has a LOT of really useful information on their site, including what henna really is and is not, the dangers of using hair colorings with PPD, and henna formulations to help you get the color you're looking for. LOTS of useful information there. Other people have mentioned that site earlier in this thread, but it's fantastic enough that it bears repeating.Henna vs. Synthetic Hair Color
(I'm calling it synthetic hair color instead of chemical hair color because, let's face it, everything is a chemical, including water.)
Henna - that is, pure 100% henna, can safely be used over synthetically colored hair. Look for Body Art Quality (BAQ)
henna, which does not contain the metallic salts and is 100% pure henna.
Henna that has metallic salts added, when used over synthetically colored hair, can make that hair either break, turn green, or smoke. The problem is that the added metallic salts chemically react to the synthetic dye.
The metallic salts are added to either a. make the henna appear brighter green and therefore fresher or b. change the color your hair will turn from the application of the henna.
If you use BAQ henna, you can safely color over synthetically colored hair, or use synthetic hair colorings later. No need to chop hair off or grow it out. If you use henna with metallic salts, then it is not safe to use synthetic hair color.
The problem with henna is that if it's not labelled BAQ, then you don't really know what's in it. It can say 100% pure, but still have the metallic salts. I ran into such a box of henna at a local grocery store a few weeks ago. It said 100% pure, but on their web site, they say that it has "added mild chemicals". Well, no. Not the same. But there are no labelling requirements
in this country and in many, if not most, of the other henna producing countries.
That's why I suggest getting BAQ - Body Art Quality - only. That's the only henna that's guaranteed to be pure henna and nothing but the henna.Clear Henna and Black Henna and Red Henna
What's been called clear henna or neutral henna is actually senna or cassia (Cassia obovata), a whole other plant. What's been called black henna is either indigo (Indigofera tinctoria) or henna with PPD
(metallic salts, and very very dangerous to use). Henna, the real henna is from Lawsonia inermis.Is henna permanent?
Yup. On the hennaforhair site, she has a downloadable pdf - 6 MB, so fairly large, but so worth downloading and reading through - she explains the science behind henna and how it works.
In case you doubt her qualifications, let me tell you that she's writing her PhD dissertation on henna.
Also, to the poster who asked about not shampooing... There is a lot of information on no-shampoo cleaning methods and, well, really, pretty much everything you ever want to know about taking better care of hair, over at the Long Hair Community
. It's well worth spending time browsing around and reading. Lots of different methods of taking care of hair and lots of discussion and experimentation around it.