Synthetic Dyes vs Natural Colorants in Soap

Key takeaways

• Bright, uniform colors in soap usually come from synthetic dyes listed as FD&C, D&C or CI numbers.
• Clays, charcoal, roots, seeds and spices give softer, earthier shades.
• Lye changes many plant colors, so natural bars can look different from the raw ingredient.
• Mineral pigments like iron oxides are often lab made for purity, which is a reasonable choice.

Color is the first thing many shoppers notice about a bar, and it says a lot about how the bar was made. Bright purple swirls and electric blue usually mean synthetic dyes. Soft tans, sage greens and dusty pinks often point to natural soap colorants such as clay, charcoal and plant powders. If you want a chemical free soap, color is a quick clue, as long as you know how to read it.

Why color soap at all?

Honestly, color does nothing for your skin. Soap made from olive, coconut and shea oils is naturally a creamy ivory or pale gold. Color is there to look nice, to signal a scent, or to make a gift feel special. That makes it a good place to ask whether a given ingredient earns its spot.

Synthetic dyes: what they are and how to spot them

Synthetic dyes for cosmetics were originally made from coal tar and are now mostly made from petroleum. In the United States, these colors must be approved by the FDA, and most must be batch certified, which means the FDA tests each batch for purity. On labels they appear as:

• FD&C names, such as FD&C Yellow No. 5 or FD&C Blue No. 1.
• D&C names, such as D&C Red No. 33, approved for drugs and cosmetics but not food.
• Color index (CI) numbers, used on international labels. FD&C Yellow No. 5 is CI 19140, FD&C Red No. 40 is CI 16035 and FD&C Blue No. 1 is CI 42090.
• "Lake" after a dye name, meaning the dye is bound to a mineral base so it does not bleed.

Approved dyes are considered safe at permitted levels by regulators, and most people use them without trouble. Some individuals do react to specific dyes, and many shoppers simply prefer not to use petroleum derived colors on their skin every day. The main site's guide to synthetic dyes and coal tar colors covers the regulatory side in depth.

Natural colorants used in handmade soap

Colorant	Typical shade in soap	Notes
Kaolin (white) clay	Ivory, opaque	Very gentle, adds a silky feel
Rose clay	Dusty pink	A kaolin clay colored by natural iron
French green clay	Soft sage green	Fades a little over time
Activated charcoal	Gray to deep black	A little goes a long way
Turmeric	Golden yellow to orange	Too much can tint a washcloth
Annatto seed	Yellow to orange	Usually infused into oil first
Madder root	Pink to red	One of the few stable plant reds
Alkanet root	Purple to grayish blue	Shifts with pH
Indigo powder	Blue to denim	Can rub off if overused
Cocoa powder or coffee	Brown	Coffee grounds also add scrub
Spirulina or nettle	Green	Often fades toward tan

Clays do more than color, which is why we cover them separately in clay, charcoal and botanicals in natural soap.

Why natural colors look different in soap

Fresh soap batter is strongly alkaline, and lye changes many plant pigments. A few examples:

• Green herbs such as dried parsley or spinach often turn brown or khaki.
• Lavender buds look purple in the jar but turn brown in a bar.
• Alkanet may be purple in oil and gray blue in finished soap.
• Calendula petals are an exception and tend to stay bright yellow.

Light also fades most plant colors over months. So a naturally colored bar may look muted or change a bit on your shelf. That is normal, and it is a decent sign that the color came from a plant rather than a dye. Storing bars away from sunlight helps; see does handmade soap expire for storage tips.

Can natural colorants bother skin?

They can, though it is uncommon at the small amounts used in soap. Plant powders are whole materials, so a person with a known plant allergy should read labels as carefully as anyone avoiding a dye. Overloaded bars are the more common complaint: too much charcoal, indigo or turmeric can leave color on a washcloth or a tinted lather. A well made bar uses just enough to shade the soap, and the lather should look white or nearly white.

Mineral pigments and mica: the middle ground

Some colors sit between "synthetic dye" and "plant powder."

• Iron oxides (CI 77491, 77492, 77499) give reds, yellows and blacks. Cosmetic iron oxides are usually made in a lab rather than mined, because mined pigments can contain heavy metals. Lab made here means cleaner, not worse.
• Ultramarines (CI 77007) give blues and violets and are also made synthetically today.
• Chromium oxide greens (CI 77288 and 77289) give stable greens.
• Mica adds shimmer. Natural mica mining has been linked in investigative reports to child labor in some regions, so many makers choose synthetic mica (synthetic fluorphlogopite) or skip shimmer altogether. Also check whether a mica blend is coated with FD&C dyes, which many colorful micas are.

Mineral pigments are stable in soap, do not bleed and are approved by the FDA without batch certification. Many natural minded makers consider them reasonable. Whether you do is a personal call.

A note on how soap is regulated

True soap that is sold only as soap and makes no cosmetic claims is overseen by the Consumer Product Safety Commission rather than the FDA. Once a bar claims to moisturize or deodorize, it becomes a cosmetic and FDA color additive rules apply. Either way, a careful maker uses cosmetic grade colorants and lists them clearly. The basics are covered in how to read a soap label.

Shopping checklist

1. Very bright or neon colors usually mean synthetic dyes. Check for FD&C, D&C or CI numbers in the 10000 to 70000 range.
2. CI numbers starting with 77 are mineral pigments such as iron oxides, ultramarines and titanium dioxide (CI 77891).
3. Plant colorants should be named plainly: "turmeric root powder," "madder root."
4. Uncolored is always an option. A plain ivory bar is often the gentlest choice for sensitive skin.

How we approach color

We keep color simple and let the oils speak for themselves. Our Body Bar is built on olive, coconut, shea, castor and avocado oils with essential oils, and you will not find synthetic dyes on its label. For more ingredients worth questioning, see ingredients to avoid in soap.

From the ranch

Made in small batches, without the ingredients discussed above.

Questions people ask

What are natural colorants for soap?

Common natural soap colorants include clays such as kaolin, rose and French green, activated charcoal, and plant materials such as turmeric, annatto seed, madder root, alkanet root, indigo, cocoa and spirulina. Each gives a softer, earthier shade than synthetic dyes.

Are synthetic dyes in soap harmful?

Dyes approved for cosmetic use are considered safe at permitted levels by the FDA, and most people tolerate them. Some individuals react to specific dyes, and many shoppers prefer to skip petroleum derived colors that add nothing for the skin.

Is mica natural?

Mica is a natural mineral, but cosmetic mica is often coated with synthetic dyes, and some natural mica mining has been linked to child labor. Synthetic mica is a common alternative. Check the label for added FD&C colors.

Why did my natural soap change color?

Many plant pigments react to the alkaline conditions of saponification and fade with light over time. Green herbs often brown, and lavender buds turn dark. This is normal and usually a sign the color is plant based.

Sources and further reading

1. US Food and Drug Administration (FDA), Color Additives Permitted for Use in Cosmetics
2. US Food and Drug Administration (FDA), Color Additive Status List
3. US Food and Drug Administration (FDA), Soap
4. US Consumer Product Safety Commission, Regulation of soap products
5. Personal Care Products Council, International Cosmetic Ingredient Dictionary and Handbook

This guide is for general education and is not medical advice. If you have a skin condition, allergy, or are pregnant or nursing, talk with your doctor or a board certified dermatologist about the products that are right for you.