Ingredient review
CI 73900
INCI: CI 73900
CI 73900 is a widely used, safe red pigment that gives makeup its color without causing irritation or clogging pores.
In plain English
CI 73900 is a red pigment, specifically a type of iron oxide, that is added to makeup to create color. It's the same kind of pigment that gives natural clay its red hue, but made in a lab for purity and consistency. In your foundation or blush, it provides a stable, non-irritating red shade that won't fade or change color over time.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is relatively strong for its common cosmetic role.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- strong
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
CI 73900 is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging CI 73900.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
strongThere is a stronger practical or research basis for the ingredient role described here.
What it is
CI 73900 is a synthetic red iron oxide pigment, also known as Pigment Red 101. It is an inorganic compound that provides a stable, opaque red color in cosmetics.
How it works
As a pigment, CI 73900 sits on the surface of the skin or mixes into a product's base to impart a red color. It does not react with skin or absorb into it; it simply reflects and absorbs light to create the visible shade. Its small particle size allows for even distribution and blendability.
Pros
Safe for sensitive skin
CI 73900 is non-irritating and non-comedogenic, making it suitable for even the most reactive skin types.
Color stability
Unlike some natural pigments, this synthetic iron oxide resists fading from UV light and air, so your makeup stays true to shade.
Cons and cautions
Potential for staining
If not properly formulated or removed, the pigment can temporarily stain light-colored fabrics or skin, especially in high-concentration products.
Synthetic origin
Some consumers prefer naturally derived colorants, even though synthetic iron oxides are rigorously purified and tested for safety.
Best for
- Anyone looking for a reliable red pigment in makeup
- People with sensitive skin who need non-irritating colorants
Use caution if
- Those who strictly avoid all synthetic ingredients (though iron oxides are generally considered safe)
Usage tips
Safety summary
CI 73900 is considered safe for use in cosmetics. It is non-toxic, non-irritating, and non-sensitizing. Regulatory bodies worldwide have approved it with no known safety concerns at typical usage levels.
Research notes
Iron oxides, including CI 73900, have been extensively studied and are generally recognized as safe (GRAS) by the FDA. No significant adverse effects have been reported in cosmetic applications.
Common label clues
- Typical concentration
- 0.1% to 5% depending on desired shade intensity
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (Annex IV). No concentration restrictions for external use.
- Common uses
- Foundations, Blushes, Lipsticks, Eyeshadows, Tinted moisturizers
- Environmental note
- Synthetic iron oxides are produced in controlled environments, reducing the environmental impact compared to mining natural pigments. They are not biodegradable but are considered low-risk for aquatic ecosystems at typical cosmetic usage levels.
Good to know
- CI 73900 is part of the iron oxide family, which includes yellow (CI 77492) and black (CI 77499) pigments used to create a wide range of skin tones.
- It is approved for use in cosmetics by the FDA and the EU Cosmetics Regulation.
Common questions
What is CI 73900 in beauty products?
CI 73900 is a red pigment, specifically a type of iron oxide, that is added to makeup to create color. It's the same kind of pigment that gives natural clay its red hue, but made in a lab for purity and consistency. In your foundation or blush, it provides a stable, non-irritating red shade that won't fade or change color over time.
What does CI 73900 do in a beauty product?
As a pigment, CI 73900 sits on the surface of the skin or mixes into a product's base to impart a red color. It does not react with skin or absorb into it; it simply reflects and absorbs light to create the visible shade. Its small particle size allows for even distribution and blendability.
Is CI 73900 safe for most people?
CI 73900 is considered safe for use in cosmetics. It is non-toxic, non-irritating, and non-sensitizing. Regulatory bodies worldwide have approved it with no known safety concerns at typical usage levels.
Who should be careful with CI 73900?
Those who strictly avoid all synthetic ingredients (though iron oxides are generally considered safe)
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.