Your Skin Makes Its Own Moisturiser: NMF & Filaggrin Explained | ProJuvenate

If your skin feels tight by mid-afternoon, looks dull no matter how much you layer on, or flakes however rich the cream is, the problem probably is not what you are putting on. It is something your skin makes for itself, and has stopped making well.

It is called the natural moisturising factor, and it explains a great deal about why some skin holds water and some does not.

What is the natural moisturising factor?

The natural moisturising factor — NMF for short — is a mixture of water-loving compounds sitting inside the cells at the very surface of your skin.

Its job is simple: hold water where you want it. It keeps the surface hydrated, keeps the skin slightly acidic the way it should be, and keeps the barrier resilient enough to cope with weather, heating, air conditioning and everything else the day involves.

Think of it as your skin's own built-in moisturiser, made fresh, sitting inside every surface cell.

What is it made of?

Roughly 40% of it is amino acids — serine, glycine, alanine, histidine.

The rest is a blend you may recognise from ingredient lists, which is not a coincidence:

• PCA, derived from glutamic acid, with strong water-binding ability
• Lactic acid, a gentle exfoliant and humectant that helps hold the skin's pH
• Urea, around 7%, which softens keratin and holds moisture
• Inorganic salts, around 8% — potassium, calcium, magnesium, better known as electrolytes, which govern how water moves through the skin
• Sugars and organic acids, a small but steady share, helping retain water and balance pH

Every one of those turns up in skincare because your skin already uses it.

Where does it actually come from?

Here is the part most people never hear, and it is the reason surface products alone only get you so far.

Your NMF is made from a protein called filaggrin.

The process runs roughly like this. Deeper in the epidermis, in a layer called the stratum granulosum, your skin builds filaggrin and stores it as inactive granules — waiting. As skin cells travel upward toward the surface, they flatten and lose their nucleus. That triggers enzymes to release the filaggrin, which binds keratin fibres and helps each cell flatten into the tough, protective shape that forms your outer barrier.

Then the filaggrin itself breaks down — protein into peptides, peptides into amino acids. Those amino acids, together with the PCA and urea they convert into, are your natural moisturising factor.

So your NMF does not begin at the surface. It begins several layers down, and arrives at the surface as the end product of a chain. Which means anything that improves the chain improves the result.

Why does this go wrong?

Several reasons, and most will sound familiar.

Some people simply produce less filaggrin, and it is partly genetic. Reduced filaggrin production is one of the best-documented associations in skin science: it underlies ichthyosis vulgaris, the condition that produces persistently dry, scaly, flaky skin, and it is strongly linked to eczema and to dermatitis. People in this group also tend to react more readily to ingredients that others tolerate without trouble.

If that describes your skin, the barrier is where to start rather than where to finish. Impaired barriers are one of the most common things treated in clinic, and the work always begins in the same place — supporting filaggrin production rather than only sealing the surface.

For everyone else, the process slows with age. It also falters when the raw materials are short — not enough amino acids, ceramides or cholesterol to build with.

The visible result is a surface where cells start lifting away from each other rather than sitting flat. That does three things at once. Light scatters instead of reflecting, so skin looks dull. Products penetrate poorly, so everything you apply works less well. And repair takes longer, because the ingredients that would help cannot reach the depth where they are needed.

Dullness, tightness, flaking and products that seem to have stopped working are usually one problem, not four.

Which ingredients actually help?

The useful ones work on filaggrin production, not just surface hydration.

• Niacinamide increases ceramide production and stimulates filaggrin expression — it helps your skin make more of the protein in the first place.
• Vitamin A (retinoids) promotes cellular turnover and differentiation, which increases filaggrin production and sends better-formed cells to the surface.
• Vitamin C supports collagen and works as an antioxidant. Inflamed skin struggles to make filaggrin, so calming that state helps indirectly.
• Alpha hydroxy acids like lactic and mandelic acid encourage the surface cells to release and shed on time, which both improves texture and lets other actives get where they need to go.
• PCA supports the NMF directly as a core hydrating component.
• Peptides, copper GHK-Cu among them, stimulate production of key structural proteins and lipids.
• Zinc is involved in building filaggrin, supports healing and reinforces barrier function.
• Pre- and probiotics support the microbiome and reduce inflammation, which makes the whole process easier.

