What Is Myreth-4?
Myreth-4 is a nonionic surfactant created by attaching an average of four ethylene oxide units to myristyl alcohol, a fatty alcohol most often sourced from renewable plant oils such as coconut or palm kernel. The result is a clear to pale yellow liquid that mixes easily with water and oil, making it valuable in modern cosmetic chemistry.
Ethoxylated fatty alcohols like Myreth-4 started appearing in personal care formulas in the mid 1900s when formulators sought gentler alternatives to traditional soaps. The manufacturing process begins with purified myristyl alcohol, which is reacted with ethylene oxide gas under controlled heat and pressure. By stopping the reaction after roughly four ethylene oxide additions, suppliers obtain the specific chain length that gives Myreth-4 its balance of mildness and emulsifying power.
Today you will most often find Myreth-4 in oil-in-water emulsions where a silky skin feel and dependable stability are needed. Typical product categories include facial cleansers, lightweight lotions, sunscreens, makeup removers, leave-on hair conditioners, sheet masks and occasional anti-aging serums.
Myreth-4’s Cosmetic Benefits/Uses
In cosmetics Myreth-4 serves one primary job that unlocks several formulation advantages.
As an emulsifying agent it helps water and oil blend into a uniform, stable mixture. This keeps a lotion from separating on the shelf, allows makeup removers to lift away long-wear pigments and lets sunscreens spread evenly so their protective ingredients form a consistent film. Its mild nature also supports gentle cleansers that leave skin soft rather than stripped.
Who Can Use Myreth-4
Because it is a mild nonionic surfactant, Myreth-4 is generally suitable for normal, dry, oily and combination skin. Sensitive skin usually tolerates it well, though people prone to redness or a compromised skin barrier might prefer formulas that keep its concentration low to minimize any chance of irritation.
Most commercial sources obtain the myristyl alcohol used to make Myreth-4 from coconut or palm kernel oil, so products containing it are typically vegan and vegetarian friendly. To be absolutely certain strict vegans should confirm the supplier’s origin statement on finished products.
Available safety data shows no specific hazards for pregnant or breastfeeding women when Myreth-4 is used topically at cosmetic levels. That said this is not medical advice and anyone who is pregnant or nursing should review all skincare products with a qualified healthcare provider before use just to be safe.
Myreth-4 is not known to cause photosensitivity and does not interact with UV light, so it will not make skin more prone to sunburn. No additional special considerations are currently known for its use in hair or body care products.
Potential Side Effects/Adverse Reactions
Responses to topical Myreth-4 vary from person to person. The issues listed below are only potential side effects and are unlikely for most users when the ingredient is used correctly by the product manufacturer.
- Mild skin irritation – stinging or redness can occur in very sensitive individuals, especially if the product is left on the skin for long periods
- Contact dermatitis – rare allergic reactions with rash or itching have been reported, typically in people with multiple surfactant sensitivities
- Dryness or tightness – high levels in cleansers may strip natural oils leading to a temporary feeling of dryness
- Eye irritation – accidental contact can cause watering or a burning sensation until rinsed out
- Enhanced penetration of other ingredients – as a surfactant it can increase skin permeability, which could amplify the effects of potent actives in the same formula
If any unwanted reaction develops stop using the product and seek advice from a healthcare professional or pharmacist.
Comedogenic Rating
Myreth-4 carries a comedogenic rating of 1 on the 0-5 scale. Its parent fatty alcohol myristyl alcohol is more pore-clogging, but the addition of ethylene oxide units increases water solubility and greatly lowers the chance that it will build up inside follicles. Most formulations include it at low to moderate levels where it rinses or absorbs cleanly without leaving a heavy residue. Because the rating sits at the lower end of the scale, Myreth-4 is generally considered fine for people who are prone to breakouts, provided the rest of the product is also non-comedogenic. No data suggest it aggravates fungal acne, and it is easily removed with standard cleansing routines.
Summary
Myreth-4 is a mild nonionic surfactant that mainly serves as an emulsifier, helping water and oil stay mixed so lotions remain smooth, cleansers rinse evenly and sunscreens form a uniform protective film. Its balance of oil-loving and water-loving parts lets it do this job without harshness, giving formulas a light non-greasy feel.
While not a headline ingredient, Myreth-4 is a quiet workhorse found in many mid-range and mass-market products where formulators need reliable stability at a reasonable cost. It tends to fly under the radar yet shows up on countless ingredient lists in cleansers, moisturizers and sunscreens.
Current research and decades of safe use suggest Myreth-4 is low risk for irritation or allergy when used at cosmetic levels. Still, everyone’s skin is different so it is smart to patch test any new product that contains it just to ensure personal tolerance.