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FDA approved colors for shampoo
Hi!
A few weeks ago i made another post https://chemistscorner.com/cosmeticsciencetalk/discussion/help-help-how-to-use-color-cosmetics/#post-244378 where I asked for help with neutralizing a yellow tone in a shampoo. In that post, I received helpful advice, mainly on color science and FDA-approved colorants.
However, I still have a few questions regarding FDA-approved ingredients—specifically, colorants. I don’t live in the U.S., but my product will be sold there. I’ve already checked my shampoo formula and confirmed that all the base ingredients are FDA-approved.
The problem is, when it comes to colorants, I’m unsure which ones are safe for use in shampoos. The FDA lists colorants as approved for either “external use” or “eye area” use. In my mind, since shampoo can run down the face and possibly make contact with the eyes during rinsing, I’ve only been using Blue 1, Red 40, Yellow 5, and Green 5—since these are the only ones approved for use in the eye area.
Am I right to be this cautious, or is it acceptable to use colorants that are approved for “external use” only?
On a totally different note—regarding the neutralization of yellow tones in my shampoo—I’ve done a few color tests using purple, and I’ve noticed that while it does neutralize the yellow, it turns the shampoo a slightly dark, greyish tone. It definitely works, but it ends up looking a bit dark, and I’m aiming for more of a pastel tone.
Is there any way to prevent this?
Also, what’s your opinion on using zinc oxide or titanium dioxide? I haven’t used them because my research suggests they tend to sediment at the bottom. But does that actually happen, or is it possible to successfully suspend them in shampoo? (I consider this ingredients just to make the base more white).
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Help! Help! How to Use Color Cosmetics - Chemists Corner
Lately, I've been formulating a shampoo for a client, and I've finished the base part. The thing is, she wants the shampoo to be available…
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2 Replies
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I forgot to ask this, but if someone has experience with mixing colors—for example, to make purple you need red and blue—when creating the color, do you mix the pigments first, or do you make solutions at a certain concentration and then mix the solutions? Which method is better? I appreciate any tips!
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Hi Natasha 🙂
There are several ways to solve this problem:
If the desired result is colorless, colorless ingredients must be used. In a pinch, you can “bleach” a formula with a reducing agent such as sodium metabisulfite, but the collateral damage is that this tends to disrupt the molecules.
Another solution would be to mask the yellow with a specific color, which would allow you to not touch your surfactant system, your perfume or your preservatives - or whatever the responsible ingredient is.
Regarding TiO₂/ZnO, these are pigments, not dyes. They would cloud your formula, and without a solid suspending agent, they will sink to the bottom of your bottle within a few hours at most.
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