Ingredient review
CI 45405
INCI: CI 45405
CI 45405 is a synthetic red dye that adds color to cosmetics, but it has raised safety concerns and is restricted or banned in some countries.
In plain English
CI 45405 is a man-made red pigment used to give lipsticks, blushes, and other makeup their color. It's also known as Acid Red 1. Because it's a synthetic dye, it doesn't do anything for your skin—it's purely for appearance. Some studies have raised concerns about its safety, which is why it's banned in the European Union for cosmetic use, though it may still appear in products sold elsewhere. If you prefer to avoid controversial colorants, you might want to check labels for this ingredient.
Review score
Safety, usefulness, and evidence
Higher-caution ingredient
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Read the cautions before using
CI 45405 can be useful, but watch for some irritation potential.
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 45405.
- 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
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 45405 is a synthetic azo dye that produces a red color. It is part of the Color Index system used to identify pigments and dyes in cosmetics and other products.
How it works
In a cosmetic product, CI 45405 simply imparts a red hue. It does not interact with the skin or provide any skincare benefit; its sole purpose is aesthetic.
Pros
Vibrant color payoff
CI 45405 delivers a bright, consistent red shade that stays true in various makeup formulas, from lipsticks to blushes.
Good stability
This dye is stable in many cosmetic bases, meaning the color won't easily fade or change over time.
Cons and cautions
Banned in the EU
CI 45405 is not allowed in cosmetics sold in the European Union due to safety concerns, which may worry consumers who prioritize regulatory approval.
Potential skin irritation
As a synthetic azo dye, it can cause irritation or allergic reactions in people with sensitive skin, especially around the lips or eyes.
Best for
- People who are not concerned about synthetic colorants in makeup
- Those who want a wide range of red shades in their cosmetics
Use caution if
- Anyone with sensitive or reactive skin
- Consumers seeking products free of controversial synthetic dyes
- Those who follow EU cosmetic regulations or prefer 'clean' beauty
Usage tips
Safety summary
CI 45405 has raised safety flags due to potential skin irritation and systemic toxicity in animal studies. It is banned in the EU but still permitted in the US and elsewhere. For most people, occasional use in small amounts is likely low-risk, but those with sensitivities or a preference for stricter regulations may choose to avoid it.
Research notes
Studies on CI 45405 have shown potential for skin sensitization and irritation. The EU's Scientific Committee on Consumer Safety (SCCS) has deemed it unsafe for cosmetic use, leading to its ban. Evidence is moderate but sufficient to warrant caution.
Common label clues
- Typical concentration
- Very low, typically less than 1%
- Regulatory status
- Banned for cosmetic use in the European Union. Allowed in the United States and some other countries, but subject to concentration limits and purity requirements.
- Common uses
- Lip products, Blushes, Eye shadows, Nail polishes
- Environmental note
- Synthetic azo dyes can be persistent in the environment and may raise concerns about water pollution during manufacturing.
Good to know
- CI 45405 is also used in some textiles and food packaging, but its cosmetic use is restricted in many countries.
- The 'CI' stands for Color Index, a global numbering system for colorants.
Common questions
What is CI 45405 in beauty products?
CI 45405 is a man-made red pigment used to give lipsticks, blushes, and other makeup their color. It's also known as Acid Red 1. Because it's a synthetic dye, it doesn't do anything for your skin—it's purely for appearance. Some studies have raised concerns about its safety, which is why it's banned in the European Union for cosmetic use, though it may still appear in products sold elsewhere. If you prefer to avoid controversial colorants, you might want to check labels for this ingredient.
What does CI 45405 do in a beauty product?
In a cosmetic product, CI 45405 simply imparts a red hue. It does not interact with the skin or provide any skincare benefit; its sole purpose is aesthetic.
Is CI 45405 safe for most people?
CI 45405 has raised safety flags due to potential skin irritation and systemic toxicity in animal studies. It is banned in the EU but still permitted in the US and elsewhere. For most people, occasional use in small amounts is likely low-risk, but those with sensitivities or a preference for stricter regulations may choose to avoid it.
Who should be careful with CI 45405?
Anyone with sensitive or reactive skin Consumers seeking products free of controversial synthetic dyes Those who follow EU cosmetic regulations or prefer 'clean' beauty
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.