INCI: CI 77510
Mineral blue pigment – ferric ferrocyanide (Prussian Blue). Gives deep dark blue in eyeshadows, eyeliners, mascaras. Stable, inert. The cyanide ion is tightly bound to iron and does not release – the pigment is safe. Banned for lips in the US (FDA).
Topical application
BLimited evidence. One RCT or several controlled studies with limitations.
Functional mineral pigment. Banned in the US for lips (FDA 21 CFR 73.1298). No cosmetic skin activity.
Ferric Ferrocyanide (CI 77510, Prussian Blue) is a synthetic deep-dark-blue mineral pigment. Chemical formula Fe4[Fe(CN)6]3. Discovered in 1704, one of the oldest synthetic pigments. Used not only in cosmetics but as a medical antidote to radioactive cesium and thallium poisoning. Where applied. Decorative cosmetics: eyeshadows, eyeliners, mascaras, cream correctors. Concentration 1-20%. In Spain – in niche professional cosmetics Mac, Make Up For Ever, Sensilis. Less common in pharmacy decorative cosmetics due to the cool tone. Mechanism. Mineral pigment, does not react with skin, does not penetrate the epidermis. Colors the surface via light reflection. Stable. The cyanide ion in the molecule is firmly bound to iron and is not released – the pigment is safe and non-toxic. Evidence base. Functional pigment. No skin therapeutic efficacy. In medicine known as Radiogardase – an oral antidote for radiocesium poisoning (Chernobyl, Fukushima) and thallium. Safety. CIR confirmed safety. SCCS imposed no restrictions. Allergic reactions extremely rare. Non-sensitizing. Zero systemic absorption through intact skin. Cyanide naming controversy. The word "cyanide" in the composition scares consumers, but chemically the cyanide ion is bound to iron so firmly that it does not dissociate in water or stomach acid. This same stability allows oral Prussian Blue as an antidote. FDA restriction. Banned in the US in lip and mucosal products (like most blue pigments, including ultramarines). In the EU and Spain – allowed everywhere except mucosa. Pregnancy and lactation – safe. Acceptable at any stage. Suitable for. Universal in decorative cosmetics. Sensitive eyelid skin – not problematic.
Irritation potential
LowAllergen risk
LowPregnancy
SafeThe Evigrade extension adds an evidence panel to Wildberries, Goldapple, Letu, iHerb, Sephora and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
CI 77510 (Ferric Ferrocyanide) is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
CI 77510 (Ferric Ferrocyanide) suits: normal, dry, combination, oily, sensitive.
Mineral blue pigment – ferric ferrocyanide (Prussian Blue).
The INCI name is CI 77510. It may also appear as: Ferric Ferrocyanide, Prussian Blue, Iron Blue.
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Suitable for