Ingredient review
Red 40
INCI: CI 16035
A widely used synthetic red dye that adds color to cosmetics but offers no skincare benefits.
In plain English
CI 16035, also known as Red 40, is a man-made colorant that gives cosmetics a red or pink hue. It is derived from petroleum and is approved for use in many countries. In skincare, it is purely aesthetic—it does not treat or improve the skin. Some people may experience mild irritation or allergic reactions, but for most, it is safe in the small amounts used in cosmetics.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
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
Useful, but context matters
Red 40 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 40.
- 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
A synthetic azo dye produced from petroleum byproducts, commonly used to color food, drugs, and cosmetics.
How it works
It absorbs and reflects specific wavelengths of light to produce a red color. In cosmetics, it is mixed into formulas to achieve desired shades without affecting the product's function or skin feel.
Pros
Vibrant color payoff
Provides a bright, consistent red shade that doesn't fade easily in typical cosmetic formulations.
Cost-effective
Synthetic production makes it inexpensive compared to natural red pigments like carmine or iron oxides.
Cons and cautions
No skincare benefit
It is purely decorative and does not moisturize, protect, or improve skin health.
Potential irritant for sensitive skin
A small percentage of people may experience redness, itching, or contact dermatitis, especially with prolonged use.
Best for
- Anyone looking for a reliable red color in their cosmetics
- People without known sensitivities to synthetic dyes
Use caution if
- Those with known allergies or sensitivities to azo dyes
- Individuals seeking 100% natural or plant-based colorants
Usage tips
Safety summary
Generally recognized as safe for cosmetic use at typical concentrations. Rare cases of allergic contact dermatitis have been reported. Regulatory bodies consider it safe when used according to guidelines.
Research notes
Studies confirm low acute toxicity and low skin irritation potential in most individuals. Some research links oral ingestion of Red 40 to behavioral issues in children, but topical cosmetic use is not associated with these effects.
Common label clues
- Typical concentration
- Typically less than 1% in leave-on products; higher in rinse-off products
- Regulatory status
- Approved for use in cosmetics by the U.S. FDA and the European Commission (listed as CI 16035). Subject to purity and labeling requirements.
- Common uses
- Lipsticks, Blushes, Eyeshadows, Foundations, Soaps, Bath products
- Environmental note
- As a synthetic dye, it is derived from non-renewable petroleum sources and may not biodegrade readily in the environment.
Good to know
- Red 40 is one of the most common colorants in cosmetics and is approved by the FDA for use in drugs and cosmetics.
- It is sometimes listed as 'FD&C Red No. 40' on U.S. labels.
Common questions
What is Red 40 in beauty products?
CI 16035, also known as Red 40, is a man-made colorant that gives cosmetics a red or pink hue. It is derived from petroleum and is approved for use in many countries. In skincare, it is purely aesthetic—it does not treat or improve the skin. Some people may experience mild irritation or allergic reactions, but for most, it is safe in the small amounts used in cosmetics.
What does Red 40 do in a beauty product?
It absorbs and reflects specific wavelengths of light to produce a red color. In cosmetics, it is mixed into formulas to achieve desired shades without affecting the product's function or skin feel.
Is Red 40 safe for most people?
Generally recognized as safe for cosmetic use at typical concentrations. Rare cases of allergic contact dermatitis have been reported. Regulatory bodies consider it safe when used according to guidelines.
Who should be careful with Red 40?
Those with known allergies or sensitivities to azo dyes Individuals seeking 100% natural or plant-based 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.