What Is Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer?
Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer is a film-forming polymer created by reacting guanidine carbonate with two well-known building blocks used in modern polyurethane chemistry: hexamethylene diisocyanate and methylene diphenyl diisocyanate. When these pieces are combined under controlled heat and pressure they link into long chains that are then trimmed into a steady cross-linked network. The end result is a stable powder or viscous liquid that dissolves or disperses in water or alcohol-based systems.
The core materials come from widely available industrial sources. Guanidine carbonate is produced by reacting guanidine with carbonic acid while the diisocyanates are made from petroleum-derived anilines. Chemists began blending these materials in the late 1990s to answer the cosmetic market’s need for flexible, lightweight films that could hold active ingredients on the skin without a heavy feel. Over time the blend proved useful in makeup, sunscreens and specialty skincare so suppliers scaled up production using closed reactors that capture excess isocyanate fumes for safety.
Today you will spot Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer in sheet masks, color-stay foundations, long-wear eyeliners, peel-off treatments, setting sprays, anti-aging serums and water-resistant sunscreens. It is prized for forming an invisible veil that helps formulas stay put, improves spreadability and leaves a smooth touch.
Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer’s Cosmetic Benefits/Uses
This ingredient serves one main purpose in topical products.
- Film forming: It creates a thin flexible layer on the skin or hair that locks in moisture, boosts wear time of pigments and actives, enhances water resistance in sunscreens and prevents smudging in makeup. The film is breathable so it does not feel tight or flaky yet it provides enough hold to keep the formula working for hours.
Who Can Use Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer
This polymer is considered friendly to most skin types including dry, oily, combination and normal skin because it forms a light breathable film that rarely clogs pores or disrupts the skin barrier. Sensitive skin users generally tolerate it well since it sits on the surface rather than penetrating deeply, though anyone prone to contact allergies should still pay attention to the full ingredient list of the finished product.
The raw materials and manufacturing process involve no animal derived substances, making the ingredient suitable for both vegans and vegetarians. Suppliers typically certify it as synthetic and cruelty free.
Current safety data show no specific hazards for pregnant or breastfeeding women when the ingredient is used topically in cosmetics. Still this is not medical advice and anyone expecting or nursing should review their routine with a physician to be extra safe.
The polymer itself does not cause photosensitivity and will not make skin more prone to sunburn. In fact its film forming ability can improve the staying power of sunscreens applied over it. There are no known interactions with common skincare actives like retinoids or vitamin C.
Potential Side Effects/Adverse Reactions
Side effects from topical use of Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer vary from person to person. The points below list potential reactions that are unlikely for most users when the ingredient is properly formulated and used as directed.
- Mild skin irritation
- Redness or warmth at the application site
- Transient itching or tingling shortly after application
- Rare allergic contact dermatitis in individuals sensitive to isocyanate residues
If any discomfort persists or worsens discontinue use and seek advice from a qualified healthcare professional.
Comedogenic Rating
Rating: 1/5
This polymer sits on top of the skin in a lightweight, breathable layer and has a large molecular size that keeps it from slipping into pores where clogging could occur. It contains no oily carriers or waxy residues that typically raise pore-clogging potential. While trace isocyanate impurities might cause irritation for a small subset of users, they do not increase comedogenicity. Overall it is considered suitable for acne-prone or breakout-prone skin, though individual results can vary.
Summary
Guanidine Carbonate/Hdi Isocyanurate Trimer/Mdi Crosspolymer is mainly valued for its ability to form a clear, flexible film that locks actives in place, boosts water resistance and extends wear time in makeup and sunscreen. It achieves this by creating a cross-linked network over the skin that resists sweat and movement without feeling heavy or sticky.
Although not a household name, the polymer is gaining quiet popularity in long-wear foundations, setting sprays and next-gen sheet masks because formulators appreciate its performance and versatility.
Current research and industry reviews label it as low risk for irritation, non-sensitizing for most users and vegan friendly. As with any new cosmetic ingredient, it is wise to patch test a fresh product before applying it to the entire face to ensure personal compatibility.