Tea-Isostearate: 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 Tea-Isostearate?

Tea-Isostearate is a compound made by reacting isostearic acid, a fatty acid that can come from plant oils, with triethanolamine (often shortened to TEA), a clear liquid derived from reacting ethylene oxide with ammonia. The result is a salt that mixes the oily part of isostearic acid with the water-friendly part of triethanolamine, creating a balanced ingredient that works well in many personal care formulas.

This pairing first showed up in cosmetics in the late 20th century when chemists looked for gentler replacements for harsher soaps. By combining a soft fatty acid with a mild amine like TEA, they produced a cleanser that felt smoother on skin and hair. Over time its usefulness expanded from simple cleansers to more advanced creams and conditioners.

The manufacturing process is straightforward: purified isostearic acid is blended with triethanolamine in a controlled setting until the two reach a 1:1 ratio and form Tea-Isostearate. The mixture is then cooled, tested for purity and shipped as a thick liquid or soft paste.

You will most often spot Tea-Isostearate in face washes, micellar waters, scalp scrubs, lightweight moisturizers, two-phase makeup removers and hair masks. It is also popular in rinse-off body cleansers and creamy body lotions where a silky, non-greasy finish is desired.

Tea-Isostearate’s Cosmetic Benefits/Uses

Formulators turn to Tea-Isostearate for a few key reasons that improve how a product feels and performs.

  • Cleansing: The dual nature of the molecule lets it lift away dirt, oil and makeup while staying mild on skin. It helps water rinse these impurities off without leaving a tight, squeaky feel.
  • Hair conditioning: Its fatty acid tail smooths the hair cuticle which can reduce frizz and make strands easier to comb. This adds slip to conditioners and masks so hair feels softer after rinsing.
  • Emulsifying: Tea-Isostearate keeps oil and water phases blended in creams, lotions and two-phase cleansers. A stable emulsion means the product will not separate on the shelf and will spread evenly when applied.

Who Can Use Tea-Isostearate

Tea-Isostearate is generally well tolerated by most skin types including normal, dry, combination and oily skin because its fatty acid portion is softening while the TEA portion is mild and water loving. Sensitive skin users usually do fine with it since it is less irritating than many traditional surfactants, though anyone highly reactive to amines should read labels carefully.

The ingredient is synthesized from plant based isostearic acid and petro-derived triethanolamine, so it contains no animal components and is considered suitable for vegetarians and vegans. Look for cruelty-free certification on the finished product if that is important to you.

Pregnant or breastfeeding women have no special restrictions related to Tea-Isostearate because it stays on the skin surface and is not known to penetrate deeply or act hormonally. That said this is not medical advice and anyone expecting or nursing should show their doctor the full ingredient list of any product they plan to use.

Tea-Isostearate does not make skin more sensitive to the sun and can be safely paired with daytime routines that include sunscreen.

It is also compatible with most other common skincare ingredients so formulators can blend it into cleansers moisturizers or hair products without concern for unexpected interactions.

Potential Side Effects/Adverse Reactions

Individual responses to any cosmetic ingredient can differ. The following is a list of potential side effects tied to topical Tea-Isostearate use, though they are uncommon when the ingredient is included at standard cosmetic levels and manufactured correctly.

  • Mild skin irritation in people extremely sensitive to surfactants or amines
  • Eye stinging if a cleanser containing Tea-Isostearate is not fully rinsed out
  • Allergic contact dermatitis in rare cases where a person is allergic to triethanolamine derivatives
  • Build-up on very fine hair leading to a weighed-down feel if used in heavy leave-in products

If any redness itching or other discomfort appears stop using the product and seek advice from a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 1/5

Tea-Isostearate comes from a branched fatty acid that is less occlusive than straight chain oils and it is partially water soluble, so it rinses away instead of lingering on the skin. It is normally used at low levels in wash-off products, which further limits any pore-clogging risk.

Most people who are prone to acne or breakouts can use products with Tea-Isostearate without problems.

The overall formula still matters, so very heavy creams that pair it with thick waxes or butters could feel more comedogenic even if the ingredient itself is low risk.

Summary

Tea-Isostearate works as a gentle cleanser, an emulsifier that keeps oil and water blended and a light conditioner that smooths hair or softens skin. Its dual nature lets the fatty part latch onto grime while the water-loving part helps everything rinse clean.

It is a helpful but niche ingredient, appearing mainly in modern micellar waters, mild face washes, two-phase makeup removers and select hair masks rather than in every drugstore product.

Overall it scores well for safety with only rare reports of irritation or allergy. Even so, skin can react unpredictably so it is smart to patch test any new product that lists Tea-Isostearate to make sure it suits your individual skin.

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