Cosmetic Chemistry: Different Types of Color Additive Used in Cosmetics
Friday, September 10, 2021
Aside
from fragrance, another common additives used in cosmetics are colorants. In
cosmetic chemistry, color additives refer to any substance that can change the
color of the cosmetics. Their primary purpose in the formulation is to make the
final product aesthetically appealing to the consumers. When it comes to
choosing the right type of color additives to use in your cosmetic formulation,
here are some factors that you have to consider.
Solubility
Color
additives can either be soluble or insoluble. For instance, water
soluble colors (e.g. dyes) are capable of dissolving completely in water.
Meanwhile, insoluble colors (e.g. mica) are only dispersible in either water or
oil. Basically, the choice of color additives will be dependent whether your
product is hydrous or anhydrous.
Application
FDA
(Food and Drug Administration) approved color additives are either D&C or FD&C. D&C colors
can be used in drugs and cosmetics, but not in food. On the other hand, FD&C colors can be used in food,
drugs and cosmetics. If your product is intended to be applied on lips, then
you must use FD&C colors.
Organic vs. Inorganic
Color
additives can either be organic or inorganic. The difference
between the two has something to do with their chemical composition and source.
Organic colors contain carbon and are often derived from coal
tars and other petrochemicals. Their greatest asset is their vibrant colors.
However, organic colors have a tendency to fade over time especially when
exposed to light. They are also more expensive than inorganic colors.
Inorganic colors do not contain carbon and are derived from
minerals. Unlike organic colors, they are more stable when exposed to light,
more economical to produce (cheaper) and have more color range available.
However, inorganic colors are not as vibrant as organic colors and are often
insoluble.
Now
that we know the various factors to consider when choosing a color additive,
let’s proceed in identifying the different types of cosmetic color additive.
1. Dye
Dyes
are organic, water soluble colors that produce vibrant colors. They are the perfect
choice of color to use in liquid soap because they are easily dissolved in
water without using a pre-dispersion agent. Since dyes have tendency to “bleed”
(color migration), they are not recommended for multicolored Melt & Pour
soap. Being an organic color, dyes have vibrant shades but they will morph and
fade over time especially when exposed to UV light.
2. Lake
Lakes
are organic, oil dispersible colors which are produced by combining FD&C
dyes with an insoluble metallic salt. Aside from oil, lakes can also be
dispersed in glycerin, propylene glycol and sucrose. Because of their bright,
non-bleeding colors and oil dispersibility, lakes are ideal colors to be used
when formulating lip balms, lip glosses (oil-based) and lipsticks. Compared to
dyes, lake colors are also more stable as they don’t fade over time.
3. Pigment
Pigments
are inorganic, oil dispersible colors that are very popular among soap makers
since they don’t “bleed” making them the perfect choice when creating multi-colored
soap. They are also very stable (fade-proof) and inexpensive color additives. However,
colors produced by pigments are not as vibrant as dyes and lakes. Pigments are
always created synthetically as mandated by FDA to insure that they are free
from toxic metals (e.g. lead) and safe to use in cosmetics.
Examples
of pigments are iron oxide, titanium oxide, zinc oxide, chromium oxide,
ultramarine, manganese violet, among others.
Here
are some useful info to know when using pigments:
- When using pigments in Melt & Pour soap (water-based), it’s important to pre-disperse them in either glycerin or 70% rubbing alcohol so that they will stay suspended on the soap.
- Manganese violet is unstable in products with high pH (alkaline) so they are not recommended in cold process soap making.
- Ultramarine pigments should not be used on lip products. Also, they are unstable in products with low pH (acidic).
4. Mica
Micas
are naturally derived from silicate minerals (e.g. muscovite). Synthetic micas
(known as fluorphlogopite) are also
available in the market. Compared to natural micas, synthetic ones are brighter
and have more uniform finish. In its purest form, micas are white in color.
Most often they are combined with titanium dioxide (to increase opacity) and
coated with either pigments or dyes to add color.
Micas
are both water and oil dispersible. They are also either organic or inorganic,
depending whether they are coated with pigments or dyes.
Micas
are popular for their ability to add sparkle to cosmetic products due to
optical reflection. They are best added to transparent Melt & Pour soap as it
makes the sparkle more visible. Micas are also non-bleeding colors so they’re
perfect for multicolored soap (except when micas are coated with dyes). In
lipstick products, micas can add shimmer but they’re not as pigmented as iron
oxides.
When
buying micas, make sure to take note of their particle size. The particle size
of micas is measured in microns, typically between 15 and 150 microns. The rule
of thumb is “the larger the particle size, the higher the luster (more sparkly)”.
This is also the reason why when making mineral makeup, it’s not recommended to
grind micas as it will reduce their luster.
In
summary, when choosing color additives to use in your cosmetic formulations,
you have to consider the solubility and application of your cosmetic products. The
most commonly used color additives are dyes, lakes, pigments and micas. Each
one of them has its own pros and cons. Most important of all, if you’re
planning to sell your homemade cosmetic products, then make sure to only use
FDA-approved color additives for cosmetics (which may vary from country to
country).
BONUS
I
found this helpful reference table that indicates application restrictions for each color additives (e.g. colors
that can’t be used around the eye areas). It also specifies the Color Index (CI) for each color.
Usually, we use the Color Index when specifying colors in cosmetic product labels.
For instance, red iron oxide is indicated in cosmetic product labels as CI 77491.
P.S.
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