Can Hair Dye Lighten Previously Dyed Hair? I Tested It

You may have heard a hairstylist say “color doesn’t lift color” before. What does that mean, and is it true? According to what us hairstylists are taught in school, regular hair dye isn’t supposed to be able to remove previous dye molecules. So instead, we are taught that bleach (or a color remover) is the only option for lightening permanent hair dye. But as a rule breaker, I like to put these rules to the test.

A few months ago, I tested whether high lift hair dye can lighten previously dyed hair because of the added ammonia in high lift. And since I achieved phenomenal results, I decided to test whether regular hair dye can produce results as well.

Why Hairdressers Say Hair Dye Doesn’t Lift Hair Dye

When hairdressers repeat this rule, they aren’t making it up. We are taught in school that it doesn’t work.

Additionally, we’ve also had experiences where our clients hair isn’t lightening, to then discover that they had permanent dye on it.

Once the hair has been permanently colored, even if the color fades, it’s still been permanently altered. That’s why it’s called permanent dye. The hair won’t go back to its natural state again until it grows out and is cut off.

However, hair color has advanced significantly over the years. The technology behind hair dye has dramatically improved, and a lot of old rules aren’t as black and white as they used to be. Tasks we thought were once impossible are now indeed possible and safe for the hair.

What Happened When I Tested Permanent Hair Dye on Previously Dyed Hair

For my experiment, I tested two different brands of hair dye, as well as a variety of different hair types, dye types, and hair color situations. I wanted to determine if and when regular hair dye can lighten previously dyed hair.

I chose two level 10 neutral dyes and mixed them according to the recommended ratios with 40 volume developer. Then, I let them process for a total of 90 minutes, reapplying more color after 45 minutes. This is something we often do with bleach when we want to get the color lighter, especially when using a low developer.

Initially I wanted to push for results to break the hard rule, so I put the swatches in a heating pad on high heat while processing. To my surprise, it worked. And noticably.

This made me wonder if the high heat was the driving factor here. So I went back and tested the swatches without any heat applied at all. And these results were rather inconsistent. Some of the swatches did work, while others were negligable.

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How Adding Heat Can Achieve Results, But is Risky

While the high heat added to the swatches did open the cuticle enough to remove the hair dye molecules, the hair was rather compromised. I never would apply high heat to a client for 90 minutes straight.

The swatches that had only been dyed once prior still felt intact. But particularly the swatches that had been previously bleached and then dyed dark again were severly damaged. The hair was literally crispy!

This is one reason why I am always preaching to do a test strand prior to coloring your whole head. No matter what color service you’re doing, a test strand is insurance to know exactly what is going to happen and if your hair can handle it or not.

Different hair reacts differently. Even hairstylists regularly use strand tests prior to a lightening service to help them determine the proper course of action.

Does the Brand Matter When Attempting to Lighten Hair Dye?

The two brands I tested were Pravana (chromosilk) and Wella (koleston perfect). I determined that Wella outperformed Pravana in each experiment, including my previous high lift experiment.

In the test with heat applied, both brands achieved about the same level of lift. Pravana may have been sligtly more. However, the Pravana swatches appeared more damaged than the Wella swatches did.

In the test without heat, Wella noticably lightened the hair I’d say 2-3 levels, whereas Pravana didn’t. It possibly faded the swatch a little, but it certainly didn’t noticably lighten it (see image above).

This tells us that there isn’t a consistent result across the board. So it’s hard to say that it either always WILL or WILL NOT work. It’s also unknown if even the Wella would have worked on box dye.

Factors That Affect Results

There are numerous factors that can affect the results you’ll get. Some considerations are:

• Previously bleached and dyed: Hair that has been bleached and then dyed darker will undergo significantly more damage when attempting to lighten it again than hair that hasn’t been as processed.
• Semi permanent vs permanent color: This method is not recommended for semi permanent color, as it can drive the stain deeper into the hair. Instead, use Dawn or Vitamin C to fade semi permanent dye.
• Developer volume: Higher volumes like 30 or 40 will generally produce more lift than 10 or 20 volume.
• Whether heat is applied: Heat can significantly increase your lifting power by blasting the cuticle open for better absorption. But this should be done with caution as it can damage the hair quickly.
• Brand of color used: Both the brand of the original dye that you’re lifting out AND the brand of high lift dye can affect the amount of lift you achieve.

Final Verdict: Is “Color Can’t Lighten Color” Always True?

I think it’s safe to say that from all three of my experiments on lightening hair dye with hair dye, that no, this isn’t always true and you could consider this rule broken. While it was likely true at one point, hair color technology has advanced significantly. Dyes are able to acheive better results than ever before.

However since my results were inconsistent across brands, this means that we can’t necessarily say that “dye can’t lighten dye” is entirely false either. Until chemists are able to definitively produce hair dyes across the board that will always lighten hair dye, no brand will advertise that they do.

It’s just not as black and white as it used to be.

As most things with hair, this topic should be treated on a situational basis. Determinie what course of action to take by performing test strands to ensure safe and effective results.

If you’d be interested in me testing this theory with box dye, let me know in the comments! And be sure to subscribe if you want to make everyday a good hair day!