dehydration.

On the other hand, people with oily skin can also be dehydrated (yep - really!) especially if they are using anti-acne products designed to break down excess oil, which can compromise the skin’s moisture barrier. This can leave you stuck in a vicious cycle of trying to dry out the excess oil, which in turn signals your skin to produce more to compensate.

A daily hydrating serum is the perfect place to start as these products tend to contain a high concentration of active ingredients, delivering water-binding molecules to both the surface and deeper layers of the epidermis.

Look for humectants like hyaluronic acid, sodium hyaluronate, PCA and glycerin, which pull hydration into the epidermis like a magnet. And remember, serums should always be layered with an occlusive like a moisturiser or oil, to lock water into the skin – even if your skin is on the oilier side.

Hydrating serums should also be used in conjunction with exfoliation and sun protection.

Using pH-balanced exfoliating acids – like glycolic and lactic acid – can help to dissolve the flakiness often associated with dehydration, and enhance the overall radiance of the complexion. Meanwhile, using SPF daily can help to prevent the dehydration caused by excessive sun exposure.

A daily hydrating serum is the perfect place to start as these products tend to contain a high concentration of active ingredients, delivering water-binding molecules to both the surface and deeper layers of the epidermis.

Look for humectants like hyaluronic acid, sodium hyaluronate, PCA and glycerin, which pull hydration into the epidermis like a magnet. And remember, serums should always be layered with an occlusive like a moisturiser or oil, to lock water into the skin – even if your skin is on the oilier side.

Hydrating serums should also be used in conjunction with exfoliation and sun protection.

Using pH-balanced exfoliating acids – like glycolic and lactic acid – can help to dissolve the flakiness often associated with dehydration, and enhance the overall radiance of the complexion. Meanwhile, using SPF daily can help to prevent the dehydration caused by excessive sun exposure.

As moisturisation is all about repairing and maintaining the skin’s lipid barrier, look for moisturisers featuring shea butter, ceramides and squalane, and oils rich in fatty acids like omegas 3, 6 and 9.

These ingredients replenish the skin’s protective matrix, preventing water from escaping throughout the day and night, and maintaining a smooth and resilient complexion. A healthy lipid barrier also prevents bacteria and chemicals from penetrating the surface of the skin, helping to keep skin looking and feeling soothed and calm.

For those with acne-prone or oily skin, lightweight, non-comedogenic moisturisers (read: moisturisers that won’t clog pores) are a must to prevent breakouts and excess shine.

Meanwhile, dry skin types should be mindful to pair their moisturisers with gentle, nourishing cleansers that work in synergy with moisturiser to maintain a soft, balanced and luminous complexion.