Steareth-27: 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 Steareth-27?

Steareth-27 is a nonionic surfactant created by attaching about 27 ethylene oxide units to stearyl alcohol, a fatty alcohol that typically comes from vegetable oils like coconut or palm or from synthetic petrochemical routes. The result is a waxy, off-white solid that dissolves readily in both water and oil, letting it act as a bridge between the two. Ethoxylated fatty alcohols have been explored since the 1950s as safer, milder alternatives to soap in personal care, and Steareth-27 entered commercial use when formulators wanted a version with higher ethoxylation for better solubility.

Manufacturing starts with purified stearyl alcohol, which is fed into a reactor with ethylene oxide gas under controlled heat and pressure. Catalysts guide the reaction so that roughly twenty-seven ethylene oxide units attach to each molecule. After neutralization and filtration the finished ingredient is ready for blending into cosmetic bases.

You will usually find Steareth-27 in cleansers, micellar waters, facial masks, exfoliating scrubs, lotions, anti-aging serums, sunscreens, hair conditioners and makeup removers, where it helps disperse oils, pigments and active agents evenly through a formula.

Steareth-27’s Cosmetic Benefits/Uses

Below is how Steareth-27 contributes to a product’s performance

  • Cleansing: Its surfactant nature lifts dirt, excess sebum and makeup from skin or hair then helps them rinse away, giving a gentle yet effective clean without stripping natural moisture

Who Can Use Steareth-27

Steareth-27 is considered gentle enough for most skin types including dry, normal, oily, combination and sensitive skin because it cleans without leaving a harsh residue. Those with very reactive or compromised skin should still pay attention to how their skin feels, as any surfactant has the potential to cause temporary tightness or irritation if overused.

The ingredient itself is synthetic and contains no animal derived matter, so products that use Steareth-27 can fit vegan and vegetarian lifestyles as long as the rest of the formula is also free from animal ingredients.

No studies have linked Steareth-27 to problems during pregnancy or while breastfeeding. Though it is widely regarded as safe, this is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of any skin or hair product to a qualified doctor before use.

Steareth-27 does not increase the skin’s sensitivity to sunlight and it does not interfere with sunscreens. It also has no known interactions with common active ingredients such as retinol, vitamin C or hydroxy acids, so it blends well into multi-step routines.

Potential Side Effects/Adverse Reactions

Side effects from topical Steareth-27 vary from person to person. The points below describe potential reactions that could occur, but most users will not experience them when the ingredient is properly formulated and used as directed.

  • Mild skin irritation or stinging, especially on broken or freshly exfoliated skin
  • Redness or itching linked to sensitivity to ethoxylated ingredients
  • Contact dermatitis in individuals with a specific allergy to fatty alcohol ethoxylates
  • Eye irritation if the product accidentally gets into the eyes
  • Dryness when used in very high concentrations or paired with other strong cleansers

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

Comedogenic Rating

Rating: 1 / 5

Steareth-27 is a lightweight, water-soluble surfactant that usually appears in rinse-off formulas. Its ethoxylated structure lets it dissolve oils instead of sitting on the skin so it is unlikely to clog pores. Because it leaves minimal residue, most people prone to acne or breakouts can use products containing Steareth-27 without added risk.

Keep in mind that a finished product’s overall comedogenicity depends on the full blend of ingredients, texture and how thoroughly it is rinsed away.

Summary

Steareth-27 is mainly valued for its cleansing power and its ability to mix oil and water phases, helping a formula lift away dirt, makeup and excess sebum while keeping textures smooth and stable. It turns up in everything from micellar waters to conditioners, though it is not the most talked-about ingredient since it works quietly behind the scenes.

Current safety assessments rate Steareth-27 as low risk when used as directed, with only minor irritation possible for very sensitive users. As with any new cosmetic we suggest doing a quick patch test first, just to confirm your skin agrees with the product.

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