I’m often asked about different ways to naturally colour lotions, so I conducted a fifteen-week experiment testing out ten different natural colourants to see what worked, and what didn’t.
Why ‘lotions’ specifically?
Formulations that contain water—like lotions—are a lot harder to colour naturally than anhydrous formulations (formulations without water). Because water is present, the emulsions are susceptible to microbial spoilage, which is something we don’t have to worry about with products like balms, salves, and anhydrous body butters. This spoilage potential can limit our colourant options as colourful ingredients can also be challenging to preserve. I’ve also found that natural colourants can fade and oxidize much faster in hydrous formulations than anhydrous ones.
- How do ten different natural ingredients perform as colourants for an emulsion at 1%?
- How does the inclusion of a chelator (Tetrasodium Glutamate Diacetate at 0.5%) change that performance?
I began by making two big batches of my Easy Natural Lotion for Beginners. Each batch was short 1% to allow room for adding different colourants. One batch was made as written, and one batch included 0.5% Tetrasodium Glutamate Diacetate—a natural chelator. The pH of each lotion was around 5.4–5.5.
I portioned out 29.7g lotion into glass prep cups and added 0.3g colourant ingredient to each: 99% lotion + 1% colourant ingredient.
Each colourant was added to a chelator’d and non-chelator’d portion of lotion, hand whisked to combine, and then decanted into a labelled plastic condiment cup. This resulted in 20 little cups of coloured lotion + 1 wee cup of control (the emulsion without a chelator).
I then left those wee cups in a box on a shelf in my studio for 15 weeks to see what happened.
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I tested 10 different natural ingredients, choosing ones that would impart some colour, and generally trying to test ingredients that are somewhat readily available and/or I’m asked about often.
- Activated charcoal
- Alkanet root powder
- Australian pink clay
- Black goji extract
- Carmine (ground powder)
- Coloured mica (Coho Shimmer)
- Hibiscus powder
- Indigo powder
- Sea Buckthorn fruit oil
- Turmeric liquid extract
Several of these colourant ingredients definitely would’ve fared better with a different usage rate or if turned into some sort of an infusion first, but I wanted to 1) keep the experiment as consistent as possible and 2) try a variety of ingredients and formats. I’m also frequently asked about adding powdered botanicals to formulations as colourants, so I wanted to show what happens when you do.
Click the images to enlarge.
The control emulsion remained stable throughout the 15 weeks.
To chelator or not to chelator? 🤔
Across the experiment, all of the non-chelator mixtures show some degree of separation at the bottom of the cup after 15 weeks while the chelator versions were stable. As chelators boost preservative performance, I believe this is likely due to the non-chelator version starting to spoil.
Activated charcoal is an insoluble fine black powder; at 1% it gave the emulsion a speckled dark grey appearance.
After 15 weeks the the colour appears to have remained stable for both versions, but the non-chelator version is separating at the bottom.
Alkanet root powder
From past experience with this ingredient, I think it would’ve created a more uniform final product if I’d infused it into the oil phase and strained it out rather than adding the straight powder to the lotion.
Adding 1% of the powder to the lotion created a slightly pink, speckled appearance.
After 15 weeks the colour has darkened, with the chelator version being darker than the non-chelator version. I suspect the darkening is due to the powder having more time to infuse the lotion as the colour appears more saturated. The non-chelator version has noticeable splitting at the bottom.
Australian pink clay
This is a soft clay with an earth-toned pink colour. Mine was purchased from New Directions Aromatics Canada, but they’ve since discontinued it. The pink colour comes from naturally occurring red iron oxide.
At 1% this clay gave the lotion a soft dusty pink colour. After 15 weeks the colour in both lotions had deepened a bit and taken on a whisper of a brown tint. The version without the chelator showed noticeable separation at the bottom.
Black goji extract
Despite the deep colour of the extract in the bottle, this at 1% extract just took the lotion from white to a slightly warm white.
