What about henna over blue hair??

[BunnyBee]

Hi, my boyfriend is also in the process of growing his hair long (again, it used to be about waist length) and so I'm trying to get him to take better care of it so it can be shiny and healthy when he gets there
His hair has been dyed all sorts of colours and at the moment it's blue (manic panic) It was bleached a few times and now he wants to get his natural colour back, or as close as possible. He's fine with using chemical dyes but i'd rather he tried henna as his hair really needs all the conditioning it can get.
My hair was green when I signed up here! I used henna from lush and now it is a mid browny colour..

I had to do three applications to get that colour as lush henna is kinda weak i think.

To get to the actual question! Would it be possible to use henna/indigo to go from dark blue to dark brown in one application? I will be buying henna from hennaboy.co.uk. I've never mixed my own henna before so I don't know what I need to add and how strong it will be.
I wasn't so bothered trying it on my hair as an experiment but if I ruin his hair he'll never forgive me!
Has anyone had experience of hennaing over unnatural colours before? Is it a bad idea?!

Thanks

[mellie]

If it is already dark blue, then straight henna on top of that MIGHT make it dark brown in one application.

I would get some BAQ henna and do some test strands first, of course!

[Kirin]

Blue from manic panic does wash out, so be careful. If he is aiming for brown, it will work, but the manic panic will fade away in time, even if henna'd over.