• natural compounds or additives derived from the natural ingredient 
• synthetic chemicals 

What it is for and where

Cosmetics

It is a restricted ingredient as  IV/18 ( CI 14700) II/1341 (Ponceau SX; CI 14700: when used as a substance in hair dye products) a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009.

It appears in the form of a red powder. 

Safety

Ponceau sx was found to be carcinogenic in hamsters, but not in rats (2).

Since intestinal cancer is more common in industrialised countries, a possible connection may exist between the increase in the number of cancer cases and the use of azo dyes. Azo dyes can be reduced to aromatic amines by intestinal microflora (3).

Molecular Formula  C₁₈H₁₄N₂Na₂O₇S₂

Molecular Weight  480.42

CAS :4548-53-2

Synonyms 

• Red 4
• Ponceau SX
• E124
• C.I. Food Red 1
• C.I. Food Red 1, disodium salt
• FD and C Red No. 4
• Dye FD and C Red No. 4
• Food red 1
• Ponceau SX Lake
• 4R purple
• Crimson 4R
• EINECS 224-909-9
• 2-(6-Sulfo-2,4-xylylazo)-1-naphthol-4-sulfonic acid, disodium salt
• 4-Hydroxy-3-(2,4-dimet hyl-5-sulfophenylazo)-1-naphthalenesulfonic acid disodium salt
• disodium 3-[(2,4-dimethyl-5-sulfonatophenyl)hydrazinylidene]-4-oxonaphthalene-1-sulfonate

References____________________________________________________________________

(1) Chung KT, Stevens SE Jr, Cerniglia CE. The reduction of azo dyes by the intestinal microflora. Crit Rev Microbiol. 1992;18(3):175-90. doi: 10.3109/10408419209114557. 

(2) Kornbrust DJ, Barfknecht TR. Comparison of 7 azo dyes and their azo reduction products in the rat and hamster hepatocyte primary culture/DNA-repair assays. Mutat Res. 1984 Jun;136(3):255-66. doi: 10.1016/0165-1218(84)90059-4. 

(3) Chung KT. The significance of azo-reduction in the mutagenesis and carcinogenesis of azo dyes. Mutat Res. 1983 Apr;114(3):269-81. doi: 10.1016/0165-1110(83)90035-0.