Isosteareth-10 Stearate: 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
Share:
Inside this article:

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-10 Stearate?

Isosteareth-10 Stearate is a lab-made ingredient created by joining stearic acid, a fatty acid often sourced from vegetable oils, with ethylene oxide units and an isostearyl alcohol base. The result is a waxy, off-white substance that blends easily with both water and oil. Chemists first explored this class of ingredients in the mid-20th century while looking for gentler alternatives to harsh soaps. Over time its reliable performance and mild feel led to wide use in skin care and hair care formulas.

The production process begins with plant-derived stearic acid and isostearyl alcohol. These two are reacted to form an ester, then treated with about ten units of ethylene oxide per molecule. Each step is carefully controlled to remove impurities so the final material meets cosmetic safety standards.

Because it can balance water and oil, Isosteareth-10 Stearate shows up in many personal care products. You will find it in facial moisturizers, lotions, anti-aging creams, cleansing milks, makeup removers, sunscreens, leave-on hair treatments and sheet masks. Its soft texture and light finish make it useful anywhere a smooth, non-greasy feel is desired.

Isosteareth-10 Stearate’s Cosmetic Benefits/Uses

This multitasking ingredient earns its spot on an ingredient list by improving both product texture and skin feel.

  • Skin conditioning: Forms a thin, flexible layer that helps skin feel softer and look smoother after application
  • Emollient: Fills in tiny gaps between skin cells so the surface feels supple and less rough
  • Emulsifying: Keeps water and oil mixed together, giving creams and lotions a stable, uniform consistency that does not separate over time

Who Can Use Isosteareth-10 Stearate

Isosteareth-10 Stearate is generally considered friendly for every major skin type. Dry and mature skin benefit from its emollient smoothing while normal and combination skin appreciate its lightweight non greasy feel. Even oily or acne prone skin tends to tolerate it because it does not add heavy oil or trap excessive sebum.

The ingredient is usually sourced from plant based stearic acid and isostearyl alcohol so it is commonly suitable for vegans and vegetarians. If animal origin matters to you double-check the brand’s sourcing statement since stearic acid can also come from tallow.

No data link this ingredient to problems during pregnancy or breastfeeding. It is externally applied and not known to penetrate deeply but this is not medical advice. Anyone who is pregnant or nursing should show the full product label to a qualified health professional before use.

Isosteareth-10 Stearate does not increase photosensitivity so it will not make skin more prone to sunburn. It also works across a wide pH range and plays well with most other cosmetic ingredients so there are no special daytime or formulation restrictions to worry about.

Potential Side Effects/Adverse Reactions

Responses to any cosmetic ingredient can differ person to person. The effects listed below are only potential outcomes and most users will not experience them when the product has been properly formulated and preserved.

  • Mild skin irritation: transient redness or stinging on very sensitive or compromised skin
  • Allergic contact dermatitis: rare cases of itch or swelling if someone is specifically allergic to polyethylene glycol derivatives
  • Eye irritation: possible watering or burning if a product containing the ingredient gets directly into the eyes
  • Pore congestion: unlikely but possible in individuals extremely prone to comedones when used in very heavy formulations
  • Interaction with damaged skin: open cuts or severe eczema may allow deeper penetration leading to greater irritation

If you notice any persistent discomfort stop using the product and seek advice from a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 1 / 5

Isosteareth-10 Stearate has a low molecular weight portion that can rinse away yet its fatty acid part is light and spreadable rather than heavy and occlusive. Most safety panels and formulator handbooks list similar PEG-esters as minimally pore clogging which is why it earns a 1 rather than a 0. In real-world use it rarely builds up inside follicles unless the overall formula is already rich in waxes or butters.

Because of this low score it is usually fine for skin that tends to break out, especially when included in lightweight lotions or gels.

As with any ingredient, the finished product’s full recipe, thickness and rinse-off profile can raise or lower the risk so pay attention to how your skin reacts to the whole formula, not just the single component.

Summary

Isosteareth-10 Stearate acts as a skin conditioner, emollient and emulsifier. Its ester backbone softens rough patches while the attached ethylene oxide units help blend water with oils giving creams a smooth stable texture that feels light after application.

It is a workhorse rather than a headline maker so you will spot it more in everyday moisturizers and cleansers than in trendy marketing campaigns. Still, chemists value it for its reliability and pleasant skin feel which keeps it in steady demand.

Safety assessments classify it as low risk for irritation or sensitization when used at typical levels and good manufacturing removes any residual impurities. Even so, everyone’s skin is unique so try a small patch first whenever you introduce a new product containing this ingredient just to be cautious.

Was this article helpful?
More from Glooshi:
ADVERTISEMENT
Get all our top headlines in beauty.
Delivered right to your inbox each week. Zero spam, all goodness, opt-out at anytime.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Get the latest beauty news, top product recommendations & brand-exclusive discount codes direct to your inbox.
Send good feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Send bad feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Search