Can you dye over Henna?

I got an excellent question today and wanted to address it. The question was "Can you use chemical dye over Henna?".. 

Here is my personal experience..  I've been dying my hair red for a very long time. When I first found Henna, I still had a box of chemical dye that I had not used yet. Being the frugal person I am I didn't want  to waste it, so I decided to use it. 

Here is your disclaimer! Henna is permanent , and really can't be taken out of your hair.  If you dyed your hair with Henna, and it's darker than your natural color, you CAN NOT try to lighten it. You'll only end up with a mess, and probably damage your hair.  Because Henna is all natural, your hair soaks it up like a sponge and the color sticks to the follicles of your hair.  Putting bleach in your hair will cause a reaction and make your hair turn green. If you do not like the color Henna gave you, I would suggest trying another Henna product  that will give you another color. Henna King is where I buy all mine, and they have a variety of different colors to choose from.  Also if you dye over it with the same color,  it will be darker the 2nd time around. Best thing about Henna is you can dye it as many times as you want, because it's natural and won't harm your hair! Once Henna has oxidized and reaches its final shade the color will be ingrained into the strand of hair.  Henna will not get brassy like many other hair dyes do, and it has very little upkeep.  The color will remain the same until it's redyed. The only real way to get rid of the Henna in your hair is to grow it out or cut it off. 

However in my experience, once your Henna hair has settled, and has started to reach its final color shade, then you can use a chemical dye over it (darker only). In my case I had a box of Scarlet red chemical dye that I hated to not use.  So after my hair started to grow out, I did use the bright red dye, and it came out very nice.  My hair did begin to fall out again, and I could feel the difference because my hair did not have the body or the fluff that you get with Henna, but it was the last time I ever used chemical dye on my hair, and the only dye that will ever touch my hair again will be Henna!  

So to answer this question due to my own experience, as long as the chemical dye is similar in color, it should be okay to dye over. I think if you had used red henna, and wanted to go brown you'd probably end up with a more auburn look just because the Henna will shine through. Since my hair was red with Henna, going a darker red did not really make a difference when the red highlighs showed through. 

This is not to say it's okay to try Henna, then go out and dye over with chemical dyes. You have to be very careful when using Henna, and know you are ready for the serious permanent color you're getting. Always do a strand test just so you can be sure you like the color first. 

Hope this answers your question on if you can dye over your Henna. It's not recommended, but it can be done and is possible if done correctly.