Natural Moisturizing Factor (NMF)

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What Is Natural Moisturizing Factor (NMF)?

Natural moisturizing factor, or NMF, is the skin's own mix of small, water-attracting molecules that sits inside the cells of the outermost layer of skin, the stratum corneum. It is made mostly of free amino acids and their derivatives, such as PCA (pyrrolidone carboxylic acid) and urocanic acid, plus lactate, urea, sugars, and mineral salts. These molecules pull in and hold water, which keeps the skin's surface soft, flexible, and smooth.

In skincare, "NMF ingredients" are cosmetic versions of those same molecules, such as sodium PCA, sodium lactate, urea, and amino acids, added to moisturizers to help replace what washing, dry air, sun, and age deplete.

Quick Facts

What it is A group of humectant molecules, not one ingredient
Where it comes from in skin The breakdown of filaggrin, a protein in the skin's outer layer
How much is there About 10% of corneocyte mass and 20% to 30% of the dry weight of the stratum corneum
Common INCI names on labels Sodium PCA, PCA, Sodium Lactate, Lactic Acid, Urea, amino acids (such as Serine, Glycine, Alanine, Arginine), Trehalose, Sodium Chloride
Form Mostly water-soluble powders or clear liquids
Solubility Water phase
Typical usage rate Sodium PCA: 2% to 8% (supplier range). Other NMF ingredients: follow each supplier's range
Skin types All, especially dry, dehydrated, mature, and over-washed skin

How NMF Works on the Skin

Skin cells in the deeper layers of the epidermis make a protein called profilaggrin. As cells move up and flatten into the stratum corneum, it is converted to filaggrin and then broken down into free amino acids and their derivatives. Those breakdown products account for 70% to 100% of the free amino acids found in the stratum corneum. Together with lactate, urea, and salts, they form NMF.

NMF works as a built-in humectant. It binds water inside the corneocytes, while the lipids between the cells (ceramides, cholesterol, and fatty acids) slow water loss. Rawlings and Harding (Dermatologic Therapy, 2004) described skin moisturization as the work of these two systems together: NMF holding water inside the cells and lipids sealing the spaces between them.

What depletes NMF

  • Washing. NMF is water soluble, so soap and long, hot showers rinse it out of the top layers of skin.
  • Low humidity. Dry air slows the enzymes that turn filaggrin into NMF.
  • Sun exposure. UV light impairs the breakdown of filaggrin into NMF.
  • Age. Mature skin makes less profilaggrin and has lower amino acid levels in the stratum corneum.

Skin with less NMF tends to look and feel rough, tight, and flaky, and fine lines look more pronounced when the surface is dehydrated.

What the research measured

In a 2024 study in the Journal of Drugs in Dermatology (Baldwin, Arrowitz, and Del Rosso), two double-blind comparisons with 35 and 33 participants tested ceramide moisturizers enriched with NMF against a ceramide-only cream on the lower legs for 10 days, followed by 5 days without moisturizer. Skin hydration measured by corneometer rose more with the NMF-enriched formulas at day 10 and day 15. In other words, adding NMF ingredients to a barrier cream gave a measurable hydration boost over lipids alone.

How to Use NMF Ingredients in Formulas

  • Add them to the water phase. Sodium PCA, sodium lactate, amino acids, and trehalose all dissolve easily in water. Urea is heat sensitive, so add it below 40°C (104°F) in the cool-down phase.
  • Use a blend. Your skin's NMF is a mixture, and blends of several NMF ingredients mimic it better than a single humectant.
  • Pair with lipids. Humectants pull in water; occlusives and barrier lipids keep it there. Combine NMF ingredients with ceramides, squalane, or a light oil.
  • Watch the pH. Keep finished products around pH 4.5 to 5.5, close to skin's natural surface pH. Sodium lactate and urea can shift pH, so test after adding them.
  • Preserve and store. NMF ingredients are water based and support microbial growth in a finished product, so use a broad-spectrum preservative and airless or pump packaging.
  • Apply to damp skin. Use NMF-rich products right after cleansing, when skin is still slightly damp, then follow with a moisturizer.

Who NMF Ingredients Suit

NMF ingredients suit every skin type, and they are especially helpful for dry, dehydrated, mature, and frequently washed skin. Even oily skin can be dehydrated, and lightweight NMF serums hydrate without heaviness. If you have sensitive skin, patch test first on the inner arm for 24 hours and start at the lowest rate of the range (for sodium PCA, 2%), then work up. Higher levels of urea and lactate can tingle on very dry or compromised-feeling skin.

Frequently Asked Questions

What are NMFs in skincare?

NMF ingredients are cosmetic versions of the molecules your skin uses to hold water, such as sodium PCA, sodium lactate, urea, and amino acids. They are added to moisturizers and serums to replace what washing, dry air, and age remove. On labels they usually appear as individual ingredients rather than the word NMF.

What does natural moisturizing factor do for the skin?

NMF binds water inside the cells of the skin's outer layer, which keeps the surface soft, flexible, and smooth. Lipids such as ceramides then slow the loss of that water. When NMF runs low, skin tends to look and feel rough, tight, and flaky.

How can I increase my skin's NMF?

Use gentle cleansers and lukewarm water, keep showers short, and moisturize within a few minutes of washing. Choose products that contain NMF ingredients plus barrier lipids, and use daily sunscreen, since UV light impairs the breakdown of filaggrin into NMF.

Are NMF ingredients suitable for all skin types?

Yes. They hydrate without heaviness, so they work for oily and combination skin as well as dry and mature skin. Higher levels of urea and lactate can tingle on very dry skin, so patch test first.

Is hyaluronic acid part of NMF?

No. Hyaluronic acid is found mainly in the deeper layers of skin and is not part of the stratum corneum's NMF. It works well alongside NMF ingredients. See our hyaluronic acid glossary entry.

What is the difference between NMF and ceramides?

NMF holds water inside skin cells, while ceramides are lipids that fill the spaces between cells and slow water loss. A good moisturizer supplies both. Learn more in our ceramides glossary entry.

Is dehydrated skin the same as dry skin?

Not quite. Dry skin lacks oil, while dehydrated skin lacks water, and even oily skin can be dehydrated. For more, read Dehydrated Skin: Best Hydration Tips.

Shop This Collection

For a daily hydrating step, the Ageless Advanced Peptide Moisturizer pairs hyaluronic acid with Matrixyl Synthe'6 and Syn-Coll for normal to mature, dry skin. Layer it over a peptide serum such as the Super Peptide Anti-Aging Serum.

Sources

  • Rawlings AV, Harding CR. Moisturization and skin barrier function. Dermatol Ther. 2004;17 Suppl 1:43-48. PubMed
  • Baldwin HE, Arrowitz C, Del Rosso J. Natural Moisturizing Factor-Enriched Formulations Compared to a Ceramide-Based Cream. J Drugs Dermatol. 2024;23(3):141-145. doi:10.36849/JDD.8172. JDD
  • Understanding the Role of Natural Moisturizing Factor in Skin Hydration. Practical Dermatology. July 2012. Practical Dermatology
  • Spec-Chem, Ingredients Catalogue 2026 V1, SpecKare PCAN (Sodium PCA) entry (supplier data: 2.0% to 8.0% usage rate).

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

About the Author
Written by Kari Thomas, cosmetic formulator and founder of Skin Perfection.