What Is Bis-Lauryldimoniumhydroxyethyl Bromide (Peg-220/Smdi Copolymer)?
Bis-Lauryldimoniumhydroxyethyl Bromide (PEG-220/SMDI Copolymer) is a man-made polymer that belongs to the quaternary ammonium family. It is created by linking together three key building blocks: PEG-220, saturated methylene diphenyldiisocyanate, and dodecyl(2-hydroxyethyl)dimethylammonium bromide. When these components react, they form a large, stable molecule that carries a positive charge, giving it useful styling and thickening properties in water-based formulas.
The ingredient has no direct plant or animal source; it is produced in a controlled lab setting. Chemists introduced it in the late 1990s as brands looked for reliable alternatives to older thickeners that sometimes separated or felt sticky on the skin. The production process involves step-wise polymerization, followed by neutralization with a bromide salt to secure the final quaternary structure and ensure good shelf life.
You will most often find this copolymer in hair conditioners, styling creams, masks, shower gels, body lotions, facial moisturizers, and certain rinse-off treatments that need a smooth, cushiony texture. Its ability to stabilize a formula helps prevent watery layers from forming and keeps the product feeling pleasant during use.
Bis-Lauryldimoniumhydroxyethyl Bromide (Peg-220/Smdi Copolymer)’s Cosmetic Benefits/Uses
This ingredient plays one main role in cosmetics, and that single role offers several practical payoffs for both formulators and users.
Viscosity controlling: By thickening water-based mixtures, it gives creams and gels a rich, even consistency that spreads easily without dripping. A steady texture means active ingredients stay suspended, so every pump or scoop delivers the same level of performance. It also boosts the cushioning feel on hair or skin, helping products glide on smoothly and rinse off without leaving a heavy film.
Who Can Use Bis-Lauryldimoniumhydroxyethyl Bromide (Peg-220/Smdi Copolymer)
This copolymer is considered gentle enough for most skin types. Normal, dry and oily skin typically tolerate it because the molecule is too large to penetrate deeply and does not disrupt the skin barrier. Sensitive or easily irritated skin can also use it in low to moderate concentrations but may notice mild redness if a formula contains additional fragrances or harsh surfactants.
The ingredient is synthetic and contains no animal derivatives so it is suitable for vegans and vegetarians.
No specific data link Bis-Lauryldimoniumhydroxyethyl Bromide to risks during pregnancy or while breastfeeding. Because absorption through intact skin is negligible it is generally viewed as low concern. This is not medical advice and anyone who is pregnant or nursing should show the full product list to a healthcare professional to confirm safety.
The copolymer does not increase photosensitivity. Standard daily sun protection habits remain recommended for overall skin health but no extra precautions are needed solely because of this ingredient.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical Bis-Lauryldimoniumhydroxyethyl Bromide (Peg-220/Smdi Copolymer) can vary from person to person. The points below describe potential issues but most users will not experience them when the ingredient is used correctly in a finished product.
- Mild skin irritation such as redness or itching, more likely on very sensitive skin
- Eye irritation if the product accidentally gets into the eyes
- Contact allergy marked by small bumps or a rash, considered rare
- Product buildup on hair leading to a weighed-down feel when used in high concentrations without thorough rinsing
If any of these effects occur discontinue use and consult a healthcare professional if symptoms persist or worsen.
Comedogenic Rating
Rating: 0 / 5
Bis-Lauryldimoniumhydroxyethyl Bromide (PEG-220/SMDI Copolymer) is a large, water-dispersible polymer that stays on the skin surface then rinses away easily. It is not oily, does not clog pores and carries a positive charge that helps it bind to hair and skin lightly without forming a greasy film. For these reasons formulators consider it non-comedogenic.
Suitable for acne-prone or breakout-prone skin.
No data suggest it interferes with common acne treatments or alters sebum flow, and it is often paired with clarifying ingredients in rinse-off and leave-on products.
Summary
Bis-Lauryldimoniumhydroxyethyl Bromide (PEG-220/SMDI Copolymer) is used mainly to control viscosity, giving creams gels and conditioners a smooth plush feel while keeping the formula stable from the first squeeze to the last. Its cationic nature lets it coat hair and skin lightly which boosts slip and ease of rinse-off without heaviness.
The ingredient sits in a niche category of modern thickeners. It is not as famous as carbomers or xanthan gum yet brands that need a richer sensorial payoff without stickiness value it highly.
Safety reports show a low irritation profile, minimal absorption and no comedogenic activity, making it a low-risk choice for most users. As with any new cosmetic product a quick patch test is still smart practice to rule out individual sensitivities.