Ingredient review

Acid Blue 1

INCI: CI 61585

A synthetic blue dye that adds color to cosmetics but offers no skincare benefits.

beautyskincarecolorant

In plain English

CI 61585 is a man-made blue dye used to give cosmetics a blue or blue-green tint. It doesn't do anything for your skin—it's purely for appearance. In small amounts, it's generally considered safe, but some people with very sensitive skin may experience mild irritation.

Review score

Safety, usefulness, and evidence

3.5Good
3.5/ 5

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
How reviews are scored

Quick decision guide

Useful, but context matters

Acid Blue 1 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Acid Blue 1.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

CI 61585 is a synthetic organic dye from the anthraquinone family, also known as Acid Blue 1. It is approved for use in cosmetics in many regions, including the EU and the US (as D&C Blue No. 4).

How it works

It works by absorbing and reflecting light in the blue spectrum, imparting a blue color to the product. It does not interact with the skin or provide any functional benefit beyond coloring.

Pros

Vibrant color

Provides a bright, stable blue hue that enhances the visual appeal of products like shampoos and bath gels.

Regulatory approval

Approved by major regulatory bodies (FDA, EU) for use in cosmetics at safe levels.

Cons and cautions

No skin benefit

This ingredient is purely cosmetic—it adds color but does not moisturize, protect, or improve skin health.

Potential irritant

While rare, some people with very sensitive skin or dye allergies may experience mild redness or irritation.

Best for

  • Anyone who wants a blue-tinted cosmetic product
  • People without dye sensitivities

Use caution if

  • Individuals with known allergies or sensitivities to synthetic dyes

Usage tips

Check the full ingredient list if you have known sensitivities to synthetic dyes.
Patch test a new product containing this dye on a small area of skin before full use.

Safety summary

Generally safe for most people at the low concentrations used in cosmetics. Rare cases of mild irritation or allergic reaction have been reported.

Research notes

Limited peer-reviewed research specifically on CI 61585 in cosmetics, but it is a well-established colorant with a history of safe use under regulatory oversight.

Common label clues

Typical concentration
Very low, typically less than 1%
Regulatory status
Approved for cosmetic use in the EU and US (as D&C Blue No. 4) with concentration limits. Always check local regulations.
Common uses
Shampoos, Bath products, Soaps, Lotions
Environmental note
Synthetic dyes can persist in water systems; however, cosmetic use is typically at very low concentrations.

Good to know

  • CI 61585 is sometimes listed as D&C Blue No. 4 in US products.
  • It is not the same as FD&C Blue No. 1 (Brilliant Blue FCF), which is more common in foods and drugs.

Common questions

What is Acid Blue 1 in beauty products?

CI 61585 is a man-made blue dye used to give cosmetics a blue or blue-green tint. It doesn't do anything for your skin—it's purely for appearance. In small amounts, it's generally considered safe, but some people with very sensitive skin may experience mild irritation.

What does Acid Blue 1 do in a beauty product?

It works by absorbing and reflecting light in the blue spectrum, imparting a blue color to the product. It does not interact with the skin or provide any functional benefit beyond coloring.

Is Acid Blue 1 safe for most people?

Generally safe for most people at the low concentrations used in cosmetics. Rare cases of mild irritation or allergic reaction have been reported.

Who should be careful with Acid Blue 1?

Individuals with known allergies or sensitivities to synthetic dyes

Research sources

FDA Color Additive Status ListOpenEuropean Commission CosIng DatabaseOpen

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.