Black iron oxide (CI 77499): properties, uses, INCI functions, safety, alternatives

Black iron oxide – triiron tetraoxide (predominantly Fe₃O₄, magnetite)

Synonyms: black iron oxide, Pigment Black 11, E172 (food colorant; purity requirements are often used as a reference for cosmetic grades as well)
INCI / functions: colorant

Definition
Black iron oxide is an inorganic pigment based on iron oxides, used mainly as a colorant in cosmetic formulations (make-up, colored products for face/eyes/lips, and sometimes hair cosmetics). From a compositional standpoint, it is primarily associated with ferrous–ferric oxide (triiron tetraoxide, Fe₃O₄). In regulatory and database contexts, the “CI 77499” entry may be linked to multiple CAS/EC identifiers associated with iron oxides/related forms, depending on the registered substance definition and the commercial grade. In formulation, its technical value comes from stability (light/heat), inertness, and the ability to modulate depth and “blackness” in pigment blends.

Main uses 

• Food: as E172 (iron oxides and hydroxides), where applicable by category.

• Cosmetics: colorant (ref. Annex IV, dedicated entry), especially in make-up and decorative products.

Restricted cosmetic ingredient as IV/137  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

    Iron Oxide Black. Wording of conditions of use and warnings:  Purity criteria as set out in Commission Directive 95/45/EC (E172)

INCI Functions

Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

Black iron oxide is used in cosmetic products such as eyeliners, mascaras, eyeshadows, and foundations due to its intense black color and high opacity. It provides long-lasting color.

• Medicine: not a standard “ingredient” use; any use is dossier-specific.

• Pharmaceutical: potential technical use as a colorant pigment/excipient in specific cases (specification- and authorization-dependent).

• Industrial use: pigment for coloration and technical applications (coatings, plastics, etc.).

Identification data and specifications

Key constituents

Functional role and expected performance

Use guidelines (indicative)

Formulation compatibility
Black iron oxide is generally compatible with most cosmetic systems, but success is dominated by dispersion: pigment wetting, dispersant selection (if used), and shear management. In O/W emulsions and cream systems, incorporation is typically via pre-dispersion in the oil phase or dedicated carriers; in anhydrous systems (sticks, lipsticks), proper deagglomeration is critical to prevent speckling and non-uniformity.

In systems with electrolytes or specific polymers, the pigment can affect rheology (increased apparent viscosity, yield stress) and suspension stability. In very fluid “clean look” products, sedimentation tendency may increase and is addressed with structurants, rheology modifiers, and particle-size distribution optimization. If the grade is supplied in nano form, EU compliance and nanomaterial labeling obligations apply (case-by-case, based on regulatory definition and supplier documentation).

Quality, grades and specifications

Safety, regulatory and environment
Black iron oxide is a permitted cosmetic colorant in the European Union via inclusion in Annex IV (dedicated entry). Operationally, safety is assessed on the finished product (use scenario, application area, population, impurity profile). For inorganic pigments, key technical points are: control of impurities (trace metals), management of dust in production (respiratory protection for operators), and confirmation of documentary compliance for the selected grade. Environmentally, as a mineral pigment, impacts relate mainly to dust and industrial effluent handling; use in finished products typically results in low direct emissions, while responsible management is primarily a supply-chain and process-wastewater topic under local regulations.

Formulation troubleshooting

Conclusion
Black iron oxide is an inorganic pigment (black iron oxide, mainly Fe₃O₄) used as a cosmetic colorant due to stability and reliable performance. Final quality depends primarily on the grade (purity, particle size) and dispersion (wetting, deagglomeration, rheology), as well as control of impurities and regulatory compliance (Annex IV, entry 137).

Studies

Ultraviolet rays from the sun cause skin aging and smartphones emit high-energy visible light from which you should protect yourself. Iron oxides (yellow, red and black) in sunscreens have the property of effectively blocking high-energy visible light especially when combined with zinc oxide (1).

CI 77492 is generally considered safe for use in consumer products when handled according to proper safety procedures. It is important to avoid inhalation of the powder and minimize direct contact with skin and eyes (1).

Ultraviolet rays from the sun cause skin aging and smartphones emit high-energy visible light from which you should protect yourself. Iron oxides (yellow, red and black) in sunscreens have the property of effectively blocking high-energy visible light especially when combined with zinc oxide (1).

As regards food safety, being an additive also added in fruits and vegetables, for these foods a maximum permissible level of 6 milligrams per kilo body and the formula "enough" in 48 categories of food  (Regulation (EC) No 1333/2008). Within these categories of foods, iron oxides and hydroxides are allowed in liquid food supplements, food supplements in syrup, in solid form, including capsules and tablets and similar forms, excluding chewable. However, EFSA recommends further scientific analysis (3).

Makeup cosmetics such as eye cosmetics that contain a high percentage of black iron oxide should be removed before MRI examination.(4)

Iron oxide CI 77499 studies

• Molecular Formula : Fe₂O₃    Fe₂H₆O₃
• Molecular Weight : 159,69 g/mol
• CAS : 1309-37-1    1332-37-2
• UNII 
• EC Number: 215-168-2
• DSSTox Substance ID: 
• MDL number  
• MFCD00011008
• PubChem Substance ID 329753614
• InChI=1S/2Fe.3H2O/h;;3*1H2
• InChl Key      YOBAEOGBNPPUQV-UHFFFAOYSA-N
• SMILES    O.O.O.[Fe].[Fe]
• IUPAC iron;trihydrate
• ChEBI    

Synonyms:

• Iron Oxide Black
• Pigment Black 11
• Black Iron Oxide
• CI77499
• E172 (i)
• Ferric oxide

References____________________________________________________________________

(1) Aquilina, G., Azimonti, G., Bampidis, V., de Lourdes Bastos, M., Bories, G., Chesson, A., ... & Wester, P. (2016). Safety and efficacy of iron compounds (E1) as feed additives for all species: ferric oxide based on a dossier submitted by Poortershaven Industriële Mineralen BV. EFSA JOURNAL, 14(6), 1-26.

