Ci 77400

If you've ever seen a product shimmer with a warm, metallic glow that looks genuinely metallic—not just sparkly—you might have encountered CI 77400, also known as Copper Powder or Bronze Powder. Chemically, this is a true inorganic colorant, meaning it's not a synthetic dye but rather a finely ground metal. It consists primarily of elemental copper or an alloy of copper and zinc, sometimes with trace amounts of aluminum or tin to tweak the final hue. Because it's literally metal, it doesn't degrade or fade like organic pigments can, and it offers a distinctive reflective quality that's hard to replicate with mica or synthetic glitter. In its pure form, copper is a reddish-brown metal, but when alloyed with zinc, it shifts toward a golden-bronze tone—hence the dual naming in cosmetics.

In cosmetic formulations, CI 77400 works as a colorant and cosmetic colorant, meaning its sole job is to impart color and visual effect. Unlike some pigments that work by absorbing certain wavelengths of light, this one primarily reflects light due to its metallic nature, creating a high-shine, almost mirror-like finish. Formulators use it at low concentrations—typically between 0.1% and 1%—because a little goes a long way, and higher amounts can feel gritty or cause the product to separate. It's most commonly found in pressed powders, eyeshadows, lipsticks, and highlighters where a true metallic sheen is desired. Because it's a metal powder, it must be carefully dispersed in a base to avoid clumping, and it's often coated with a thin layer of silica or a fatty acid to improve spreadability and skin adhesion.

The main benefit of CI 77400 is its intense, authentic metallic luster that no synthetic pigment can fully mimic. It gives products a warm, antique-gold or coppery glow that appears three-dimensional on the skin, catching light from every angle. This is particularly valuable in "liquid metal" or "foiled" eye shadows and cream highlighters where you want a wet-looking, high-impact finish. The evidence for its visual effect is purely empirical—it's a physical property of the metal itself—so there's no clinical study needed to prove its shine. However, it does have a practical advantage over some organic pigments: it's extremely color-stable, meaning it won't shift or fade over time, even in products stored for years. That said, its benefits are purely aesthetic; it offers no skincare or treatment properties.

This ingredient is best suited for normal to oily skin types because the metallic particles can sometimes emphasize texture or dry patches on dry or mature skin. If you have sensitive skin, there's a potential concern: copper is a known allergen for some people, and direct contact with the metal can cause irritation or even a mild allergic reaction in those with copper sensitivity. It's also not recommended for use around the eyes if you wear contact lenses, as the fine metal particles could migrate and cause discomfort. On the positive side, CI 77400 is generally compatible with most other ingredients, including silicones, oils, and waxes, though it should not be used in water-based formulas without proper stabilization because it can oxidize and darken over time. Products containing it are best kept in airtight, opaque packaging to prevent tarnishing.

If you're scanning an ingredient list, CI 77400 will appear under its INCI name, but you might also see it listed as "Copper Powder" or "Bronze Powder." A fun fact: because it's actual metal, it is electrically conductive—meaning if you have a very dry powder product, you might notice a faint metallic smell, though this is harmless. In the EU, CI 77400 is strictly regulated as a colorant and must meet purity standards to ensure no toxic impurities like lead or arsenic are present. Interestingly, this same ingredient is used in industrial applications like conductive inks and paints, so the cosmetic-grade version is highly refined and processed to be safe for skin. When you see it in a product, expect a high-shine, almost liquid-looking finish that feels smooth but can have a slight "grip" when applied—unlike mica, which feels silky, copper powder has a denser, more substantial texture.