Organic Indigo Leaf Powder
Indigofera tinctoria
Green Powder, Blue Hair —
and What Happens in Between
There is no blue in this powder. What the leaf holds is a colourless precursor that only becomes blue after water releases it and air finishes the job — and most of that happens after you have rinsed the paste off.
Once you know what is going on in those hours, one powder can do a lot: on its own, over henna, or mixed with it. This page explains the chemistry, and shows what we saw when we tested it.
Mix
1 : 3
powder to water, by weight
Paste pH
6.28
our measurement, at 80.6°F
After rinsing
Stay damp
it decides the colour
How It Colours
Three Stages, and One Side Road
Indigo is not a dye you put on your hair. It is a dye that forms on your hair, from something colourless, over several hours. Knowing the stages is what lets you steer it.
Indican
In the dry leaf · colourless
The leaf stores its future colour as indican, a sugar-bound precursor. Nothing about it is blue. It stays like this until water arrives.
Indoxyl
In the paste · pale, water-soluble
The enzyme splits the sugar off, releasing indoxyl. Because it dissolves in water, it can move into the hair. It is unstable, and it does not stay indoxyl for long.
Indigo
On the hair · blue, insoluble
Oxygen pairs indoxyl molecules into indigo. Indigo does not dissolve in water, so once it has formed in the hair, it stays there.
The side road
Isatin
Yellow by-product
Some indoxyl is oxidised further instead of pairing up, and becomes isatin.
Indirubin
Red-violet
Isatin combines with indoxyl to make indirubin — same building blocks as indigo, a different shape, and red instead of blue.
Why it looks green when you rinse
At the rinse, the reaction is only part-way through. Blue indigo that has already formed sits alongside pale yellow material that hasn't finished — and blue over yellow reads green. It isn't a colour the hair keeps; it is the middle of a process.
Why it sometimes turns purple
Indirubin is red-violet, and the amount of it that forms is not fixed. A US patent on indigo hair dye describes it directly: the amount can increase depending on the conditions the hair is dyed under, pulling the result from blue towards reddish purple. Our own drying test, below, shows one of those conditions.
Sources: the indican → indoxyl → indigo pathway and the isatin → indirubin side reaction are standard indigo chemistry. The hair-dye observation is from US Patent 6,849,096, Hair dye and hair-dyeing methods using the same.
What We Tested
Same Paste, Same Hour.
Three Ways of Drying.
We coloured three swatches of white hair identically, rinsed them, and changed one thing: how long each stayed damp afterwards. Then we photographed them at 90 minutes and again at 24 hours.
Paste
1 : 3 by weight
Paste pH
6.28 at 80.6°F
On the hair
1 hour
Room
80°F
90 minutes after rinsing. Still green, all three — but already different.
24 hours later. All three darker — and pulled in different directions.
| After rinsing | Damp for | At 90 minutes | At 24 hours |
|---|---|---|---|
| Fan, room temperature | 5 min | Yellow-olive | Reddish plum |
| Left to dry on its own | 60 min | Green | Violet-navy |
| Wrapped in a towel | 90 min | Blue-green | Blue-black |
Drying doesn't stop it
All three kept changing after they were dry — even the one that was dry in five minutes. The colour you see at the rinse is not the colour you'll have.
It changes which way it goes
The longer a swatch stayed damp, the further it went towards blue. The one dried fastest went red-violet instead. The first hour or so after rinsing set the direction.
Why the towel won
A towel doesn't dry hair faster — wrapped up, it slows evaporation, keeping the hair damp for longest. That gave the indoxyl the most time to become indigo.
So: after rinsing, keep it damp and leave it alone
Wrap in a towel. No hair dryer — warm or cool. The red-violet the fast-dried swatch turned is what shows up on heads as an unwanted purple, and we have not found a way to reverse it once it has formed.
One test on white swatch hair, one swatch per condition, photographed indoors under the same light. The red-violet shift is consistent with more indirubin forming, as the patent above describes — but we have not measured the pigments themselves, so treat that as the likely explanation rather than a confirmed one.
The Most Common Use
When a Brown Came Out Too Orange
Most people who buy indigo on its own already coloured with one of our browns — Dark Brown, Brown or similar — and got a result warmer than they wanted. Indigo on its own, applied over the top, is how you take some of that orange back out.
Why a brown can come out orange
A brown like Dark Brown or Brown is henna and indigo together. Henna gives orange; indigo lays blue over it; the two together read brown. When it comes out orange, the henna did its part and the indigo didn't finish.
The usual reasons
- The hair was dried quickly after rinsing — see the test above
- Grey or porous hair, which takes henna readily and shows its warmth most
- Too short a time on the hair, or paste that dried out while it was on
How to use it over an orange result
You can do this the same day, straight after rinsing out the first colour, or later once you have seen how it settled. Either works.
-
1
Wash, skip the conditioner
Towel-blot until damp, not dripping. Conditioner and styling products keep the paste off the hair.
-
2
Mix 1 part powder to 3 parts water
By weight, warm tap water. Keep stirring for two to three minutes — it looks too dry at first and softens on its own. Mix it only when you are ready to use it.
-
3
Apply where the orange is
Work it in generously, roots first. Concentrate on the warm areas rather than covering every strand the same.
-
4
Film, then leave it on
Wrap in kitchen film so the paste stays wet, and leave it on for one hour.
-
5
Rinse with water only
No shampoo. It will look green, or darker and greener than you expected. That is the middle of the reaction, not the result.
-
6
Wrap in a towel and wait
This step decides the result. Keep it damp as long as you comfortably can, no dryer, no shampoo for 48 to 72 hours. Judge it on day three.
Don't dry it fast
In our test, the swatch dried in five minutes went red-violet, not blue. Over hair that is already orange, that reads as red or burgundy — the opposite of what you are trying to do.
Keep it off grey that didn't take
On white hair with no warmth underneath, indigo alone went blue-black in our test. It needs orange beneath it to read as brown. Strands the first colour missed will look blue.
Start with one round
How far it moves depends on how orange you are and on your hair. Plant colour builds up rather than resetting, so if it is still warm after three days, a second round goes further. Going too far is harder to undo than not going far enough.
Try a strand first
A small hidden section, same method, judged after three days. It is the only way to see what indigo will do over your particular orange before it is on your whole head.
Indigo only ever adds colour; it cannot lighten. If the aim is to get lighter, rather than less orange, this won't do it.
If Something Looks Wrong
Three Results, Three Explanations
Wait until day three before deciding anything — indigo is still moving until then. If it has settled somewhere you didn't expect, start here.
It went purple
Usually the hair dried too quickly after rinsing — the red-violet side of the reaction, shown in our test above. What causes it, and what to do next.
Read more →It went blue
Most often indigo landed on hair with nothing warm underneath — grey the first colour missed, or indigo used on its own. How to bring it back towards brown.
Read more →It's still orange
If one round of indigo wasn't enough, or you haven't tried it yet. Why browns come out warm, and the options besides indigo.
Read more →Before you use it for the first time
A small number of people react to indigo. Patch test a little paste on your skin 48 hours before a full application, and don't use it if you have ever reacted to indigo or to a plant-based hair colour. If you are under medical care, check with your doctor.
Not sure whether indigo is the right fix for your result? Send us a photo at info@radicousa.com — we answer ourselves.