What is a moisturiser?
It interests me as an aesthetician that few textbooks in dermatology devote little space to this subject.
No standard definition really exists, yet we use and recommend moisturisers daily?
Technically a moisturising treatment involves this 4-step process:
- repairing the skin barrier
- increasing water content
- reducing trans-epidermal moisture loss (TEWL)
- restoring the lipid barriers ability to attract, hold and redistribute water
In my opinion, they are a vital part of the skincare routine when it comes to skin health.
So join me as I decode your moisturiser, so you can appreciate how much of a role it plays in your skin’s health.
The importance of moisturtising
- they replenish natural oils on the surface of your skin
- a well-formulated SPF moisturiser can prevent signs of photo-ageing
- they provide a soothing, occlusive film, helping to calm inflammation
- an emollient moisturiser will help to keep your skin soft, supple and youthful
- they can contain cosmeceuticals that help to improve the appearance of ageing skin.
- an antioxidant-rich moisturiser prevents free radicals from causing ageing oxidation
- a humectant rich moisturiser will help to lock in moisture and maintain hydration, slowing evaporation
- balancing ingredients can be incorporated, that will slow down the flow of sebum to the surface of your skin
- a gentle, intelligently formulated moisturiser will replenish the delicate microflora that makes up the acid mantle
- moisturisers can contain lightening and brightening ingredients, helping to pull deep-rooted pigmentation from within your skin’s tissues
- they cover tiny fissures in your skin, filling the cement-like substance between the cell walls to maintain the all-important protective barrier function
How do moisturisers work?
Traditionally, they were believed to inhibit transepidermal water loss. Water begins in the deep epidermal layers and moves up to hydrate cells in the stratum corneum your outer layer of skin, eventually being lost to evaporation; the occlusive moisturisation helps prevent dehydration of the stratum corneum.
Fortunately, today much more is now known about the function and skin layers.
The “bricks and mortar” model I discuss here, suggests that its role is as an active membrane. Loss of intercellular lipids, such as important ceramides, cholesterol, and fatty acids, which form the bilayers of your skin can damage the barrier function, causing a whole host of skin conditions.
Your skin has a natural moisturising factor (NMF), a mixture of amino acids, lactates, urea, and electrolytes, which helps the stratum corneum retain water. Typically a dry skin occurs when the moisture content is less than 10%.
The components that create a moisturiser
Several groups of substances are based on their activity on the skin:
Occlusives form a film over the surface of your skin, creating a protective barrier and preventing TEWL. Follow the link to find out more about these important ingredients.
Humectant rich ingredients
Humectants attract water when applied to your skin, improving hydration of the stratum corneum.
Your skin’s natural moisturising factor comprises a mix of low, molecular weight, hygroscopic substances including; glycerin, sorbitol, urea, amino acids, sodium PCA, and alpha-hydroxy acids such as lactic acid. This natural compound is known to be a major player in keeping skin hydrated and flexible.
The naked chemist products contain all of the following skin-identical ingredients – urea, amino acids, glycerin, sorbitol, hyaluronic acid, lactic acid, ceramides, cholesterol, and fatty acids.
All of these work to increase the cohesion of the stratum corneum cells, protecting your barrier function, maintaining the NMF, and keeping your skin soft, supple, plump, and youthful.
You have to be careful of with humectants, is that water drawn to your skin is trans-epidermal water, not atmospheric water. Continued evaporation from your skin can actually exacerbate dryness; this is the reason why we suggest layering your humectant based products such as our H20 hydrating complex or Quench ultra-hydrating gel with an occlusive ingredient.
These ingredients give a product that immediate feel of moisturisation.
Emollients improve skin texture by smoothing the skin and offering great slip. They play an important role in binding desquamating corneocytes in the epidermis, filling in the spaces between the skin flakes – like mortar between bricks with droplets of oil.
When combined with an emulsifier, they hold both oil and water in the stratum corneum. Vitamin E is a common additive, as is cholesterol, squalene, jojoba, and structural lipids.
Stearic, linoleic, linolenic, oleic, and lauric – found in palm oil, coconut oil, and wool fat. are long-chain saturated fatty acids and fatty alcohols. These change the properties of intracellular lipids in the stratum corneum. They are used in topical cosmetic formulations, where they exert their benefits through effects on the skin barrier and permeability.
Essential fatty acids such as linoleic acid and alpha-linoleic, work by influencing skin physiology via their beneficial effects on the skin barrier functions, membrane fluidity, and cell signalling.
Structural lipids are intracellular lipids located between the stratum corneum cells; they play a major role in the skin’s water-holding capacity. Ceramides are a major component of the inner cellular lipids and are vital in maintaining skin health and improving dry skin conditions.
Do moisturisers that contain collagen work?
Collagen and other proteins, such as keratin and elastin, claim to rejuvenate the skin by replenishing essential proteins within your skin. This is unlikely to happen since protein molecules are too large to penetrate through the skins outer layer.
When these ingredients are applied topically, they shrink slightly, providing a temporary protein film that appears to smooth the skin and stretch fine lines.
Alpha hydroxy acids in moisturisers
Alpha hydroxy acids like glycolic and lactic, absorb deep within your skin tissues. Because of their small molecular structure, they can dissolve surface cells that adhere to the skin’s surface, making your skin smooth and more hydrated.
As you can see, different classes of moisturisers are based on their action, whether that be occlusive, hydrating as an emollient, or rejuvenation.
When considering skin health, having a fundamental understanding of the physiochemical effects of moisturisers and how they interact with your skin and the barrier function, this will give you an added advantage in preventing and treating your skin type and any skin disorders you may have.
The importance moisturising: https://www.utmedicalcenter.org/the-importance-of-moisturizing
Why moisturising your face is important: https://www.reviewthis.com/why-moisturizing-face-is-important/
5 reasons to moisturise your skin: https://www.burkewilliams.com/blog/2014/10/23/5-reasons-must-moisturize-skin-2
The role of moisturisers: s://aestheticsjournal.com/feature/the-role-of-moisturisers-in-skincare