Does Henna Affect Hair Dye? And Why?

Henna hair dye is a popular option for many people who want to color their hair but are wary of chemical processes. However, it is a messy process that doesn’t often deliver the results people want. For whatever reason people who have used Henna may wish to return to a chemical process and are wondering if the Henna in their hair will affect the dye or visa versa. The simple answer is, yes, henna and chemical dye will react with each other, and sometimes the results can be disastrous.

The Reactions In A Nutshell

• Henna Over Chemical Dye
  1. Your hair could turn the color of sewage. (ew)
  2. The henna could react and severely damage your hair.
• Chemical Dye Over Henna
  1. The henna will block any color and cause processing to fail.
  2. Your hair could go down in a fiery mess. (We aren’t kidding)

While not all of these occurrences will happen in every instance, they happen often enough that you need to be aware of them – and do what you can to stop them.

Don’t Let It All Go Up In Flames

Imagine dying a clients hair, or even dying your own hair, and suddenly seeing smoke rise from your previously beautiful locks. It may seem like an impossibility, but it has happened before, so often in fact that the web is littered with stories of worry and warning. Yes, if you have previously applied henna to your hair (usually within the last 1-2 weeks) and you apply a chemical process over it, there is a chance your head could erupt in flames.

This happens because some henna applications include metallic salts. They are usually found in henna that has additives and extra ingredients to enhance or change color. While metallic salts aren’t bad on their own – once they are mixed with the ammonia that is found in chemical hair dye the trouble starts.

It is actually this combination that causes every reaction between henna and chemical processes. Everything from hair melting, to being severely damaged, to sprouting every shade of green possible comes from these two bad boys getting in a fight. And while some of these reactions may seem terrifying – that is actually good news as it makes it easier to avoid.

If the henna you have used does not include any kind of metallic salts, you should be good to go. That said, some brands do not include them on the ingredient list, so it is always smart to perform a strand test before heading into the salon. If you have used henna with metallic salts wait 3-4 weeks (if not more if your grow-out isn’t driving you crazy) before heading in.

Most importantly, be honest with your hairstylist. Be upfront about having henna in your hair. They will know how best to handle it – and do any tests needed to make sure that your entire salon experience doesn’t go up in flames.

*We do not apply Henna at our school. Please be aware of any application of Henna before seeking a chemical service to avoid damage and being engulfed in flames. We are an anti-fire facility.