What Is A Soap Cap And Why Should You Use It?

Have you ever heard of the term, “soap cap”?

If you’re into hair color, you need to know what a soap cap is. Let’s talk about how you can use this awesome technique to your advantage.

There are a few different types of soap caps (also known as shampoo caps, or color balancers). In this post, I’ll explain what they are and how to use them.

If you are a DIY hair colorist, you should probably know how to use a soap cap to your advantage. This professional technique is the perfect way to freshen up your hair color, while doing minimal damage do your hair.

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What You Need to Get Started:

First things, first… you’re gonna need some supplies. Don’t worry, I got you covered.

I also highly recommend you follow up with a deep conditioning treatment to keep your hair happy. I LOVE the It’s a 10 Miracle Deep Conditioner for projects like this.

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1. The “Traditional” Soap Cap with Color

Preparation of hair dye. Isolated on white background

This type of soap cap can be used to refresh dull hair color.

To perform a traditional soap cap: 

  • Mix hair color with equal parts shampoo
  • Apply to the hair and thoroughly saturate
  • Process for 5-10 minutes
  • Rinse, shampoo and style as usual

This method works best if you want to freshen up your color without recoloring your hair.

For example, if you’re just touching up your roots, you can use this method to revive the rest of your hair without the extra damage.

It could also just be used to refresh color between applications. The added shampoo dilutes the color so it won’t darken the previously colored hair.

It also ensures even application, which is a must.

2. Soap Cap with Bleach and Developer

Portrait of beautiful young woman dyeing hairs - isolated on white

I use this soap cap technique reasonably often on my own hair, as it is beneficial for platinum blonde hair. It can also be called a “color balancer” or “bleach bath.”

I use it to freshen up my bleached hair after touching up my roots or even just to freshen up in between applications. It does a lot less damage than re-bleaching the hair over and over again.

You could also use this type of soap cap to lift color gently. For instance, it will take out most semi-permanent colors without doing extensive damage.

You could also try to gently lift darker colors without doing too much damage. The Paul Mitchell color line recommends doing this before any color service (when switching color lines) to create a “fresh canvas” for the new color.

To perform a color balancer, you need to mix equal parts bleach, shampoo, and developer. Like the previous form of soap cap, process for 5-10 minutes, then rinse and deep condition.

3. Soap Cap with Bleach, No Developer

Portrait of young beautiful woman washing her head

I honestly just learned about this type of soap cap yesterday, and it’s pretty much the greatest thing ever. You can mix powdered bleach with shampoo, and it will lift color out of the hair. Skipping on the developer cuts down the damage done to the hair.

Yesterday, my co-worker tried to tone her hair with Redken 8T (Titanium Hair Toner), which is silver for those of you that don’t know. Well…her hair quickly turned silver. We used this method of soap cap to lift the color out of her hair safely.

Scientifically, I am unsure of how the bleach works without peroxide; I think it has to do with the oxygen molecules from the water mixing with the bleach.

Anyways, believe me, it works, and it does very minimal damage.

Now you know…

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Have you ever used a soap cap to freshen up your hair color? Do you have any tips to add for other DIY hair colorists? I’d love to hear your feedback in the comments section below…

RELATED: How To Use A Hair Toner For Brassiness

48 thoughts on “What Is A Soap Cap And Why Should You Use It?”

  1. HELP, I dyed my hair with a different # color and it turned out dark, dark brown. I hate it, was suppose to be champagne blonde. Can I use the bleach and shampoo method to lighten it up? Help, I’m in hiding.

    • It’s possible but hard to say without being able to see your hair and without knowing all of the details. I would say that generally, you probably won’t get the results you want if your hair is a dark brown unless you’re planning to color it again after. I would say that your best bet is to lighten it and recolor it. Of course, the best course of action would be to have a professional look at it. Good luck! Let me know how it works out!

  2. I had bleach in my hair just in foils then I had brown on the bottom. A stylist put vibrant red in. I stripped it out and it turned it this awful orange color. I tried to put a cool ash color number 6 in my hair. It turned it this brassy gross color. I stripped it again. And it turned it to a orangish color. All of my hair. I want to get the red out of my hair. Can I use a soap cap to do that? Would bleach work. Or bleach with developer. What would using purple shampoo with the soap cap do?

    • You say “had.” Has she colored it? If so, soap cap probably wouldn’t be a good option unless you are going to color it again after. I would use a hair stripper. If she hasn’t colored her hair, I still wouldn’t do a soap cap. It’s best used to remove some color before another coloring service, taking out some toner or refreshing bleached hair. Hope this helps!

    • I never have and I’m not sure if you can or not. Certain bleaches shouldn’t be used under a dryer (read instructions) but I don’t know if it’s possible to do with bleach that is allowed to be used under a dryer. Maybe call the manufacturer hotline and ask.

  3. The original soap cap…when you say the color is mixed with equal parts shampoo: Do you mean the color that has been mixed with developer? Or just the color from the tube (or bottle) with shampoo?

  4. I have over frosted my hair and it looks brassey. Can I soap cap it with 511N for a few minutes to bring the gold down?

    • I cant say 100% since I don’t know what your hair looks like or what color you are using, but usually when it has N in the name, it is a neutral base. I don’t think a neutral base would do much to tone the gold. If your hair is slightly brassy, and you want it to go to a darker blonde, I think that would probably work, but it won’t actually tone out the gold. I would also make sure that you only let it sit for a few minutes and watch it the entire time, otherwise it might get too dark (I’m guessing it is a level 5). Good luck! Let me know if you have any other questions 🙂


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