So, I'm not quite happy with how dark my henna colour has gotten, therefore I decided to do a strand test to lighten it. I used 9% hydrogen peroxide on a hairball and 9% hydrogen peroxide plus cone free conditioner on the other hair ball (I kept some of my shed hair with the purpose of strand testing) and I left it on for 10-11 minutes. Sadly, there was no difference after I rinsed the hair samples and compared them to the before hair, so I'm posting the pictures here:
Before using the peroxide:
After:
Perhaps I should have left it on for longer, perhaps it just doesn't lighten henna, I have no idea, but there you have the results.