Isosteareth-22: 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 Isosteareth-22?

Isosteareth-22 is a man-made ingredient created by attaching about twenty two units of ethylene oxide to isostearyl alcohol, a fatty alcohol usually derived from plant oils such as coconut or rapeseed. The result is a waxy, off-white solid that dissolves easily in water and oil. Chemists call it poly(oxy-1,2-ethanediyl) .alpha.-isooctadecyl-.omega.-hydroxy-, but in product labels you will simply see Isosteareth-22.

The beauty industry began using this material in the late 1970s when formulators were looking for gentle alternatives to soap based surfactants. Its balanced oil-and-water loving structure made it ideal for modern creams and lotions, so it quickly found a home in moisturizers, face masks, serums, sunscreens and cleansing milks. Production relies on a process known as ethoxylation, where ethylene oxide gas reacts with purified isostearyl alcohol under heat and pressure. Careful control of the reaction time lets chemists stop at roughly twenty two ethylene oxide units, giving the ingredient a predictable thickness and feel.

Isosteareth-22’s Cosmetic Benefits/Uses

In skin and hair products Isosteareth-22 serves two main jobs that improve both performance and consumer experience

  • Cleansing – Its surfactant nature loosens makeup, excess oil and daily grime so they can be rinsed away without stripping the skin
  • Emulsifying – It helps water and oil blend into a smooth stable emulsion, preventing separation and giving creams a light, silky texture that spreads evenly

Who Can Use Isosteareth-22

Isosteareth-22 is considered gentle enough for most skin types including normal, dry, combination and oily skin. It has a very low likelihood of clogging pores so acne-prone users usually tolerate it as well. Those with highly sensitive or eczema-prone skin may want to watch for any personal irritation since the ingredient is still a synthetic surfactant, but reports of problems are rare.

The ingredient is typically made from plant-derived fatty alcohol and petroleum-origin ethylene oxide, and no animal by-products are used in the process. Because of this it is viewed as suitable for vegans and vegetarians.

Current safety reviews show no specific risks for people who are pregnant or breastfeeding when Isosteareth-22 is used in cosmetic amounts. This is not medical advice and anyone who is expecting or nursing should run all skincare choices past a qualified healthcare provider to be on the safe side.

Isosteareth-22 is not known to cause photosensitivity, so it will not make the skin more prone to sunburn. It can be used in both rinse-off and leave-on products without special daylight restrictions.

Potential Side Effects/Adverse Reactions

Side effects from topical use of Isosteareth-22 can vary from person to person. The points below list potential reactions, but they are rarely seen in the average user when the ingredient is included at normal cosmetic levels.

  • Mild skin irritation such as itching or burning, especially on highly sensitive skin
  • Temporary redness or a rash caused by contact dermatitis
  • Eye stinging or watering if a product containing the ingredient gets into the eyes
  • Allergic reaction that may show up as hives or swelling, though this is uncommon
  • Increased absorption of other active ingredients which could heighten their effects in rare cases

If any of these reactions occur stop using the product and consult a healthcare professional for guidance.

Comedogenic Rating

Rating: 1 / 5

Isosteareth-22 is highly water soluble and used at low levels, so it rinses off easily without leaving a heavy film that could block pores. Its molecular structure is larger than sebum constituents, making it less likely to lodge inside follicles. For these reasons formulators view it as having only a slight chance of clogging pores.

People who are prone to acne or breakouts generally tolerate Isosteareth-22 well, though each person’s skin can react differently.

Because it can raise the penetration of other ingredients, very oily or congested skin might prefer lighter formulas that pair it with non occlusive oils.

Summary

Isosteareth-22 works as a cleanser and emulsifier. Its surfactant part breaks the surface tension of oils and dirt so they lift away with water while the fatty alcohol side latches onto oils and keeps water and oil mixed. This gives creams and cleansers a smooth feel and keeps them from separating on the shelf.

The ingredient is moderately popular in everyday skincare like lotions cleansers and sunscreens but you will not see it hyped on front labels the way you might see more trendy actives. Chemists appreciate it for its reliability and silky finish which is why it still shows up in many quiet workhorse formulas.

Current data says Isosteareth-22 is safe for almost all users at cosmetic levels with only rare reports of mild irritation. As with any new skincare product a quick patch test on a small area is always a smart idea to make sure your skin agrees with it.

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