This had me scratching my head a year ago when my friend posed a question. It started a research session, and another, and another.
It would seem there haven't been a whole lot of studies done on itchy scalp (otherwise known as pruritus).
Nope, sorry. That's a complete and utter exaggeration.
The fact is – in the entire world of scientific examination and study – there isn't a single study to be found on itchy scalp.
Not a one.
I'll bet you're itching to know where we go from here, aren't you? (sorry, I just had to throw that in).
So, where does one go for information and help if they are experiencing itchy scalp from hair dye? I heard you think 'stop dyeing the hair', but let's – for a moment – pretend that isn't an option.
Dyeing For Relief
I asked a few hairdressers how they tackled the situation if a customer complained of itchiness from hair dye. Several of them gave me the same answer.
It would seem the nearest sugar bowl (or artificial sweetener bowl, if you will) contains a packet of itchy scalp relief. The artificial sweetener known as Sweet and Low is the favorite product for hair-dye-scalp-itchiness amongst American hairdressers.
Let's have a closer look at how it is possible for an artificial sweetener to help relieve itchiness on a scalp coated with hair dye.
The DyeWith permanent hair dye, it is possible to transform any natural hair color into the desired flaming red, deep black, chestnut brown, or platinum blonde shade – and it stays there until new hair grows out.
But to understand what causes itchiness from hair dye in the first place, we need to take a super-brief look at the chemical make-up of permanent hair dye (I promise it won't be too nerdy).
Permanent color hair dye consists of two main components: ammonia and hydrogen peroxide.
It is the ammonia's job to damage the hair cuticle enough to where the new color can penetrate. Yes, you read correctly – damage the hair cuticle. The pH of ammonia is 11.6.
It is the hydrogen peroxide's job to 'develop' the color. Peroxide has a pH of 6.2.
If this sounds like a harsh chemical combo that isn't very hair or skin friendly, then you are quite right. This alkaline solution can indeed be quite the irritant.
In general, a permanent color hair dye has a pH of about 11.
And Sometimes, There is PPD as wellSome hair dyes contain paraphenylenediamine (also known as PPD). This is a popular hair dye ingredient because it provides a natural looking result. Unfortunately, PPD is also harsh enough to warrant cautions, require strict rules, and even be banned for some uses.
For example, it is illegal to use PPD on the skin in most western countries (it is used in henna tattoo products). Used directly on the skin, PPD risks causing severe allergic reactions that may even result in lifelong sensitivity to perfumes, printers inks, dyes, and even sunscreens.
PPD is allowed in hair dyes – but only at a maximum dosage of 6%.
Recipe for ReactionsLooking at the components of permanent hair dye certainly gives an indication that scalp itchiness, irritation, and sensitivity is practically a given. It's no wonder some people have reactions from dyeing their hair.
And it's no wonder folks have been trying to find a solution.
Sweet ReliefHairdressers battling hair dye itchiness have been doing so successfully by adding artificial sweetener directly into the hair dye mixture. The most popular sweetener is available in a little pink packet labelled Sweet and Low.
I'd love to know who came up with this idea, but so far, no one seems to be taking credit.
Sweet and Low (and some other artificial sweeteners) consists of saccharin, dextrose and cream of tatar. When added to a solution (read: when they are dissolved), each of these ingredients have a very low pH
- Cream of tatar (potassium bitartrate): approximate pH 3.5
- Saccharin: approximate pH 2
- Dextrose: approximate pH 3.5 - 5
Except in CanadaIf you're in Canada – where saccharin is not allowed in food products – your Sweet and Low is made with sodium cyclamate, dextrose and cream of tatar. As Sodium cyclamate has a higher pH, I can't help wondering if Canadian Sweet and Low would provide the same relief the US version of this product.
The Untested Theory of Why it WorksSince there have been no studies - either on scalp itchiness or on relief-of-scalp-itchiness-caused-by-hair-dye, there can only be theories and speculations as to how and why these ingredients are providing help.
My theory: Considering how alkaline a hair dye solution is to begin with, it seems logical to me that lowering the pH is going to provide itch-relief. The addition of these artificial sweeteners is helping to neutralize the ammonia, resulting in a more scalp-friendly solution.
But then, that's just my theory. If you have another, please feel free to drop a comment below.
That the simple addition of these ingredients doesn't seem to be interfering with the quality or function of the hair dye makes me wonder why the heck the hair dye manufacturers haven't been providing more scalp-friendly products to begin with.
If it's really that easy to make the solution less irritating without sacrificing function, the manufacturers should be reformulating their products!
So, Does it Work?I cannot say from personal experience if adding Sweet and Low to hair dye stops itchiness. I can, however, relate my friends account. She regularly went through scalp-itching torture having her roots done until she discovered this solution.
She told me the artificial sweetener made 'all the difference in the world'.
I believe her.
It was she who asked if I could explain why adding artificial sweetener to hair dye works for itchiness.
I hope I have.
More About Scalp Itchiness and Hair DyeNCBI: The lack of studies on itchy scalp
Severe Hair loss after using hair dye with PPD
The Dermatologist: About Scalp irritation
Norwegian Institute for Public health: Undesirable effects from hair dye
DermNet NZ: Allergy to PPD
An account of how Sweet and Low helped itchy scalp