Trideceth-8: 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 Trideceth-8?

Trideceth-8 is a synthetic ingredient made by attaching about eight units of ethylene oxide to a fatty alcohol that has 13 carbon atoms. This process is called ethoxylation and it turns an oily substance into one that can mix with both water and oil. The fatty alcohol base often comes from petroleum or natural fats, then goes through controlled chemical steps in a factory setting. Chemists began adding ethoxylated fatty alcohols like Trideceth-8 to personal care items in the late twentieth century when the need for gentle yet effective cleansers grew. Today Trideceth-8 is common in rinse-off formulas such as face washes, body washes and shampoos, as well as leave-on products such as lotions, creams and makeup removers where it helps blend oil and water into a smooth texture.

Trideceth-8’s Cosmetic Benefits/Uses

In skin and hair care formulas Trideceth-8 serves important technical roles that improve how a product looks, feels and performs on the body.

  • Cleansing. Trideceth-8 lowers the surface tension of water so dirt, excess oil and residues can be lifted away more easily during rinsing. This helps cleansers foam lightly and leave skin or hair feeling fresh without a tight after-feel.
  • Emulsifying. By linking water loving and oil loving parts in one molecule, Trideceth-8 keeps oil and water mixed evenly. This prevents creams, lotions and liquid makeup from separating, giving a stable, smooth texture throughout the shelf life.

Who Can Use Trideceth-8

Because it is a mild cleansing and emulsifying agent, Trideceth-8 is generally suitable for normal, oily, combination and even sensitive skin types. Dry or eczema-prone skin may find very foamy formulas that contain higher amounts of Trideceth-8 a bit dehydrating, so opting for products where it appears lower on the ingredient list is wise.

The ingredient is synthesized in a lab from fatty alcohols that can come from petroleum or plant sources, with no animal-derived components needed, so it is typically acceptable for vegans and vegetarians. Certifications vary by brand, so anyone following a strict lifestyle should still look for a clear vegan label.

Current cosmetic safety assessments consider Trideceth-8 safe for use while pregnant or breastfeeding because it stays on the surface of skin and is not expected to enter the bloodstream in meaningful amounts. This is not medical advice and anyone who is pregnant or nursing should check with a healthcare professional before starting a new product just to be sure.

Trideceth-8 is not known to increase photosensitivity, so routine sun exposure precautions are all that is needed. It also plays well with most other common cosmetic ingredients, making it a flexible choice in multi-step routines.

Potential Side Effects/Adverse Reactions

Responses to topical Trideceth-8 vary by individual. The points below outline possible side effects, yet most users will not notice any problems when the ingredient is used correctly in a finished product.

  • Skin dryness or tightness
  • Transient stinging or redness, especially on very sensitive skin
  • Allergic contact dermatitis in rare cases
  • Eye irritation if the product accidentally gets into the eyes
  • Possible trace contamination with 1,4-dioxane or ethylene oxide if manufacturing is poorly controlled, though reputable brands keep levels far below safety limits

If any irritation, persistent redness or discomfort occurs stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1/5. Trideceth-8 is water soluble and acts primarily as a cleansing and emulsifying agent, so it does not linger in pores or leave a heavy, occlusive film that could trap sebum and debris. Its low oil content and quick rinse-off nature keep the risk of clogged pores minimal, making it generally suitable for acne-prone or breakout-prone skin. People extremely sensitive to any surfactant may still prefer spot-testing but for most users the ingredient poses little comedogenic concern.

Summary

Trideceth-8 works as a mild cleanser and an effective emulsifier by lowering surface tension and binding water with oil, which lets formulas stay uniform and rinse cleanly from skin or hair. It shows up in many everyday products like face washes, shampoos, lotions and makeup removers, though it is not the trendiest name on labels compared with newer plant-based surfactants.

Safety assessments rate it as low risk when formulated correctly, with irritation uncommon and comedogenicity low. Still, skin can be unpredictable so doing a quick patch test with any new product containing Trideceth-8 is a smart habit.

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