Here's a list of colorants that do not need approval from the FDA to use:
Potassium sodium copper chlorophyllin (chlorophyllin copper-complex): Coloring dentifrices that are cosmetics NTE(7) 0.1% in combination with a list of substances.
Does this mean it can't be used at all in a formula even if not primarily as a colorant?
https://chemistscorner.com/the-challenges-of-formulating-a-natural-cosmetic-line/ this mentions it is allowed but that seems to be wrong.
Comments
Keep in mind, that while I have read the laws and regulations, I am not an expert. With that being said, when it comes to possible legal issues, I would recommend erring on the side of caution.