Abstract. The additive under assessment, ferric oxide, contains between 57% and 69% iron (Fe). The EFSA FEEDAP Panel could not conclude on the safety of ferric oxide for the target animals owing to that (i) the application of ferric oxide red is for all animal species, (ii) lifetime administration to animals is not excluded and (iii) a sufficient biological and toxicological database was not available. Regarding (i) the very low absorption of iron from the ferric oxide by target animals and (ii) the homoeostatic regulation of iron metabolism in animals, any influence of feeding the ferric oxide on the iron content of edible tissues and products is not expected. The use of ferric oxide in animal nutrition is unlikely to result in a direct exposure of the consumer to this oxide. Consequently, the supplementation of feed for food-producing animals with ferric oxide would likely not constitute a risk to consumers. Ferric oxide is an irritant to skin and eyes by mechanical action. Owing to the nickel content in the additive, the ferric oxide

(2) Bernstein EF, Sarkas HW, Boland P. Iron oxides in novel skin care formulations attenuate blue light for enhanced protection against skin damage. J Cosmet Dermatol. 2021 Feb;20(2):532-537. doi: 10.1111/jocd.13803. 

(3) EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS)
First published: 08 December 2015 https://doi.org/10.2903/j.efsa.2015.4317

(4) Hoshi Y, Tateishi T, Yabe K, Kimura T, Sone O, Nakanishi S, Saotome K. Fundamental Study on Artifacts and Displacement Force of Cosmetics Such as Eye Makeup in MRI Examinations. Nihon Hoshasen Gijutsu Gakkai Zasshi. 2024;81(2). Japanese. doi: 10.6009/jjrt.25-1466. PMID: 39631939.

Safety

CI 77499 is a black colored pigment, for which all the warnings concerning iron oxide in general are valid. In this regard, there is a large documentation of EFSA (1).

Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles as drug transporters can add further functionalities, such as guidance or heating by external magnetic fields (Magnetic Drug Targeting or Magnetic Hyperthermia), and imaging-controlled therapy (Magnetic Resonance Imaging) (2).

The objective of this work is to address this problem from the theoretical side by performing detailed simulations to investigate the effect of incorporation of magnetic nanoparticles in clusters on the amount of heat generated as a function of the particle size, cluster size and particles magnetic properties (3).

Polyethyleneimine-coated Iron Oxide Nanoparticles as a Vehicle for the Delivery of Small Interfering RNA to Macrophages In Vitro and In Vivo (4).

Iron Oxide as a Contrast Agent

This study focuses on the function of iron oxide as a contrast agent for cell tracking by magnetic resonance (5).

Iron Oxide as Dietry Supplement

Comparison of the Effects of Iron Oxide, as a New Form of Iron Supplement, and Ferrous Sulfate on the Blood Levels of Iron and Total Iron-Binding Globulin (6).

References_____________________________________________________________

(1) EFSA JOURNAL Safety and efficacy of iron oxide black, red and yellow for all animal species
Volume 14, Issue 6, June 2016, EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)
Version of Record online : 6 JUN 2016, DOI: 10.2903/j.efsa.2016.4482

(2) Janko C, Ratschker T, Nguyen K, Zschiesche L, Tietze R, Lyer S, Alexiou C. Functionalized Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as Platform for the Targeted Multimodal Tumor Therapy.  Front Oncol. 2019 Feb 13;9:59. doi: 10.3389/fonc.2019.00059. eCollection 2019

(3) Lattuada M. Effect of Clustering on the Heat Generated by Superparamagnetic Iron Oxide Nanoparticles. Chimia (Aarau). 2019 Feb 27;73(1):39-42. doi: 10.2533/chimia.2019.39.

(4) Jia N, Wu H, Duan J, Wei C, Wang K, Zhang Y, Mao X. Polyethyleneimine-coated Iron Oxide Nanoparticles as a Vehicle for the Delivery of Small Interfering RNA to Macrophages In Vitro and In Vivo. J Vis Exp. 2019 Feb 5;(144). doi: 10.3791/58660.

(5) Korchinski DJ, Taha M, Yang R, Nathoo N, Dunn JF. Iron Oxide as an MRI Contrast Agent for Cell Tracking.  Magn Reson Insights. 2015 Oct 6;8(Suppl 1):15-29. doi: 10.4137/MRI.S23557. eCollection 2015. Review.

(6) Kheiri R, Koohi MK, Sadeghi-Hashjin G, Nouri H, Khezli N, Hassan MA, Hoomani F, Shams G, Rasouli A, Motaghinejad M. Comparison of the Effects of Iron Oxide, as a New Form of Iron Supplement, and Ferrous Sulfate on the Blood Levels of Iron and Total Iron-Binding Globulin in the Rabbit.  Iran J Med Sci. 2017 Jan;42(1):79-84.