The Connection Between Itchy Scalp, Hair Dye, and Artificial Sweeteners


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.

Zipola.

Yes, really.

I'll bet you're itching to know where we go from here, aren't you? (sorry, I just had to throw that in).


Dyeing For Relief

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.

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 Dye

With 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 well

Some 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 Reactions

Looking 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 Relief 

Hairdressers 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 Canada

If 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 Works

Since 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 Dye

NCBI: 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

Comments

Signe said…
Do you know if adding this sweetener will affect to colouring results? I was wondering it might if you are changing ph levels?

And no you have any advise what might help itchiness if you are not dyeing your hair with commercial hair colours? I've a very itchy scalp, that is better when I started to use my own shampoo bars and stopped dyeing my hair, but it is still itchy.
Jenn in GR said…
Interesting article! Sweet and Low? That's cray-cray. How about if one has itchy scalp, but does not use permanent color, or only uses semi-permanent color a couple of times a year? Im asking for a friend.... ;)
Olivia J said…
I use Sweet and Lo in haircoloring. Even though there is really no substantial proof, but people say it acts like and anti-histamine. I add anywhere from 2 to 6 packets depending on the haircoloring and this could be any type from permanent to demi-permanent. I also have to say, with permanent and demi permanent haircolor, itchiness will occur because of the peroxide burns on the scalp. If you ever got haircoloring peroxide on your fingers, the burn is slight but annoying; I always sprayed vinegar to neutralize the burn.

Lise M Andersen said…
Hi Signe - As far as I understand, adding the sweeteners does not affect the quality of the colouring.

As for battling itchiness on the scalp - Do you make your own products? If so, you might try a combination of these ingredients: lavender, panthenol, aloe vera, peppermint (in small amounts, peppermint can be quite soothing).

Best of luck with it - and do let me know how it goes!
Lise M Andersen said…
Hi Jenn in GR - Yup, it is definitely something that had me wondering about as well. Again - there are no studies on this, but there does seem to be a consensus that it works.

I believe the sweet and low is equally soothing in semi permanent colours as well -Check Olivia's comment below where it looks like she has added this to semi permanent colouring as well
Lise M Andersen said…
Hi Olivia - Wow - you've really had this issue up close and personal - this is some interesting input. I'm curious as to the vinegar spray - does this affect the hair colouring in any way?
Signe said…
Hi, Lise! I actually don't use much more than my home-made shampoo bar and vinegar rinse anymore, and sometimes I dye with henna. But I'll try those in some form - in shampoo bars it will take long time before I can test them, but I'll try.
Anonymous said…
Adding artificial sweetener such as sweet and low has not helped me in the least. If you are allergic to permanent hair dye that has PPD in it nothing is going to help except stop using the dye....so very sad
Lise M Andersen said…
Hi Anon - I'm sorry to hear you haven't had success with this. You are absolutely correct in that an allergy to PPD cannot be helped 'after the fact'.
Y Schaefer said…
Just dyed my hair 3 days ago and used sweet n low (3pkts) and amazing no itch, but, of course the minute you mentioned this I itched not as much as before, it really works...
Lise M Andersen said…
Hey there Y Schaefer - great to hear that this worked. Did the color come out as you expected as well?
Melinda Roller said…
FYI...I know someone that puts 2 packets of sweet and low in her shampoo, mix well. And her hair is thickening up. The lady's in my family is going to try this immediately
Lise M Andersen said…
Hi Melinda - oh that's interesting! It would be interesting to investigate this in more detail.
Jenny Mertes said…
I've suffered from a severe PPD allergy for years. My hairdresser tried doing foil lowlights, but even the tiny bit of dye touching my scalp with foils made me break out in a horrible, itchy, welty massive reaction. A tiny drop of dye in my inner elbow (patch test) would cause a one-inch swollen, crusty welt that lasted a week. So I decided to go blonde because highlights and toner don't affect my skin at all, and I refuse to go grey. My hairdresser just heard about the Sweet and Low trick and tried it on me yesterday. I had her add lowlights back in (I really don't want to be blonde), and dang! No reaction. So I'm going to have her gradually try a bit more each time with Sweet and Low until I'm back to my normal color. This is amazing!
Marta Rosa said…
Have anyone tried any other sweetener or something like a soda or citrus?? Soda has a lot of sweetener and has low pH. Please write if anyone has tried.
Heather Behan said…
In case this may help those who suffer in the same way. I suffered from a very itchy scalp for years. It was all the time with no relief. I eventually discovered, after starting to make all my own cosmetics including shampoo and conditioner, that it was down to the pH of the product. I now have an itch-free scalp for the first time in years due to making my own hair products with a pH between 4.5 and 5.5. I add citric acid at the end and check with my pH meter. I'm guessing one could add citric acid to bought products to lower the pH but don't quote me!
Lise M Andersen said…
Hi Heather - great input! Thanks for sharing :D
:( said…
Hey guys, it really works! I am a hair colorist and I actually mix seeet in low on bleach, to be applied on scalp and it really helps with the echo g and burning and it doesn't alter the outcome of the color :)
Anonymous said…
Hey! Im in Canada and Sugar twin works! I could never leave hair dye in for as long as it should have been, due to burning and itching. I was so scared it was damaging my scalp. I added sugar twin (thanks internet)and voila! No more burning. I added 2 packets and was told that up to 3 will not cause a change in color.
Happy coloring.
Lise M Andersen said…
Hey there Anon - that's great! Thanks for sharing this :)
Noelle Hirst said…
My hairdresser uses one packet of sweet and low in my hair color and it really cuts down on my itchy scalp. It truly works and it does not affect the final result at all.
Lise M Andersen said…
Thanks for sharing Noelle!