What Is Peg-5 Oleammonium Methosulfate?
Peg-5 Oleammonium Methosulfate is a synthetic ingredient created by joining fatty acids from olive or other vegetable oils with small units of ethylene oxide and then quaternizing the blend with a mild sulfate salt. Chemically it sits in the family of cationic surfactants, meaning it carries a positive charge that is attracted to the negatively charged surface of hair. The “5” in its name signals an average of five ethylene oxide units linked to each fatty chain, which gives the molecule a good balance between oil loving and water loving parts.
Interest in this type of conditioning agent began in the late 1980s when formulators looked for alternatives to heavier quats that could smooth hair without weighing it down. By tweaking the chain length and the number of ethylene oxide units, researchers produced a lighter yet still effective conditioner that rinses clean. Today Peg-5 Oleammonium Methosulfate is manufactured in large reactors where controlled amounts of ethylene oxide are added to oleyl amine, followed by neutralization with methyl sulfate. The final liquid is purified, checked for residual impurities, and delivered to cosmetic labs as a clear to pale yellow viscous fluid.
You will most often see this ingredient in rinse-off and leave-in hair conditioners but it can also appear in 2-in-1 shampoos, hair masks, detangling sprays, and color-protect formulas. Its mildness lets brands include it in products aimed at sensitive scalps or fine hair that cannot tolerate heavy build-up.
Peg-5 Oleammonium Methosulfate’s Cosmetic Benefits/Uses
Peg-5 Oleammonium Methosulfate brings one primary benefit to hair care products.
Hair conditioning: The positive charge in the molecule is attracted to the negatively charged spots along damaged hair strands, allowing it to cling even after rinsing. This thin, even layer smooths the cuticle, reduces static, improves comb-through, and leaves hair feeling softer and looking shinier without a greasy finish.
Who Can Use Peg-5 Oleammonium Methosulfate
This light conditioner works well for all hair types including fine, thick, curly, color treated and chemically relaxed strands. It is also gentle enough for most scalp skin types from oily to dry and sensitive because it does not contain harsh detergents or heavy oils that can clog follicles or leave residue.
The ingredient is synthesized from plant derived fatty acids and petrochemical ethylene oxide, then reacted with a mild sulfate salt. No animal sources or byproducts are used so products featuring Peg-5 Oleammonium Methosulfate are generally suitable for both vegans and vegetarians. As always, check the full product label to be sure other animal derived ingredients are not included.
Based on current safety data, topical use during pregnancy or while breastfeeding is not expected to pose a risk. That said this information is not medical advice. Anyone who is pregnant or nursing should review personal care products with their healthcare provider to be on the safe side.
Peg-5 Oleammonium Methosulfate does not make skin or hair more sensitive to sunlight and can be used alongside daytime styling products without extra sun precautions.
Potential Side Effects/Adverse Reactions
Side effects and reactions to the topical application of Peg-5 Oleammonium Methosulfate can vary from person to person. The points below list potential but uncommon issues. When the ingredient is used correctly in a well formulated product most people will not experience any problems.
- Mild scalp or skin irritation especially on very sensitive or broken skin
- Allergic contact dermatitis in individuals allergic to quaternary ammonium compounds
- Eye stinging or redness if the product accidentally gets into the eyes
- Product buildup that can leave hair limp or dull when very high amounts are used without adequate cleansing
- Interaction with strong anionic surfactants which can cause cloudiness or reduced performance in DIY mixes
If any burning itching swelling or other discomfort occurs stop using the product and consult a healthcare professional
Comedogenic Rating
Rating: 1 / 5
Peg-5 Oleammonium Methosulfate is built around a long olive-derived fatty chain, yet that chain is heavily modified with ethylene oxide units and carries a permanent positive charge. These changes make the molecule highly water dispersible so it does not linger on skin pores the way untreated oils can. In rinse-off hair products any residue that touches facial skin is quickly removed with water which keeps the risk of clogged pores low.
Because of its low tendency to block pores this ingredient is generally considered suitable for people who are prone to acne or breakouts.
Comedogenicity may rise slightly if the ingredient sits on skin for long periods in rich leave-in treatments but even then the risk remains minimal compared with heavier quaternary conditioners.
Summary
Peg-5 Oleammonium Methosulfate is a light cationic surfactant used almost exclusively for hair conditioning. Its positively charged head seeks out the negatively charged damaged spots along each strand where it forms a thin film that smooths the cuticle, cuts static and improves softness and shine without a greasy feel.
While not as widely known as behentrimonium chloride or cetrimonium bromide it has carved out a steady niche in modern conditioners aimed at fine hair and sensitive scalps thanks to its mildness and clean rinsing profile.
Current safety data show very low irritation potential when used at normal cosmetic levels and no evidence of long-term health concerns. As with any new personal care product it is wise to perform a quick patch test before full use especially if you have sensitive skin or a history of allergies.