21 CFR § 73.2329 - Guanine.
(a) Identity and specifications.
(1) The color additive guanine shall conform in identity and specifications to the requirements of § 73.1329 (a)(1) and (b).
(2) Color additive mixtures of guanine may contain the following diluents:
(i) For coloring cosmetics generally, only those diluents listed under § 73.1001(a)(1);
(ii) For coloring externally applied cosmetics, only those diluents listed in § 73.1001(b) and, in addition, nitrocellulose.
(b) Use and restrictions. The color additive guanine may be safely used in cosmetics generally, including cosmetics intended for use in the area of the eye, in amounts consistent with good manufacturing practice.
(c) Labeling requirements. The color additive and any mixtures prepared therefrom intended solely or in part for coloring purposes shall bear, in addition to any information required by law, labeling in accordance with the provisions of § 70.25 of this chapter.
(d) Exemption from certification. Certification of this color additive is not necessary for the protection of the public health, and therefore batches thereof are exempt from the certification pursuant to section 721(c) of the act.