Ingredient review
Red 4 (CI 16255)
INCI: CI 16255
A common synthetic red dye that adds color to cosmetics but offers no skincare benefits; generally safe for most people but may cause reactions in sensitive individuals.
In plain English
CI 16255 is a synthetic red dye, also known as Red 4 or Ponceau 4R. It's added to cosmetics like lipstick, blush, and eyeshadow to give them a red or pink color. It doesn't do anything for your skin—it's purely for appearance. While it's considered safe for most people by regulators, a small number of people may experience skin irritation or allergic reactions, especially if they have sensitive skin.
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
Red 4 (CI 16255) 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 Red 4 (CI 16255).
- 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 16255 is a water-soluble synthetic azo dye. It is produced from petroleum and is used to impart a red or pink hue to cosmetic products.
How it works
It works by absorbing and reflecting specific wavelengths of light, which our eyes perceive as the color red. In a cosmetic product, it is simply mixed into the formula to give it color.
Pros
Vibrant color
Provides a bright, consistent red or pink shade that is stable in many cosmetic formulations.
Regulatory approval
Approved for use in cosmetics by major regulatory bodies like the FDA and EU, when used within specified limits.
Cons and cautions
No skincare benefit
This ingredient is purely cosmetic and offers no moisturizing, anti-aging, or other skin benefits.
Potential for irritation
A small percentage of people may experience contact dermatitis or allergic reactions, especially those with sensitive skin or a history of reactions to synthetic dyes.
Best for
- Anyone looking for a vibrant red color in their makeup
- People without known sensitivities to synthetic dyes
Use caution if
- Individuals with known allergies or sensitivities to synthetic dyes or azo dyes
- Those with very sensitive or reactive skin who prefer to avoid synthetic colorants
Usage tips
Safety summary
CI 16255 is generally considered safe for use in cosmetics at regulated concentrations. However, it can cause allergic reactions or irritation in a small subset of individuals, particularly those with sensitive skin or known dye allergies.
Research notes
Research indicates that CI 16255 has low acute toxicity and is not a significant skin sensitizer for the general population. However, case reports of contact dermatitis exist, and some studies suggest potential for allergic reactions in sensitive individuals.
Common label clues
- Typical concentration
- Typically used at very low concentrations, often less than 1%
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU, subject to concentration limits and purity requirements.
- Common uses
- Lipsticks, Blushes, Eyeshadows, Nail polishes, Bath products
- Environmental note
- As a synthetic dye derived from petroleum, its production has a higher environmental footprint compared to natural colorants. It may also contribute to water pollution if not properly treated during manufacturing.
Good to know
- CI 16255 is sometimes listed as Red 4 or Ponceau 4R on labels.
- It is different from Red 40 (CI 16035), which is another common synthetic dye.
Common questions
What is Red 4 (CI 16255) in beauty products?
CI 16255 is a synthetic red dye, also known as Red 4 or Ponceau 4R. It's added to cosmetics like lipstick, blush, and eyeshadow to give them a red or pink color. It doesn't do anything for your skin—it's purely for appearance. While it's considered safe for most people by regulators, a small number of people may experience skin irritation or allergic reactions, especially if they have sensitive skin.
What does Red 4 (CI 16255) do in a beauty product?
It works by absorbing and reflecting specific wavelengths of light, which our eyes perceive as the color red. In a cosmetic product, it is simply mixed into the formula to give it color.
Is Red 4 (CI 16255) safe for most people?
CI 16255 is generally considered safe for use in cosmetics at regulated concentrations. However, it can cause allergic reactions or irritation in a small subset of individuals, particularly those with sensitive skin or known dye allergies.
Who should be careful with Red 4 (CI 16255)?
Individuals with known allergies or sensitivities to synthetic dyes or azo dyes Those with very sensitive or reactive skin who prefer to avoid synthetic colorants
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.