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Trans Epidermal Water Loss (TEWL) and why we LOVE fish oil at Dermal         

When we hear the word dehydration we immediately think of water. And yes….water is our body’s most essential nutrient: we can only last 3-4 days without it.  But when it comes to our skin, only 12% of the water we drink will actually reach our skin.  So that makes it super important to preserve the little we have.  How can we do that?  With oil!!!

Think about a glass of water.  If you pour oil on the top on that glass of water it sits on the top.  It provides a protective film over the water, preventing evaporation.  Without that film, we could leave the glass in open air and slowly it would just evaporate away over time.   So that makes the oil even more important than the water!!!

Sadly, our western diet and love of exfoliating treatments can affect our oil/water barrier.

The cell- Where it all begins

The cell has 3 main components.  The nucleus, cytoplasm, and the cell membrane.

The cytoplasm is the cellular fluid inside a cell.  This is where the fluid we drink is so important. It gives the shape to the cell.  It makes it a plump grape, rather than a shrivelled sultana.

The cell membrane (lipids) is what keeps the plump grape from evaporating (too early) into the sultana. It has what is called a Phospholipid bi Layer. These are Hydrophillic heads that love water and hydrophobic tails that don’t like water. The tails are made Essential Fatty Acids, hence why we need EFAs.  It holds the fluid in place as it travels up through all the layers of the skin, releasing its contents on to the skins surface at just the right time – I’ll get to that part soon.

Building the cell

We can’t build a house without all the right materials, just the same as our body can’t build a cell without the right materials. Our cells are first created in our lowest layer of the skin, the basal layer. They are made by stem cells which are the builders of our ‘house’.  These cells make all the new cells. 95% are keratinocytes and the remaining cells are langerhams, (immunity) and melanocyte (skin colour) and merkel cells (touch sensation).  But the hero in this story is the keratinocyte.

When a stem cell builds a cell it needs:

  • The right building blocks: nutrients which come from our food, which is processed in small intestine and then distributed in our blood to cells through circulatory system.
  • Energy: Our capillary dermis feeds oxygen into the blood, which then feeds  to cells, which then gets converted to energy (ATP).


The life of a cell

In the perfect cellular world – the new cell travels up to the next  layer of the skin the stratum spinosum.  Here the cell is nice and juicy and plump with a healthy cell membrane.  When they reach the next layer (granulosum) the membrane begins to decompose and leak out the cytoplasm.  So at this point,   we have a mix of oil and water (just like the oil in glass example previously ) and the two materials begin to arrange themselves.  Oil (lipids) on top, keeping the water in. This is the creation of our acid mantle.

What’s the acid mantle

Our acid mantle is our skins barrier.  If it is healthy, it will have an ideal acidic PH of about 4.5-6.5, it will keep  pathogens out, it will slow absorption of actives. and it will halt TEWL by preventing the water evaporating.

However, if it is not healthy it will not be capable of doing any of these things.

1             It might be because when the stem cell built the cell, it didn’t have the right materials.  It didn’t get enough nutrients to make the all important barrier, so the decomposing of the barrier began too early.  So instead of a slow release on the outer layers of the skin, if broke apart in the lower areas, leaving the top layer exposed and parched.

2             Pathogens can now enter our skin as the barrier is impaired and there are gaps in our barrier.

3             This now means the products we use absorb faster.  That sounds good right? NOOOOOOO!! Serums and moisturisers are designed to slow release at a deeper level.  If it’s going in too fast then it creates irritation and sensitivity, because the langerham cells, I mentioned before, think they are under attack, so they create an inflammatory response. Not only that, when the hydrating serum is applied, the top layer is greedy.  It’s been thirsty for so long.  So it drinks up everything, leaving nothing for the layers underneath.

4             Our skin layers thicken and become dull and uneven.  We should be turning over skin cells every 28 days.  When we make new ones, old ones need to go. There is a helpful little enzyme that exists in the outer most layer, that has a job of breaking down the bonds that hold cells together.  However this enzyme is very fussy about its work environment.  It only works in water, so in a dehydrated state in switches off.  So our shedding process stops working properly and our skin starts to see problems like uneven skin tone, pigmentation, thickening, acne and dullness.

