Ingredient review
CI 26100
INCI: CI 26100
CI 26100 is a safe, widely used synthetic red dye for wash-off cosmetics, but offers no skincare benefits and may cause rare allergic reactions in sensitive individuals.
In plain English
CI 26100 is a man-made red colorant that gives a vibrant red hue to products like soap, shampoo, and lipstick. It doesn't do anything for your skin—it's purely for looks. In the U.S., it's approved for use in cosmetics, but it's best for products that rinse off quickly, as it's not meant to stay on your skin for long periods.
Review score
Safety, usefulness, and evidence
Useful in the right context, but not low-maintenance
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Read the cautions before using
CI 26100 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 26100.
- 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
moderateThere is useful support, but formula details and claim strength still matter.
What it is
CI 26100 is a synthetic organic pigment, also known as D&C Red No. 17. It belongs to the monoazo class of dyes and is produced through chemical synthesis. It is used to add red color to cosmetic products.
How it works
As a colorant, CI 26100 works by absorbing and reflecting specific wavelengths of light, creating a red appearance. It is dispersed in the product base (e.g., soap or shampoo) and adheres to the skin or hair temporarily during use, then rinses away.
Pros
Vibrant color
Provides a bright, consistent red shade that is stable in wash-off products like soaps and shampoos.
Regulatory approval
Approved by the U.S. FDA and other global regulators for use in cosmetics, giving consumers confidence in its safety.
Cons and cautions
No skincare benefit
CI 26100 is purely cosmetic—it adds color but does not moisturize, protect, or improve skin health.
Potential for irritation
Though rare, some people may experience allergic reactions or irritation, especially if used in leave-on products.
Best for
- Anyone using wash-off products like soap or shampoo who wants a red color
- People without known sensitivities to synthetic dyes
Use caution if
- Individuals with known allergies or sensitivities to synthetic colorants
- Those seeking skincare benefits from their products
Usage tips
Safety summary
CI 26100 is considered safe for use in wash-off cosmetics at typical concentrations. Rare allergic reactions have been reported, but overall risk is low. It is not recommended for leave-on products due to potential for irritation.
Research notes
Research on CI 26100 is limited, but regulatory bodies like the FDA and EU SCCS have reviewed its safety and approved it for cosmetic use. No significant health risks have been identified at current usage levels.
Common label clues
- Typical concentration
- Typically used at very low concentrations (less than 1%) to achieve desired color.
- Regulatory status
- Approved for use in cosmetics in the U.S. (FDA) and EU (as listed in Annex IV of the Cosmetics Regulation). However, it is restricted to certain product types and concentrations in some regions.
- Common uses
- Soaps, Shampoos, Bath products, Lip products
- Environmental note
- As a synthetic dye, CI 26100 is not biodegradable and may contribute to water pollution if not properly filtered during manufacturing. Some consumers prefer natural colorants for environmental reasons.
Good to know
- CI 26100 is also known as D&C Red No. 17 in the U.S. and is listed on ingredient labels under its Color Index number.
- It is not recommended for use in products intended to stay on the skin for long periods, such as moisturizers or serums.
Common questions
What is CI 26100 in beauty products?
CI 26100 is a man-made red colorant that gives a vibrant red hue to products like soap, shampoo, and lipstick. It doesn't do anything for your skin—it's purely for looks. In the U.S., it's approved for use in cosmetics, but it's best for products that rinse off quickly, as it's not meant to stay on your skin for long periods.
What does CI 26100 do in a beauty product?
As a colorant, CI 26100 works by absorbing and reflecting specific wavelengths of light, creating a red appearance. It is dispersed in the product base (e.g., soap or shampoo) and adheres to the skin or hair temporarily during use, then rinses away.
Is CI 26100 safe for most people?
CI 26100 is considered safe for use in wash-off cosmetics at typical concentrations. Rare allergic reactions have been reported, but overall risk is low. It is not recommended for leave-on products due to potential for irritation.
Who should be careful with CI 26100?
Individuals with known allergies or sensitivities to synthetic colorants Those seeking skincare benefits from their products
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.