We see our skin all the time. Yet, for most of us, it remains a mystery. It cloaks and protects us not only from the outside world but it also cloaks us in feelings, opinions and questions.
Skin acts as a barrier to the outside world and because it contains millions of nerves allows us to literally feel our way through life.
Skin is vital for our day to day survival and functioning. It also reveals so much about who we are and how we see ourselves and others.
Skin is the most fascinating or all our organs and yet, most of us take it for granted.
Until something goes wrong.
Our skin is scratched, stretched and squashed hundreds of times a day and yet it doesn’t break or wear out. It is subjected to intense UV radiation but stops it from touching our internal organs. It holds off bacteria and fungal invaders and is in a constant battle to maintain our bodies temperature.
The least we could do is offer this hard-working organ a little help.
One of the easiest and most helpful things we can do for our skin is to keep it moist.
The best way to do that is by applying moisturizer.
What is Moisturizer?
Moisturizer is a product that contains ingredients that keep the skin’s barrier – the epidermis – soft, supple, flexible and strong. There are three components that make up moisturizer:
Humectants, emollients and occlusives. I’ll get to those in a moment.
First, you need to know why your skin needs to be kept moist to remain strong.
The Layers of Your Skin
Your skin is made up of layers. The top layer is called the epidermis.
The epidermis is about as thick as a piece of paper and one of its jobs is to shield us from damage caused by our environment.
It does this through living brickwork made up of keratinocyte cells. These cells are made from a protein called keratin. This is the same protein that your nails and hair are made from.
Keratin is unbelievably strong. It is also found in the animal kingdom in the form of unbreakable animal horns and claws capable of shredding through tough animal hides.
What Makes Skin Dry?
Water is the most important molecule in the human body and our skin. The very top layer of our skin, the stratum corneum has a primary function.
That is to act as both a barrier and a shield.
As a barrier, it prevents water loss.
As a shield, it stops microbial and bacterial invasions, it shields us from ultraviolet radiation (UV) damage from the sun and gives as a small amount of protection from mechanical damage.
Your Skin Is A Barrier That Prevents Water Loss
Keeping the water levels within your skin in optimal health depends on a few factors.
- Your skins natural moisturizing ability also called natural moisturizing factors (NMF)
- The overall health of the outer barrier
- The oil-based molecules between the corneocytes also called the lipid matrix
The lipid matrix contains a mixture of oil-based molecules.
These include ceramides, cholesterol and free fatty acids (such as lactic acid).
All three of these molecules are required to create a healthy and strong skin barrier.
They are tightly interlinked within the matrix.
These molecules being oil-based repel water from the outside and keep water on the inside. They are able to do this because these lipids are made with ‘water-loving’ heads (called hydrophilic) and water-repelling tails (called hydrophobic).
A double layer of these molecules is formed with the heads on the outside and the tails in the centre.
This forms a hydrophobic (literally ‘scared of water’) centre.
Because the centre of this layer repels water it is held in the water-loving heads. The tails prevent the movement of water across the membrane to prevent TEWL.
We’ll get to TEWL in a moment.
Each corneocyte cell is a dead keratinocyte cell. I the stratum corneum it is surrounded by a protective oily lipid matrix layer.
This fusion of the corneocytes in a liquid bed makes the skin not only waterproof but also flexible and able to be moved and stretched without tearing.
Skin is such a perfectly designed organ!
A number of factors can affect the function of the skin barrier, including genetics, environment, lifestyles habits and even diet.
Some skin conditions with a genetic component such as eczema are caused by an impaired skin barrier.
Also using the wrong skincare products and ingredients for your skin can damage your skin’s barrier.
When the barrier is damaged not only can water can escape through the channel, but there is now a pathway into the skin for allergens and irritants.
A damaged skin barrier becomes dry, flakey, irritated, itchy and inflamed. Not the ideal skin condition.
Dry skin is a sign of a damaged or unhealthy skin barrier. Your skin can be lipid or oil dry, water dry or dehydrated skin or both.
Dehydrated skin occurs when your environment is dry. Also from air conditioning, internal heating and especially when flying.
Fun Fact: Aeroplanes are kept extremely dry – about three times dryer than the Sahara Desert!
Lipid dry skin, you know the dry flaky skin you see after a long haul flight occurs because of TEWL.
What is TEWL?
TEWL is the technical term for water loss from your skin. It stands for TransEpidermal Water Loss. Transepidermal water loss is when water evaporates through the epidermis.
When TEWL is high your skin because dry, itchy, flaky and sometimes irritated.
