Skin biology: layers, collagen and the skin barrier

Deep dive · Skin at Health Royals · 7 min read

Skin is not a surface to be corrected. It is a layered, self renewing organ, and most of what changes in it over the years happens in one of three jobs it does at once: structure, water and barrier.

Nutrition for skin at Health Royals

Beauty Complete is built around the three jobs the skin does at once: 500 mg Cartidyss® fish cartilage collagen chosen around structure, 120 mg Hyabest® hyaluronic acid chosen around water and 30 mg Ceramosides™ phytoceramides chosen around the barrier, each at the dose used in its own human study, with 60 mg vitamin C as PureWay-C, 1.4 mg vitamin B2 and 50 µg biotin. Vitamin C contributes to normal collagen formation for the normal function of the skin. Biotin contributes to the maintenance of normal skin.

See Beauty Complete, marine collagen and hyaluronic acid

How is skin structured?

The skin is the body's largest organ. It shields against the environment, regulates temperature and fluid balance, takes part in immune defence and communicates with the nervous and hormonal systems. It does all of that through three connected layers.

The epidermis is the only layer a cream reaches in any meaningful way. Everything associated with firmness and bounce sits one layer below, in the dermis, which turns over its collagen across months and years and is supplied from inside, through the bloodstream.

Skin is three layers with three different jobs, and only the outermost one is within reach of a cream.

Why does skin get dry?

Because three things change at once, and they are not the same thing. Structure: collagen turnover slows, so the dermal scaffolding is renewed more slowly. Water: the glycosaminoglycans in the dermis, hyaluronic acid among them, decline, and with them the water rich environment around the cells. Barrier: the lipid layer that limits water loss becomes less efficient, so the moisture that is there leaves faster. A cream works on the third from outside; the other two are supplied from inside. Why this happens, how the menopause years change the picture and what helps is covered in Dry skin: why it changes with age.

Dry skin is rarely only a surface problem. It is usually structure, water and barrier changing together.

What do collagen and elastin do in the skin?

Collagen accounts for much of the skin's dry weight. Together with elastin it forms the dermal matrix, the mesh produced by fibroblasts that keeps skin firm and flexible. Collagen contributes tensile strength, elastin the recoil, and the two are not interchangeable.

Between those fibres sit the glycosaminoglycans. Hyaluronic acid is the best known, a molecule that binds large amounts of water, fills the spaces between collagen fibres and cushions the tissue. Structure and water are physically interleaved in the dermis.

Collagen taken by mouth is a protein and is digested like any other, into peptides and amino acids. It does not travel intact to the skin. Research has asked a narrower question: whether a defined daily amount of a defined collagen preparation is associated with measurable changes in the skin over time, against placebo.

That is also why the word collagen on a label says little on its own: fish skin, fish cartilage and bovine hide give different materials, studied at doses from tens of milligrams to grams. When Health Royals chose the collagen for Beauty Complete, we started from a named raw material with a human study on that very material, not from the category. More on the types and sources.

Collagen is the tensile scaffolding, elastin is the recoil, and hyaluronic acid is the water held between them.

What is the skin barrier and why does it matter?

The barrier is the outermost part of the epidermis, the stratum corneum: flattened cells held in a lipid matrix of ceramides, cholesterol and fatty acids, often described as bricks and mortar. It keeps water in and irritants out with the same structure.

When the mortar thins, water leaves faster, the skin feels tight and reacts to things it used to tolerate. Low grade inflammation works on the same repair capacity: it weakens the barrier, disturbs collagen balance and contributes to dryness, redness and sensitivity, a cycle influenced by nutrition, stress, hormones, sleep and the skin microbiome.

Ceramides make up most of the mortar and can decline with age, which is why the third raw material in Beauty Complete is Ceramosides™, a phytoceramide from Seppic in France, at 30 mg a day, its studied dose. More in our guide to ceramides and the skin barrier.

A barrier that is losing water and a barrier that is easily irritated are the same problem seen from two sides.

What happens to skin as you age?

Cell turnover slows and the production of collagen and glycosaminoglycans declines. Skin may appear thinner, drier or less elastic, not because it is failing but because it is adapting to new conditions.

Oxidative stress is the quiet accelerator. Sunlight, pollution and ordinary metabolism generate reactive oxygen species, unstable molecules that can damage lipids, proteins and DNA, speed collagen loss and trigger inflammation. The body's antioxidant systems, including enzymes such as superoxide dismutase, neutralise much of it, and tend to weaken with age.

Hormonal transitions add their own timing. Around menopause and midlife, several of these changes arrive closer together, which is why the shift can feel abrupt even though the processes are gradual.

Ageing skin is not failing skin. It is a slower renewal cycle meeting the same daily load.

How do sleep, sun and stress affect the skin?

Sunlight is the largest external contributor to collagen breakdown over a lifetime, through the reactive oxygen species it generates in the dermis. Daily protection does more for skin structure than almost anything applied afterwards.

Sleep is when the body does most of its repair, and short sleep shows up as dullness and slower recovery. Long term stress feeds the same low grade inflammation that undermines the barrier, and tends to arrive with the habits that make skin worse: less sleep, hurried meals, less water. More on how stress and sleep work.

Sun protection, sleep and stress load act on the same three systems that a routine is trying to support.

What should you eat for healthy skin?

