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Indigo

Indigo is a natural dye that can be extracted from the leaves of Indigofera tinctoria and some other plants in the Indigofera genus. Currently, most of the indigo on the market is now produced synthetically rather than from the plant.

It is traditionally used as a textile dye and produces a deep blue. It is commonly used to dye denim for jeans.

Indigo as a cosmetic color additive

Indigo, either natural or synthetic, is not approved as a color additive in cosmetics. It is not approved for use is soap that is a cosmetic.

The Wikipedia article on indigo dye states that the indigo derivative, indigo carmine, is used as a food colorant and is listed in the US as FD&C Blue No. 2. While this appears to be true, it is important to keep in mind that:

• FD&C Blue No 2 refers only to a substance that has been tested and certified by the FDA.
• The same chemical substance, when it has NOT been certified by the FDA, is an unapproved color additive.
• When certified, Blue 2 is approved for use in food, drugs, and medical devices; it is NOT approved for use in cosmetics.
• Natural, plant-based, indigo is NOT approved for use in cosmetics.

Soap

When used in cold or hot process soap, indigo (synthetic or natural) can create a nice blue color.

If the soap is exempt from the definition of a cosmetic, the cosmetic color additive regulations do not apply to the soap; there are no specific restrictions on using indigo in a non-cosmetic soap. The primary requirement in that case is that the product is safe and not potentially harmful to the user.

In order to be exempt from the definition of a cosmetic, the soap must be:

1. The alkali salt of fatty acids (lye/oil soap)
2. Only marketed as “soap”

A melt and pour soap base that is detergent-based is always a cosmetic and should never use indigo as a color additive.

Any statements that the intended use is cosmetic (i.e., that it could improve the appearance or beautify – such as moisturizing or exfoliating) causes the product to become a cosmetic. The cosmetic regulations would then apply, and indigo in any form would be an unapproved color additive. The product would be considered adulterated and, therefore, be prohibited from being sold.

Soap product claims exfoliation (cosmetic) but uses indigo as color additive. Prohibited.