What Is Myristoyl Ethyltrimonium Methosulfate?
Myristoyl Ethyltrimonium Methosulfate is a quaternary ammonium compound created from myristic acid, a fatty acid that naturally occurs in coconut and palm kernel oils. Chemists combine myristic acid with an ethanol-based chain, then quaternize the blend with methyl sulfate to give the molecule its positive charge. That charge is what lets the ingredient bind to dirt while remaining gentle on skin and hair. First explored in the late 1990s as a milder alternative to harsher surfactants, it quickly found favor with formulators who wanted effective cleansing without excessive stripping.
Today the ingredient is made in controlled, water-free reactors that allow precise temperature and pH adjustments. The final material is purified, dried and milled into a fine, off-white powder that dissolves easily in water or alcohol during product manufacturing.
You will spot Myristoyl Ethyltrimonium Methosulfate in shampoos, rinse-off conditioners, co-wash creams, facial cleansers, micellar waters, cleansing balms and even some lightweight leave-in sprays designed to refresh hair between washes.
Myristoyl Ethyltrimonium Methosulfate’s Cosmetic Benefits/Uses
In formulations Myristoyl Ethyltrimonium Methosulfate plays one key role: cleansing. It lifts away excess oil, product buildup and environmental grime while its fatty acid tail cushions the surfactant action, helping the skin or hair surface stay soft and comfortable after rinsing.
Who Can Use Myristoyl Ethyltrimonium Methosulfate
This mild cleanser works well for most skin and hair types. Its fatty acid backbone softens the surfactant action so it is generally gentle enough for dry or sensitive skin, yet still effective for combination and oily types that need thorough cleansing. People with very reactive or allergy-prone skin should still check the full ingredient list of any product to be sure no other components are problematic, but the quaternary molecule itself is considered low risk for irritation.
The ingredient is usually sourced from coconut or palm oil, making it suitable for vegans and vegetarians. Reputable suppliers document plant origin and synthetic processing with no animal derivatives involved, though consumers who follow strict ethical guidelines may wish to confirm this with individual brands.
No data suggest that topical use of Myristoyl Ethyltrimonium Methosulfate poses a hazard to women who are pregnant or breastfeeding. Formulas that rinse off leave only trace amounts on skin or hair, further reducing systemic exposure. Still, this information is not medical advice and anyone who is pregnant or nursing should run their skincare products past a healthcare professional to be on the safe side.
The molecule does not make skin more prone to sun damage and does not interfere with sunscreen performance, so it is not considered photosensitizing. It is also safe for color-treated hair and does not strip dye molecules more than a typical gentle shampoo would.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical Myristoyl Ethyltrimonium Methosulfate vary from person to person. The points below outline potential issues that could occur, though they are uncommon when the ingredient is used correctly in a finished cosmetic product.
- Mild skin or scalp irritation
- Eye stinging if the product accidentally gets into the eyes
- Allergic contact dermatitis in individuals sensitive to quaternary ammonium compounds
- Excessive dryness if used in very high concentrations or combined with other strong surfactants
- Product buildup that weighs down fine hair when present in rich leave-in formulas
If you experience any of the above effects stop using the product and consult a medical professional if symptoms persist.
Comedogenic Rating
Rating: 1 out of 5. Myristoyl Ethyltrimonium Methosulfate is a cationic cleanser that is highly water soluble and typically used in rinse-off products, so it does not linger long enough on skin to block pores. Its fatty acid tail is relatively lightweight compared with the heavier plant oils often linked to breakouts, which further lowers its clogging potential. While individual formulas can still vary, the ingredient itself is considered low risk for pore congestion. It is generally suitable for people prone to acne or breakouts.
If you are worried about buildup on hairline or back, choose products that are meant to rinse away fully and avoid pairing them with very occlusive leave-on conditioners or styling creams.
Summary
Myristoyl Ethyltrimonium Methosulfate is mainly valued for one thing: gentle yet effective cleansing. Thanks to its positively charged head the molecule grabs onto negatively charged dirt, oil and product residue, while the myristic fatty tail softens the interaction so skin and hair are not left feeling stripped.
You will see it now and then in shampoos, co-wash creams, micellar waters and a few lightweight leave-in sprays, but it is still a niche choice compared with big-name surfactants like sodium laureth sulfate or coco-betaine. Brands that focus on mildness and plant-derived ingredients are the ones most likely to use it.
Current safety data show low irritation, no evidence of systemic toxicity and minimal risk of pore clogging, which makes it a comfortable option for most users. As with any new cosmetic it is wise to patch test a product that contains this ingredient before committing to full-face or full-scalp use, especially if you have very sensitive or allergy-prone skin.