Isostearamide Dea: 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 Isostearamide Dea?

Isostearamide Dea is the cosmetic shorthand for N,N-bis(2-Hydroxyethyl)isooctadecan-1-amide, an amide derived from isostearic acid, a fatty acid usually sourced from vegetable oils such as rapeseed or soybean. By reacting isostearic acid with diethanolamine under controlled heat and vacuum, chemists produce a creamy, viscous compound prized for its texture-enhancing properties. The ingredient gained popularity in the late twentieth century when formulators searched for plant-based alternatives to animal fats and petroleum derivatives that could stabilize foams and improve product feel. You will most often spot it in shampoos, conditioners, shower gels, facial cleansers, bubble baths, shaving creams and occasionally in body lotions that need a richer, silkier glide.

Isostearamide Dea’s Cosmetic Benefits/Uses

This ingredient pulls its weight in several ways within a formulation:

  • Antistatic: Helps reduce static electricity on hair strands so styles stay smoother and less flyaway
  • Cleansing: Loosens and lifts away dirt oil and buildup allowing rinse-off products to purify skin or hair more effectively
  • Foam Boosting: Enhances the volume and stability of lather giving shampoos and washes that satisfying rich foam consumers expect
  • Viscosity Controlling: Thickens formulas to the ideal consistency creating products that feel luxurious yet still dispense easily

Who Can Use Isostearamide Dea

Because it is a non-active texturizer rather than a potent treatment ingredient, Isostearamide Dea tends to agree with most skin and hair types including normal, dry, oily and combination. Those with very sensitive or compromised skin can generally tolerate it as well, but if you know you react to amide or ethanolamine compounds it may be best to steer clear.

The ingredient is sourced from plant-derived fatty acids so it is suitable for vegans and vegetarians. No animal by-products are used in its manufacture.

Current research has not flagged Isostearamide Dea as a risk for pregnancy or breastfeeding when used topically in rinse-off products. Out of an abundance of caution this is not medical advice and anyone who is pregnant or nursing should show their chosen products to a healthcare professional first.

Isostearamide Dea does not increase photosensitivity and there are no known interactions with sun exposure. It is also fragrance-free and non-volatile so it will not contribute to strong scents or airborne irritation.

Potential Side Effects/Adverse Reactions

Individual responses to topical ingredients vary. The following list covers potential but uncommon reactions that might occur when using Isostearamide Dea. In correctly formulated products most people experience none of these issues.

  • Mild skin irritation in those with pre-existing sensitivity to amide or ethanolamine compounds
  • Contact dermatitis presenting as redness or itching if an allergy is present
  • Eye irritation if the ingredient gets into the eyes at higher concentrations such as in shampoo suds
  • Buildup on hair leading to a weighed-down feel if heavily formulated products are not rinsed thoroughly
  • Impurity concerns trace levels of residual diethanolamine (DEA) could theoretically form nitrosamines in formula but reputable manufacturers minimize this through purification and strict quality control

If any discomfort or reaction develops stop use immediately and consult a qualified healthcare professional for guidance.

Comedogenic Rating

Rating: 1 / 5

Isostearamide Dea is a fatty acid derivative but it is highly water dispersible and most often used in rinse-off cleansers and shampoos. Because it does not stay on the skin for long and its molecular structure is bulky, it sits low on the clogging scale. People who are prone to acne usually tolerate it without new breakouts.

The only caveat is leave-on formulas; if a rich lotion contains a high level of this ingredient and is not removed, susceptible users might notice minor congestion over time.

Summary

Isostearamide Dea thickens, boosts foam, reduces static and helps cleanse by loosening grime. It achieves these tasks thanks to its dual water-loving and oil-loving parts which let it sit at the water–oil interface, stabilize bubbles and add creamy body to products.

While not the trendiest buzzword on shelves, it remains a workhorse in many mainstream shampoos and body washes where consumers expect rich lather without animal or petroleum inputs.

The safety profile is solid; irritation or clogging is rare when formulas are made responsibly. As with any new cosmetic it is wise to patch test first to make sure your skin plays nicely.

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