Natural Colors in Cosmetics
Many consumers desire natural cosmetics. While some countries, including the US and EU, have natural colors in their positive lists these color leave a lot to be desired in terms of color properties and stability. The US FDA has no official definition of natural, but generally refers to them as ingredients extracted directly from plants or animal products as opposed to being produced synthetically. In the US natural colorants are covered in the Code of Federal Regulations Title 21, Part 73 and in Annex IV of the European Cosmetic Directive. 
Below is some information about natural colorants allowed for use in cosmetics in the US.
Natural Colorants for US Cosmetics
Annatto – Annatto is a yellow to orange colorant derived from the evergreen shrub Bixa oreallana. It is not stable with respect to light and in acidic conditions. Annatto is also used to color cheese, baked goods, and snack food.
Chlorophyllin CU Complex- This green colorant is produced from chlorophyllin extracted from alfalfa. The central copper atom in this complex is replaced with magnesium. It is stable with regards to light and alkaline conditions but will precipitate as a sodium salt in acidic conditions. Chlorophyllin CU complex is limited to use in dentifrices in the US.
Carmine – Carmine is chemical lake that has a unique blue shade red and stands apart from other natural colorants, which tend to be duller. It is derived from the extract of dried female cochineal beetles found in Peru. It takes approximately 155,000 beetles to make one kilogram of carmine. Carmine has reasonable light stability and it is not stable in acid conditions or temperatures about 60 C. And because it is a chemical lake, it will break down in strong acids or bases, liberating free carminic acid. Carmine finds use in eyeliner and eyeshade as no other red colorant is approved for this are in the US. Carmine is not consider when products claim no animal derived ingredients or cruelty free due to its insect origins.
Henna – Henna is a dye extracted from the henna plant. It is used to color hair and a temporary dye on the skin. Its use in the US is limited to hair applications and specifically prohibited from use on eyelashes or brows because of the concern for eye irritation.
β-Carotene – A yellow to orange pigment that is obtained from the fungus Blakeslea trispora. It has good stability with respect to light, heat, acid and alkali.
Caramel – Caramel is a brown colorant made by burning of sugar. It has excellent heat and light stability and stable in acid and alkali systems.
Guaiazulene - A derivative of azulene, a component of chamomile. It is a blue colorant that is approved for external use only in the US. At a cost of over $200 per kilogram, it has very limited use.
Guanine – Gaunine is a natural pearl pigment made from the scales of herring, sturgeon, or salmon fish. It is extremely fragile; the crystal structure can be damage easily to it must be handled with care in manufacturing. Guanine has excellent solvent and water resistance making it useful in liquid and cream products. Cost is also a limiting factor for this ingredient.
