Sodium N-Isostearoyl Methyltaurate: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Sodium N-Isostearoyl Methyltaurate?

Sodium N-isostearoyl methyltaurate is a mild cleanser made by linking two everyday building blocks: isostearic acid, a fatty acid usually taken from vegetable oils, and methyltaurine, an amino-acid-like molecule. Once these two are joined, the mix is neutralized with a small amount of sodium to create a water-friendly salt that blends easily into cosmetic formulas.

The ingredient first gained notice in the late 1990s when brands began looking for gentler, sulfate-free alternatives for face and body washes. Because it keeps skin feeling soft while still lifting away dirt and oil, chemists soon introduced it into a wide range of rinse-off products.

Today you will most often spot sodium N-isostearoyl methyltaurate in foaming facial cleansers, creamy body washes, low-lather shampoos, micellar waters, makeup-removing wipes, and even some clay or peel-off masks where a touch of cleansing action is needed.

Sodium N-Isostearoyl Methyltaurate’s Cosmetic Benefits/Uses

This ingredient is valued for one key role in skin and hair care products.

Cleansing: It acts as a gentle surfactant that loosens and lifts away sweat, excess oil, and everyday grime without stripping the skin or hair. Its fatty acid side helps protect the natural moisture barrier, so formulas feel creamy and leave a soft, conditioned finish rather than a tight, squeaky one.

Who Can Use Sodium N-Isostearoyl Methyltaurate

This mild surfactant is generally suitable for all skin types including sensitive, oily, combination and dry skin. Its fatty acid base helps prevent the tight, stripped feeling that harsher cleansers can cause, making it a good match even for easily irritated complexions. People with extremely compromised or allergy-prone skin should still review the full ingredient list of any product to rule out other potential triggers.

Sodium N-isostearoyl methyltaurate is typically derived from plant oils and synthesized without animal by-products, so formulas using the ingredient are usually vegan and vegetarian friendly. Always verify with the brand if animal-derived processing aids are a concern.

No data indicate that the ingredient poses a risk to women who are pregnant or breastfeeding when used topically in rinse-off products. This is not medical advice and anyone who is pregnant or nursing should confirm the safety of their entire skincare routine with a qualified healthcare provider.

The ingredient does not increase photosensitivity, so it will not make skin more prone to sunburn. Standard daily sun protection is still recommended for overall skin health.

Potential Side Effects/Adverse Reactions

Responses to topical Sodium N-isostearoyl methyltaurate vary from person to person. The points below list potential side effects although most users will not experience them when the ingredient is used correctly in a finished product.

  • Mild transient dryness or tightness, especially if the cleanser is highly concentrated or used very frequently
  • Temporary redness or stinging in very sensitive or compromised skin
  • Allergic contact dermatitis in individuals sensitive to fatty acid or taurine derivatives
  • Eye irritation if the formula accidentally gets into the eyes

If any of these effects occur stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1/5. Sodium N-isostearoyl methyltaurate is made from a highly branched fatty acid that does not pack tightly inside pores, and it is used at low levels in rinse-off products. These factors keep its likelihood of clogging pores very low.

Because of this low score the ingredient is generally fine for people who are prone to acne or breakouts.

As with any surfactant, the finished formula matters: heavy oils, waxes or butters added alongside it could raise the overall comedogenicity of the product even though the cleanser itself stays low.

Summary

Sodium N-isostearoyl methyltaurate is mainly a gentle cleansing agent. Its fatty portion anchors onto oils while the water-loving salt end lifts grime away, so skin and hair feel clean yet comfortable.

The ingredient gained steady popularity in the late 1990s as brands searched for sulfate-free options and it remains a quiet workhorse in modern gels, creams and micellar waters rather than a headline star.

Current data show it is safe for topical use in rinse-off formulas with only rare reports of irritation or allergy. As with any new skincare product, patch test first to confirm your skin agrees with the full formula.

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