Is it normal for BAQ henna (Raj/Moroccan) to fade out throughout the months?

[SaveTheTapirs]

A few months ago, I've hennaed my hair with a basic paste (powder + distilled water). However, the color gradually fades/lightens throughout the months. Is this normal for BAQ henna as well?
If you have dark brown hair, how often do you have to reapply the henna over the length to maintain the desired color?

Another possibility is that you need to add a slightly acidic liquid to your mix to make the stain permanent. In Ancient Sunrise/Henna for Hair's ebook chapter 7, they explain that henna can sometimes fade when mixed only with water:

"The acidic paste maintains the hydrogen atoms on the corners of the aglycone, the intermediate form of the lawsone molecule. In acidic mixes of henna, the intermediate form of lawsone will migrate into the keratin in hair or skin, and darken as it binds permanently with the keratin by a Michael Addition.
If the henna powder is mixed only with water, the hydrogen atoms are not as well conserved. Henna mixed with water is more likely to fade from hair because unbound lawsone will gradually wash out of hair. Henna mixed with a mildly acidic mix will leave a stain in hair that is not only permanent, but will gradually darken, and continue to darken for years."
http://www.hennaforhair.com/freebooks/

There's a lot of info there. They have a really comprehensive list of acids and how different ones affect the result. For example, a lemon juice mix will darken a lot on hair, but a cranberry juice mix will not darken much, leaving hair coppery. So definitely strand test, as others have said, and decide if you're going to do roots only or a whole-head application, because henna on top of previous henna will darken your result as well.

Hope you can get something out of that. Good luck!

[Sharky]

Seconding this. Been using henna for years and I've always used lemon juice in my mix, never had any issues with fading, but almost everyone I know who uses just water, does. You can use slightly acidic herbal teas, a dash of ACV, even plain orange juice, I imagine; straight up, nothing-but-lemon-juice can be harsh on people's scalp and hair.