Skin is built from what the rest of the body has available, so a varied diet, enough fluid and regular meals do more than any single nutrient. A few nutrients have documented roles worth stating precisely.

Vitamin C contributes to normal collagen formation for the normal function of skin. Biotin and vitamin B2 contribute to the maintenance of normal skin. Zinc contributes to the maintenance of normal skin. Those are authorised wordings and we use them as written, and Beauty Complete carries vitamin C, vitamin B2 and biotin.

Research has also examined omega 3 fatty acids, studied in relation to photoprotection and skin, and hydroxytyrosol, an olive polyphenol studied for its antioxidant behaviour. Both are in Peak Performance Formula, our daily multivitamin for women.

Diet works on skin the slow way, through the material and the conditions available for renewal.

Where do collagen supplements fit?

On top of the foundation of diet, sleep and sun protection. A collagen supplement is judged by its raw material and studied dose, not by the word collagen.

Fish cartilage is not fish skin. Skin gives type I collagen and little else; cartilage gives type II collagen with chondroitin sulphate and other glycosaminoglycans, the same family of water binding molecules found between the collagen fibres in the dermis, which is why we looked at cartilage. The raw material in Beauty Complete is Cartidyss®, a fish cartilage hydrolysate made by Abyss Ingredients in Brittany, a specialist manufacturer of marine raw materials with traceable sourcing, the kind of manufacturer Health Royals looks for.

In a double blind, placebo controlled study on Cartidyss®, published in Molecules in 2021, 46 women aged 45 to 59 took 500 mg a day or placebo for 90 days. The study reported reduced wrinkle measurements and increased dermal thickness in the group taking the material. Cartidyss® was studied at 500 mg a day. Beauty Complete contains 500 mg per daily dose. Ninety days also means taking it every day for three months, which is why the jar is designed to stand out on a shelf and become part of the routine.

The same reasoning runs through all six ingredients. Hyabest® hyaluronic acid, 120 mg, is bio fermented by Kewpie in Japan to a defined molecular weight, at the daily dose used in its human studies; Ceramosides™ phytoceramides, 30 mg, from Seppic, likewise. Vitamin C as PureWay-C, 60 mg, vitamin B2, 1.4 mg, and biotin, 50 µg, sit at a nutritional level. For us, the ingredient cannot be separated from its source, manufacturer and studied dose.

A higher number is not automatically a better or more evidence based dose. What matters is the specific raw material and the dose that was actually studied; why milligrams and grams are not on the same scale is covered in How much collagen per day.

Understand the biology first, then judge a supplement by its named raw material, its dose and what was actually measured.

We have done the selection so that you do not have to. Beauty Complete is our supplement for skin, and our skin page collects the wider context.

Read the collagen need guide

Go deeper

• Guide: skin from within
• Dry skin: why it changes with age
• Cartidyss®: the fish cartilage collagen in Beauty Complete
• Oral hyaluronic acid and skin hydration
• Ceramides and the skin barrier
• The biology of healthy ageing
• The biology of menopause
• Why we use capsules and not powders

Frequently asked questions

Why does my skin feel tight after washing?
Tightness is usually a barrier signal. Cleansing that removes too much of the lipid matrix lets water leave faster than it is replaced.

Does drinking more water make skin less dry?
Adequate fluid intake is part of normal function, but dryness is mostly about how much water the barrier retains and the dermis holds. Drinking beyond your needs does not change either.

Does eaten collagen reach the skin?
Not intact. It is digested into peptides and amino acids like any other protein. Studies have asked whether a defined raw material at a defined daily dose is associated with measurable changes in the skin over time, which is what the Cartidyss® study measured.

Is sun exposure the main factor in skin ageing?
Sunlight generates reactive oxygen species in the dermis that damage lipids, proteins and DNA and accelerate collagen loss. It is the largest external contributor, alongside the internal changes that come with age.

How long does it take to see a difference?
Skin renews on its own timescale, and the studies behind the raw materials in Beauty Complete ran for two to three months. That is the horizon to plan for.

Do I need a supplement for healthy skin?
A varied diet, adequate fluid, sleep and sun protection are the foundation, and a supplement does not replace them. What it adds is defined raw materials at studied doses, every day. That is what Beauty Complete is for.

Sources

1. Varani J, et al. Decreased collagen production in chronologically aged skin. Am J Pathol. 2006.
2. Kawada C, et al. Ingested hyaluronan moisturizes dry skin. Nutr J. 2014.
3. Zague V, et al. Collagen peptides modulate the metabolism of dermal fibroblasts. J Med Food. 2011.
4. Pilkington SM, et al. Omega-3 polyunsaturated fatty acids, photoprotection and skin health. Dermatoendocrinol. 2011.
5. Rinnerthaler M, et al. Oxidative stress in aging human skin. Biomolecules. 2015.
6. Filaire E, et al. Age related changes in oxidative stress and SOD activity. Eur J Clin Invest. 2010.
7. Wlaschek M, et al. Inflammaging of the skin, the impact of oxidative stress and inflammation. Exp Gerontol. 2021.

Important information

This article is general information and educational reading. It is not medical advice and does not diagnose or treat any condition. Food supplements are not a substitute for a varied diet and a balanced lifestyle. If you are pregnant, breastfeeding, taking medication or have a medical condition, speak to a qualified healthcare professional before taking a supplement.