The stratum corneum has a ‘brick wall’ structure and this is to prevent TEWL as well as prevent bacteria and irritants from entering. When your skin lacks enough lipids to create this protective barrier, TEWL occurs.
When there is more water in our skin than in the outside air, our skin will try and restore the balance by pulling water from the deeper layers of our skin.
When the water levels of our skin are not in balance the protective barrier can’t work properly. This effects the skins natural ability to shed the top layer of dead skin cells.
This means that the dead skin cells stick around longer and are not replaced by fresh news ones which make our skin lose even more water.
Fortunately, dehydrated skin is easily fixed by drinking lots of water and good skincare.
What Type Of Dry Skin Do I Have?
First, it is important to work out what kind of ‘dry’ your skin is.
Is your skin dehydrated from lack of water and a dry climate, or have you been working in a heated air-conditioned office all day?
Do you have dry skin as a long term condition? People who have chronic dry skin suffer from naturally low oil and ceramide levels.
No surprises that chronic dryness is accompanied by sensitivity. This is because the skin’s barrier is very weak.
Folks with dry skin are more susceptible to inflammation, redness and dermatitis. You will react more to sensitising ingredients, climate change, and a change in your diet than those with oily, combination or normal skin.
If your skin starts to appear dull, rough and flaky it’s a sign of lipid dryness.
Lipid dry skin can have a matte appearance and lacks radiance and sheen.
It is dry and rough to the touch and doesn’t have a natural ‘slip’.
Oil dryness tends to be a chronic condition and those who have it often experience premature ageing and skin sensitivity because the skin barrier is compromised.
The delicate barrier of lipid dry skin constantly needs to be supplemented with nurturing oils that should behave like the skins own sebum.
A good moisturizer should contain ingredients to lubricate the skin and stop it from losing too much of its own water through TEWL.
What makes skin dry?
In most cases, dry skin is related to one or more of the following factors: Natural moisturizing factors, genetics, environment and your skincare routine and ingredients.
Your skin has the ability to makes its own natural moisturizers. Its the very imaginatively named natural moisturizing factors.
What are Natural Moisturizing Factors
Your skin has an amazing ability to regulate how much it moisturizers itself, based on the environment in which you live.
It does this by using what is called natural moisturizing factor (NMF) to pull moisture content from the air into your skin cells.
There is a variety of factors that contribute to how much NMF your skin produces, and this can affect the skins ability to retain moisture.
How Does Natural Moisturizing Factor Hydrate Your Skin?
Natural moisturizing factors are made up of amino acids and humectant that are by-products of a structural protein called filaggrin.
Your skin can take those by-products and recycle them to make NMF. It then uses the NMF – which is located within cells in the stratum corneum – to regulate its moisture content. The role of NMF is to draw in water from the air to the skin, keeping it hydrated.
Hyaluronic acid is an NMF that is made by your skin. You make less and less NMF as you age.
The good news is that you can add them back into your skin topically, with formulations that contain synthetic NMF.
Natural moisturizing factor also plays a defensive role, helping to create a barrier so that harmful microorganism can’t penetrate your skin.
How Much Natural Moisturizing Factor Does Your Skin Make?
Your body can regulate how much NMF it makes.
If you live in a low-humidity environment, your skin will naturally produce more NMF than if you lived in a high humidity environment. Your skin takes about three days to adjust to a new environment.
This is why your moisturizer may need to change from season to season and if you move or travel long distances from one seasonal zone to another.
People with dermatitis and eczema make less NMF. There is believed to be a genetic component to how much NMF your skin will make.
People with dermatitis have a gene mutation that reduces the amount of filaggrin they are able to make in their skin.
Exposure to UV light and harsh surfactant ingredients can also decrease NMF production.
There is no way to stimulate your skin to make more NMF, so caring for your dry skin involves maintaining a healthy skin barrier.
Now we understand a bit more about our skin and why it needs moisturizing let’s look at what moisturizer actually is.
Moisturizers are divided into three categories:
Attract water. These small molecules attract and hold water, in some cases up to 1000x there own weight in water. They occur naturally in our skin and are found in the epidermis and the dermis.
Humectant stops your skin from becoming dehydrated from water loss. Hyaluronic acid is one of my favourite ingredients in skincare products and this is because it is a water-loving beast.
A word of caution with humectants. While they can hydrate your skin from drawing water from the air, they can also dehydrate your skin by drawing moister from the deeper layers of your skin when the air is dry.