One thing worth adding: an ingredient only helps if it arrives. Amino acids, lactic acid and ceramides applied to the surface support the surface. To improve filaggrin production you need the formula to reach the stratum granulosum, which is a question of delivery system rather than ingredient list.

How we approach it

The short version of our formulating philosophy is that we would rather help your skin do its own job well than substitute for it.

For a compromised, red or reactive barrier, colloidal zinc with aloe vera and allantoin is where we would start. Zinc feeds filaggrin production, aloe calms and regenerates, and allantoin supports the even cell turnover that produces better surface cells. Calm skin has more resources to spare for its own maintenance.

The next step up is a ceramide- and omega-rich crème built around an active that restores ceramide content while protecting hydration and pH — strengthening the outer layer, improving epidermal thickness, and reducing oxidative stress substantially. It is a thicker texture, which is the ceramides and omegas doing their work. Worth knowing if you spend your days in air conditioning, artificial light, or moving between temperature extremes.

For hydration itself, multiple weights of hyaluronic acid with niacinamide covers both halves — water held at the surface, and niacinamide supporting filaggrin synthesis underneath it.

Alongside those, a bio-cellulose face and neck mask improves the quality of the surface cells themselves, and an antioxidant mist protects the process day to day, since filaggrin production is continuous and so is the oxidative stress working against it.

Frequently asked questions

What is the natural moisturising factor in skin? A mixture of water-binding compounds — amino acids, PCA, lactic acid, urea, salts and sugars — held inside the cells at the skin's surface. It keeps the surface hydrated, maintains a slightly acidic pH, and supports the barrier.

What is filaggrin, and why does it matter? A protein your skin makes and then deliberately breaks down. Its breakdown products become your natural moisturising factor, so filaggrin production sets the ceiling on how well your skin hydrates itself.

Can you rebuild the natural moisturising factor? You can support it. Ingredients applied at the surface supplement it directly, while niacinamide, retinoids and zinc work further down to improve filaggrin production. Both matter, and the second is what creates lasting change.

Why does my skin look dull even when I moisturise? When NMF is depleted, surface cells lift away from each other rather than lying flat. Light scatters off an uneven surface instead of reflecting cleanly, which reads as dullness — and no amount of surface moisturiser corrects the underlying structure.

Why do my products seem to have stopped working? A disrupted surface absorbs poorly. If the barrier is compromised, actives sit on top rather than penetrating, so everything in your routine underperforms. Restoring the barrier usually makes the rest of the routine work again.

Is there a link between filaggrin and eczema? Yes, and it is well established. Reduced filaggrin production is associated with eczema, dermatitis and ichthyosis vulgaris, because less filaggrin means less natural moisturising factor and a barrier that holds water poorly and lets irritants in more easily. Supporting barrier function is standard practice for this kind of skin, though anything persistent or severe warrants a GP or dermatologist alongside it.

Is dry skin the same as a damaged barrier? Not quite. Dry skin lacks oil; a compromised barrier cannot hold water or keep irritants out. They often occur together, but a damaged barrier needs repair rather than simply more moisturiser.

Shop the products in this article

• Relief Crème 50mL — colloidal zinc, aloe vera and allantoin for red, reactive or compromised skin. The starting point for barrier repair.
• ReDesign Crème 50mL — ceramide- and omega-rich, for strengthening the outer layer and protecting against environmental stress.
• B-Hydrated 4D 30mL — multiple molecular weights of hyaluronic acid with niacinamide, hydrating the surface while supporting filaggrin underneath.
• PhytoRenew Face & Neck Mask — bio-cellulose mask supporting barrier structure and surface cell quality.
• PhytoProtect 60mL — antioxidant mist for day-to-day protection against oxidative stress.

Not sure where to start? Find your nearest Juvenate clinic — a professional skin consultation will identify whether your barrier needs repairing before anything else.

This article is drawn from a clinic education session presented by Roxanne Rothman, Global Education and Growth Manager at ProJuvenate Skincare. Roxanne delivers ongoing ingredient and treatment training to skin clinics across New Zealand, Australia and the USA.