CI 77510 (Ferric Ferrocyanide)
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).
Supporting ingredient
It gives a product its texture, stability or shelf life. It has no claimed effect on the skin, so an efficacy tier does not apply. What is known about its safety is below
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
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.
Frequently asked questions
Is CI 77510 (Ferric Ferrocyanide) safe during pregnancy?
CI 77510 (Ferric Ferrocyanide) is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is CI 77510 (Ferric Ferrocyanide) for?
CI 77510 (Ferric Ferrocyanide) suits: normal, dry, combination, oily, sensitive.
What is CI 77510 (Ferric Ferrocyanide) and what does it do in cosmetics?
Mineral blue pigment – ferric ferrocyanide (Prussian Blue).
What's the INCI name for CI 77510 (Ferric Ferrocyanide)?
The INCI name is CI 77510. It may also appear as: Ferric Ferrocyanide, Prussian Blue, Iron Blue.
See CI 77510 (Ferric Ferrocyanide) in a product composition right on the store page
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