What Is It?

Guanine is a crystalline material obtained from fish scales. In cosmetics and personal care products, Guanine is used in the formulation of bath products, cleansing products, fragrances, hair conditioners, lipsticks, nail products, shampoos and skin care products.

Why Is It Used?

Guanine imparts a white color to cosmetics and personal care products. It also reduces the clear or transparent appearance of products and can be used in skin makeup for hiding blemishes.

Scientific Facts

Guanine used as a colorant is obtained from fish scales. It consists of two purines, Guanine and hypoxanthine. The Guanine content varies from 75 to 97% and the hypoxanthine content varies from 3 to 25% depending on the particular fish from which the crystals are derived. Guanine provides a pearly, iridescent effect when used in cosmetics and personal care products.

Safety Information

The Food and Drug Administration (FDA) lists Guanine as a color additive exempt from certification. It may be safely used in cosmetics, including those intended for use in the area of the eye, when it conforms to FDA specifications. Guanine may also be used in externally applied drugs, but not in oral drug products. Cosmetic Ingredient Review (CIR) has deferred evaluation of this ingredient because the safety has been assessed by FDA. This deferral of review is according to the provisions of the CIR Procedures.

All color additives used in foods, drugs and cosmetics in the United States must be approved by FDA and listed in the Code of Federal Regulations. In some cases, FDA requires that each batch of color produced for use in regulated products can be used only if it is certified by the agency to meet strict specifications. FDA maintains a laboratory especially for this purpose and color manufacturers must pay a fee to support this activity. FDA only approves colors after extensive review of all safety data and publication of the basis for its approval in the Federal Register.

You can find out more about FDA regulation of colors at:

Link to FDA Code of Federal Regulations for Guanine

Guanine is listed as CI 75170 in the Cosmetics Directive of the European Union (see Annex IV) and may be used as a coloring agent in all cosmetics and personal care products. When used in cosmetics and personal care products in Europe, Guanine must be called CI 75170.

Link to the EU Cosmetic Regulation:…

You can learn more about the regulation and labeling of colors at:…

More Scientific Information

As defined by FDA color additive regulations, Guanine consists of two natural purines, Guanine and hypoxanthine. In cosmetics and personal care products, Guanine functions as a colorant and as an opacifying agent.