What Is Isomyreth-3?
Isomyreth-3 is the cosmetic name for polyoxyethylene (3) isomyristyl ether, a compound made by attaching three units of ethylene oxide to isomyristyl alcohol, a fatty alcohol related to myristic acid that is commonly sourced from coconut or palm kernel oil. This process, called ethoxylation, changes the raw fatty alcohol into a water-friendly ingredient that mixes easily with both oils and water. Chemists began using this type of material in the mid-20th century when the beauty industry needed gentler alternatives to harsh soaps. Because Isomyreth-3 can grab on to oil and dirt while still rinsing away with water, it quickly found a place in face washes, shower gels, and even micellar waters. Its ability to keep oil and water blended also makes it valuable in lotions, cream cleansers, makeup removers, hair conditioners, sheet masks, and lightweight moisturizing gels.
Isomyreth-3’s Cosmetic Benefits/Uses
In formulas Isomyreth-3 serves two main jobs that improve both product performance and user experience
- Cleansing: It loosens makeup, excess sebum, and daily grime so they can be rinsed away without stripping the skin or hair. This leaves the surface feeling fresh and comfortable rather than tight.
- Emulsifying: It helps water and oil stay mixed, giving creams and lotions a smooth stable texture that does not separate on the shelf. This consistent blend also ensures that active ingredients are spread evenly with each use.
Who Can Use Isomyreth-3
Isomyreth-3 is generally well tolerated by most skin types including normal, oily, combination and dry skin. Its mild cleansing action means it rarely causes the tight feeling that harsher surfactants can leave behind, which makes it a good choice for sensitive or mature skin as well. Those with very reactive or eczema-prone skin should still watch for any personal irritation since every skin barrier is different.
The ingredient is made from plant-derived fatty alcohols and synthetic ethylene oxide, so it is suitable for both vegans and vegetarians. No animal-based raw materials or by-products are used in its standard production process.
Available safety data shows no specific risk linked to pregnancy or breastfeeding when the ingredient is used in rinse-off or leave-on cosmetics. Still, this is not medical advice and anyone who is pregnant or nursing should review new skincare products with a doctor to be extra cautious.
Isomyreth-3 does not make skin more sensitive to sunlight and it is not known to interfere with sunscreen performance. It also plays well with common actives like vitamin C, niacinamide and most acids, so routine layering worries are minimal.
Potential Side Effects/Adverse Reactions
Reactions to topical Isomyreth-3 vary from person to person. The points below list possible but uncommon side effects. When used at the levels set by cosmetic guidelines most users will not experience these issues.
- Skin irritation Mild redness stinging or itching can occur on very sensitive skin especially if the formula contains a high percentage of surfactants
- Contact dermatitis A small number of people may develop a localized rash due to an allergy to the ingredient or to impurities left from processing
- Eye irritation If a cleanser with Isomyreth-3 gets into the eyes it may cause temporary burning or watering
- Dryness Over-cleansing with any surfactant can disrupt the natural oil balance leading to a feeling of dryness or flakiness
If you notice any unwanted reaction stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1/5
Although Isomyreth-3 comes from a fatty alcohol related to myristic acid, turning it into a polyoxyethylene ether makes it highly water friendly so it rinses off instead of lingering in pores. It is usually used at low to moderate levels in wash-off cleansers or light lotions, leaving almost no residue. Because of this its pore-clogging potential is considered very low.
Suitable for acne-prone or breakout-prone skin.
This low rating applies to typical formulations. If paired with heavy oils in a rich leave-on cream the finished product could still feel occlusive for very oily skin types.
Summary
Isomyreth-3 acts as a mild cleanser and an emulsifier. One end grabs oil and grime while the other mixes with water, letting cleansers lift debris without stripping and helping lotions stay smooth and uniform.
It is not a headline-grabbing ingredient but its reliability keeps it in many face washes, micellar waters and lightweight creams sold today.
Safety data shows it is generally gentle and low risk when used within cosmetic guidelines, yet it is still wise to patch test any new product that contains it to be sure your skin agrees.