What Is Isosteareth-2?
Isosteareth-2 is a synthetic ingredient made by reacting isostearyl alcohol, a waxy fatty alcohol derived from vegetable oils or animal fats, with ethylene oxide to add two repeating ethoxy units. The result is a small, water-compatible molecule known technically as a polyethylene glycol ether. First introduced in the 1970s, it answered the growing need for versatile emulsifiers that could keep oil and water mixed in the new wave of lighter lotions and creams. Manufacture takes place in controlled reactors where the amount of ethylene oxide is carefully metered to achieve the “-2” designation, meaning exactly two ethoxy groups are attached.
You will most often spot Isosteareth-2 in facial cleansers, makeup removers, lightweight moisturizers, hair conditioners, clay or cream masks and some styling products. Its ability to bridge oil and water also makes it handy in tinted moisturizers and sunscreens where pigments or UV filters need to stay evenly dispersed.
Isosteareth-2’s Cosmetic Benefits/Uses
In formulas Isosteareth-2 serves two key roles that improve how a product looks, feels and performs on skin or hair
- Cleansing: It loosens and lifts away dirt, oil and makeup so they can be rinsed off without harsh scrubbing which helps leave skin feeling fresh but not stripped
- Emulsifying: It binds water with oils, silicones or waxes creating stable, smooth emulsions that resist separating during storage and glide evenly during application for a consistent user experience
Who Can Use Isosteareth-2
Because it is lightweight and non greasy Isosteareth-2 works for most skin types including oily balanced dry and combination. Its mild cleansing action means it is usually gentle enough for sensitive skin, though people with a known allergy to polyethylene glycols or fatty alcohols should proceed with caution.
The molecule itself is synthetic but its starting fatty alcohol can be sourced from either plants or animals. Most large manufacturers choose vegetable derived feedstocks so the finished material will often be suitable for vegans and vegetarians. If you follow a strict lifestyle philosophy it is still best to check with the individual brand regarding their sourcing policy and overall cruelty-free standards.
No data suggest that topical use poses a specific risk to women who are pregnant or breastfeeding. The ingredient is not absorbed in meaningful amounts through intact skin and it is not listed on any regulatory watchlists. That said this is not medical advice and anyone who is expecting or nursing should review all personal care products with a physician before use just to be safe.
Isosteareth-2 does not increase photosensitivity so you do not need to worry about extra sunburn risk. It is also odorless and free of essential oil components which makes it unlikely to interfere with fragrance allergies.
Potential Side Effects/Adverse Reactions
Reactions to topical Isosteareth-2 vary from person to person. The effects noted below are only potential outcomes. When the ingredient is used correctly in a well formulated product most people will not experience any problems.
- Mild skin irritation such as transient stinging or burning especially on compromised or freshly exfoliated skin
- Redness or flushing in individuals with very reactive skin
- Allergic contact dermatitis in rare cases where a person is sensitized to polyethylene glycols or trace impurities
- Eye irritation if a cleanser or cream accidentally gets into the eyes
- Follicular congestion in extremely acne prone users when the ingredient sits on skin for prolonged periods
If any of these effects occur discontinue use and consult a healthcare professional or dermatologist for further guidance.
Comedogenic Rating
Rating: 1/5. Isosteareth-2 is a small PEG-based emulsifier that is largely water compatible so it rinses away easily and does not sit heavily on the skin. Laboratory data and anecdotal reports show very few instances of pore clogging which keeps its score near the bottom of the scale. Because of this low rating the ingredient is usually considered suitable for people prone to acne or breakouts. Keep in mind that overall formula design and how long the product stays on the skin can influence individual experiences.
Summary
Isosteareth-2 works primarily as a mild cleanser and an emulsifier, meaning it helps lift away dirt and makeup while keeping the oily and watery parts of a formula perfectly blended. Its two ethoxy units provide just enough water loving character to make the ingredient rinse clean while still anchoring to oils, which is why formulators reach for it when they want light textures that leave no greasy film.
Although it is not a household name it appears in a steady stream of facial cleansers, makeup removers and lightweight creams, quietly doing the behind the scenes work that allows those products to feel silky and stay stable on the shelf.
Safety profiles from cosmetic regulators rate Isosteareth-2 as low risk with only rare cases of irritation or allergy. As with any new product it is smart to patch test first so you can be sure your skin agrees with the full formula.