These molecules keep the surface of your skin hydrated because they are usually to big to penetrate below the epidermis. It’s still important to keep the surface of your skin hydrated as this stops the very fine lines that can happen when surface dryness occurs.
Common Humectants in Skincare Products – The Good Guys
- Hyaluronic Acid
- Lactic Acid
- Sodium Lactate
- Sodium PCA
Humectants are great but they need oil or wax to lock in the moisture that they attract. The ingredient that locks moisture into place is called emollients.
Are oils that soothe and soften the skin. They do this by filling in the microscopic rough grooves and ridges on the skin. Emollients are lightweight molecules that leave the skin feeling moisturized and lubricated without the thick heavy feeling of occlusives.
Emollients can have other skin benefitting properties. Some oils act as anti-inflammatories and are useful for calming sensitive or red skin. Some contain essential fatty acids such as squalane which helps reinforce the skin’s barrier.
Many emollients used in high-quality skincare have a similar molecular structure to the sebum found naturally in our skin.
Emollients That Mimic Sebum – The Good guys
- Jojoba oil (This is technically a wax, but I include it here because it’s great)
- Sea Buckthorn Oil
- Marula Oil (The cornerstone product of the Drunk Elephant range)
- Meadowfoam Oil
- Grapeseed Oil
- Blackcurrent seed Oil
- Shea Butter
- Castor Oil
- Argan Oil
Not all emollients are good for your skin. Some are comedogenic – which means they clog or block your pores. They may not this straight away. It can take months of using comedogenic products before your skin shows signs of blocked pores
Common Emollients To Avoid
- Coconut Oil
- Almond and Peach seed Oil
- Oleic Acid
- Cocoa Butter
- Coconut Oil
- Flax (Linseed) Oil
- Isocetyl Stearate
- Lauric Acid
- Linoleic Acid
- Mineral Oils
- Safflower Oil
- Sunflower Oil
- Wheatgerm Oil
Avoid comedogenic oils even if you don’t have oily skin.
Like emollients, occlusives help to reduce water loss. Unlike emollient, they do this by forming a thick seal over the skin to physically stop water from escaping.
Occulsives are best applied to damp skin so that there is water on the surface to lock-in. The best types of occlusives are hydrogenated – which just means thickened castor bean oil and non-comedogenic waxes.
Use occlusives with caution as many of them contain comedogenic ingredients and are very heavy and greasy. Only use occlusives if you have very dry or flaky skin. They are often used after clinical treatments, such as cosmetic grade peels.
These are not recommended for most skin types and defiantly not for oily or acne-prone skin. Occulsives can trap the oil and bacteria and cause blocked pores and hair follicles.
- Petroleum Jelly: This is a very heavy duty occlusive and I would only recommend using this on diaper rash for babies. It has no other skin benefits.
- Thickened Castor Bean Oil: This is great! Castor Oil contains built-in anti-inflammatories from ricinoleic acid so it is very good for sensitive and irritated skin
- Lanolin: Pharmaceutical or cosmetic grade lanolin is best because all the pesticides and impurities have been removed. Lanolin allergies while rare, but more common in those with eczema and skin sensitivities. It’s often the chemicals that have been sprayed on will that cause skin irritation and allergy from this ingredient.
- Seed and Nut Butters: Shea butter is one of the best occlusives butter because it has added anti-inflammatory benefits.
How Can I Help My Skin Stay Moisturized?
Regardless of the type of dry skin you have, there are a few things you can do to improve the functioning of dry skin.
Stay hydrated. Drinking plenty of water is great for your skin and for your body in general. So try to aim for at least 6 glasses of water plus other fluids per day.
Keep your skin barrier protected with a hydrator and an occlusive. Hyaluronic acid is one of the best hydration to use but if used on its own in a dry environment it can make skin dryness worse by drawing moisture from your skin instead of from the air.
For this reason its a good idea to use humectants with occlusive if you have dry skin and especially f you have dermatitis or eczema.
Repair and soothe your skin with non-acne causing oils and skin acids.
Bottom Line On What is Moisturizer
Dry skin is caused by two factors. Lack of water or lack of oil.
When either of these things happens the skin’s barrier loses it’s the ability to hold onto water. Moisturizer is either a combination of humectants, emollients and occlusives.
Even oily skin can benefit from moisturising. Moisturising restore the skin natural barrier and using overly stripping cleansers, toners or excessive exfoliation can disrupt the barrier for oily skin just as much as for dry skin.
You should cleanse your skin with an appropriate cleanser, treat it with serums and then reinstate your skins natural barrier with moisturiser.
And sunscreen, always wear sunscreen.