After 15 weeks the colour appears to have remained stable, and there isn’t a noticeable difference colour between the chelator and non-chelator version. The version without the chelator showed noticeable separation at the bottom.
Carmine (ground powder)
Carmine is a natural vibrant red-pink colourant that has been used for centuries. It’s made from the cochineal insect, making this the only non-vegan ingredient in this experiment.
I used the powdered version knowing it would be way too much for a lotion at 1%, and I was right—it ended up being more of a sorta-cream-blush than a lotion 😂
The lotions coloured with carmine were bright pink and speckled; I suspect the speckles could be avoided by using about 1/10th of the amount and pre-dispersing the carmine in a smaller amount of liquid earlier in the making process.
After 15 weeks both the chelator and non-chelator version were still vibrant, but I think the one with the chelator was a bit richer/deeper. The version without the chelator showed slight signs of separation at the bottom.
Coloured mica (Coho Shimmer)
The mica I used for this experiment was a lovely pink colour, made from a blend of mica, red iron oxide, and titanium dioxide—all insoluble ingredients. Coloured micas can be coloured with all kinds of ingredients, including synthetic dyes and carmine, so be sure you’re checking the ingredient lists for your micas so you know what you’re using.
At 1% this mica gave the lotion a bright, even colour that was true to the dry mica. It remained stable throughout the 15 weeks, and I couldn’t see a difference between the version with and without the chelator. There was no splitting.
I used a relatively fine hibiscus powder that gave the lotion a grey-ish pinky/purple colour with lots of speckles. This ingredient almost certainly would’ve worked better as a colourant if infused into something and then strained out, but I included it as a powder as I have been asked about using hibiscus powder as a colourant before.
After 15 weeks the colour had faded. The version without the chelator was a greyish brown and showed noticeable separation at the bottom. The version with the chelator was more of a warm brown and was not separating.
I purchased indigo powder for use in soap making, but it’s such a beautiful colour I figured I’d give it a try here! As you might’ve guessed from its name, it is a rich, dark blue.
It coloured the lotion a lovely grey-ish blue with some speckles; this is another ingredient that almost certainly would’ve performed better as an infusion.
After 15 weeks the colour appears to have remained stable, and there isn’t a noticeable difference between the chelator and non-chelator version, with no splitting.
Sea Buckthorn fruit oil
It gave the lotion a soft orange colour. After 15 weeks the colour appears to have remained stable, and there isn’t a noticeable difference between the chelator and non-chelator version, with very slight signs of splitting in the non-chelator one.
The turmeric extract I used for this experiment is from Voyageur Soap and Candle Co. with an INCI of “Curcuma Longa Root Extract (and) Propanediol“. It’s a deep orangey yellow, and imparted a bright yellow colour to the lotion that reminded me of Easter.
After 15 weeks the colour appears to have remained stable, and there isn’t a noticeable colour difference between the chelator and non-chelator version, but there is some slight separation at the bottom of the non-chelator one.
Conclusions & takeaways
- It’s a good idea to include a chelator with this formulation/preservative (Euxyl™ k 903) if you’re including any extracts or botanicals as many of these additions seemed to overwhelm the natural preservative when a chelator was not included.
- It would be interesting to replicate this experiment with a version of the lotion preserved with Liquid Germall™ Plus as I’m much more familiar with that preservative, and I suspect it’s stronger than the Euxyl™ k 903 I used in this formulation. Would we still need a chelator? Hmmm.
- Try infusing botanicals into a medium like oil, water, or glycerin rather than adding straight powdered plants. This will likely give a result closer to what we saw with the Black Goji extract, meaning you’d probably need to use more than 1% to get a noticeable colour in the finished emulsion.
- Coloured micas are a really easy way to reliably colour formulations.
- Indigo and alkanet look like promising botanical/herbal options, but would likely be better utilized as an infusion.
The Coho Shimmer mica, black goji extract, and turmeric extract were gifted by Voyageur Soap & Candle.
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