Acid Blue 9: The Blue Dye in Your Hair Color
Arin Editorial · how this is made
You've seen "Acid Blue 9" on a hair dye ingredient list. The same substance appears as E133 on food labels. What do we know about this synthetic blue dye?
What is it?
Acid Blue 9 is a synthetic dye developed from coal tar derivatives. It was first produced in the early 20th century. Trade names include Brilliant Blue FCF, FD&C Blue 1, and E133.
What does it do?
It provides color. In cosmetics, it creates blue tones in temporary and semi-permanent hair dyes. It is also used as a coloring agent in food.
What do regulators say?
The European Union lists this substance in Annex III of its cosmetics regulation. It allows a maximum concentration of 0.5%. The EU's scientific advisory body SCCS has reviewed it. IARC placed it in Group 3: 'not classifiable as to its carcinogenicity to humans'.
What do tests show?
Hormone receptor screens found no estrogen-like activity. Skin and eye irritation studies reported no significant irritation. But genotoxicity tests are mixed. Some studies are positive, others negative. This suggests the substance might affect genes, but it does not mean it causes cancer.
According to Annex III of the EU Cosmetics Regulation, Acid Blue 9 may be used up to 0.5%, a use approved after SCCS evaluation.
Don't panic if you see Acid Blue 9 on a label. The EU has set a usage limit and products must comply. Doing a patch test before using hair dye is a good habit. If you have sensitive skin or are pregnant, ask your doctor.
Sources
- EU Regulation (EC) No 1223/2009, Annex III
- IARC (International Agency for Research on Cancer)
- SCCS (Scientific Committee on Consumer Safety)
- EPA ToxValDB