4             Finally, the stratum corneum talks to all the other layers of the skin.  But without water, the controls of this communication, things start to go haywire.  So the SC feels dry now so it tells the sebaceous glands to send more oil.  But there are too many old cells still hanging around and blocking the follicles so acne may ensue.   Or the skin is feeling irritated so the langerham cells create inflammation to protect our skin from the invaders.  Our melanin cells start producing more pigment as they are also doing their bit to protect the skin.

So we can see, Dehydration is the first domino in the line of all skin conditions and must be treated before secondary issues such as pigmentation, acne and premature ageing.

What can we do to repair our acid mantle?

The nutrient we most need to build a healthy cell membrane and thus a healthy skin barrier are Essential Fatty Acids (EFAs). Our body distributes these though via a hierarchy system. Organ number 1 is brain, (the brain is 70% lipids, so it needs lots).  As an interesting side note:  1 in 5 suffer mental health and EFAs are increasingly being found to improve this state.

What is left over after the brain takes what it needs, will go the next most important organ, and so on and so on,   until the last organ, our skin, gets some EFAs.  So you can see, there is not much chance of that stem cell getting the building materials it needs.  Supplementing our diet with Essential Fatty Acids is a necessary measure if we want to give our skin its best support (and of course our brain and all our other organs).

Not all Essential Fatty Acids are the same

Essential Fatty Acids are just that – essential.  There are 2 types.  Omega 3 (alpha linoleic acid) and 6 (linoleic acid) – you may have heard of 9 but this can be produced by the body and therefore non essential.  Both are necessary but the correct balance is important.  We should eat a ratio of 4-1 (6 to 3), but western diet has the ratio up to 50:1.  Omega 6 primarily gives us energy but will also be stored as fat. Omega 6, which comes from grains,  also has high levels of prostaglandins 2 which is inflammatory.  Omega 3 has Prostaglandins 1 and 3 which are pro inflammatory.  We need both but we have too much Prostaglandins 2 already in our diet and not enough 1 and 3 to control it.

So what we are really looking for when we chose an EFA is Omega 3.

Just to make this even more complicated, within Omega 3 there are a number of types. The main 3 are ALA, EPA and DHA.  ALA and DHA give us energy and a few other important things, but the star is EPA.  EPA is responsible for increasing our good cholesterol, reducing inflammation, improving mental health, brain development and protecting against dementia, reducing weight and fatty liver, supporting bone health and asthma. So we want to find a supplement that is higher is EPA but will still include DHA.

Some of the well known EFAs are Fish oil, Flaxseed oil, Safflower, evening primrose.

Flaxseed– is very popular because it’s one of the highest forms of EFA.  But referring back to what we’ve just said  (above) it contains: 18% omega 6 and 57% omega 3 but the ALA type.  So it has a less effective omega 3 and more omega 6 which we don’t need.

Safflower has 76% omega 6- more inflammation.

Evening primrose is found to be very helpful for hormone health but it is an Omega 6.

Fish oil not oils are the same.  A good quality oil will have 750mg of EPA and 500 DHA per teaspoon but if you look at the nutrition panel on some cheap brands you need around 10 capsules per day to get your daily dose. What determines the quality is where a fish was farmed, what it has been fed, and the size of the fish.  A small fish like krill will feed on algae and seaweed where as a farmed one will be fed on imflammatory grains and antibiotics.  The big fish will eat the small ones so the potency of EFA will be less in a larger fish.

Vegan/Vegatarian – If you are vegan you will find it hard to get the level of EPA and DHA required but Free Spirit is a good algae form.

Dosage may be anywhere between 1000-10000mg per day depending on skins condition.  EFA should be taken with food and ideally with fat.  You will see improvements after one month as the cells are created every 28 days or so.

If all this just sounds confusing, you can rest assure we have already done the research at Dermal and we now retail Nordic Naturals which at this stage is the highest EPA and DHA content we have found on the market.

Source:  APJ journal, Lia Trebilcock: skin education international ,


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