What Is Myreth-5?
Myreth-5 is a synthetic ingredient made by reacting fatty alcohols that come from coconut or palm oil with ethylene oxide. The result is a clear to pale yellow liquid that dissolves in both oil and water, making it a handy bridge between the two. First introduced in the 1970s, it quickly found a place in personal care labs looking for gentler alternatives to earlier detergents. Production starts with a mid-chain fatty alcohol, usually tetradecyl alcohol, that is run through a controlled ethoxylation process to attach an average of five ethylene oxide units, which is why the name ends in “-5.” Because the reaction conditions are tightly managed, manufacturers can create a consistent product batch after batch.
You will most often see Myreth-5 in rinse-off products like facial cleansers, body washes and shampoos, but it also shows up in leave-on formulas such as lightweight lotions makeup removers and some hair conditioning sprays. Its ability to keep water and oil mixed lets product developers load a formula with nourishing oils without the product separating on the shelf.
Myreth-5’s Cosmetic Benefits/Uses
In everyday skin and hair care, Myreth-5 serves one main purpose that makes many modern textures possible.
As an emulsifying agent it helps water and oil blend into a stable, uniform mixture. This prevents creams from splitting, keeps cleansing oils from feeling greasy and allows shampoos to rinse cleanly. By holding the formula together it also supports even delivery of active ingredients so each use feels the same from the first pump to the last.
Who Can Use Myreth-5
Because it is a gentle emulsifier, Myreth-5 is generally well tolerated by most skin types including oily, dry, combination and even sensitive skin. Those with extremely reactive or allergy-prone skin should still proceed with caution since any ethoxylated ingredient can occasionally trigger irritation in a small portion of users.
The ingredient is typically derived from plant oils such as coconut or palm rather than animal sources, making it suitable for vegans and vegetarians. As always, cruelty-free status depends on the overall supply chain and brand policy.
No data suggest that Myreth-5 poses special risks to women who are pregnant or breastfeeding when used topically in cosmetics. This is not medical advice and anyone who is expecting or nursing should review all personal care products with a qualified healthcare professional to be safe.
Myreth-5 is not known to cause photosensitivity, so it does not make skin more prone to sunburn. It also performs well across a broad pH range which helps keep formulas stable for users of all ages.
Potential Side Effects/Adverse Reactions
Reactions to topical Myreth-5 vary from person to person. The points below list potential side effects that could occur, but they are not expected for the average user when the ingredient has been properly formulated and used as directed.
- Mild skin irritation such as redness stinging or itching
- Dryness or tightness if used in very high concentrations
- Eye irritation if a product accidentally gets into the eyes
- Allergic contact dermatitis in individuals sensitive to fatty alcohol ethoxylates
If you notice any of these effects stop using the product and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 1 out of 5
Myreth-5 is a lightweight emulsifier that sits mostly on the surface of the skin and rinses away easily, so it does not have the heavy, pore-clogging character of thicker oils or waxes. Its ethoxylated structure makes it water loving, which lowers the chance of it lingering in pores. For these reasons the ingredient ranks low on the comedogenic scale.
People who are prone to acne or breakouts generally tolerate Myreth-5 well, especially when it appears in rinse-off cleansers or sprays.
Keep in mind that overall formula design plays a part. If Myreth-5 is blended with richer oils that do clog pores, the finished product’s breakout risk can be higher even though this single ingredient scores low.
Summary
Myreth-5 is mainly used as an emulsifier that keeps water and oil mixed so creams stay smooth, cleansers feel balanced and active ingredients are delivered evenly. It does this by having a fatty tail that loves oil and a short chain of ethylene oxide units that love water, positioning itself at the interface of the two and holding everything together.
You will spot Myreth-5 most often in everyday cleansers and body washes. It is not the trendiest emulsifier on today’s ingredient lists but formulators still rely on it because it is consistent, mild and affordable.
Safety data show low irritation potential for the vast majority of users when products are made correctly. As with any new cosmetic, doing a quick patch test on a small area of skin is a smart step to make sure the entire formula agrees with you before full use.