Natural Henna does NOT contain any metallic salts

I was talking to an ex-hairdresser today and was so disappointed when she said she didn't like henna because she believes that "the metallic salts in henna cause your hair to break if you later use a chemical hair dye".  Spent ages trying to convince her that she must not have been using natural henna but some sort of mix.

100% natural henna is just crushed, dried leaves, nothing added.
100% natural henna does not contain any metallic salts.
100% natural henna does not break your hair if you use a chemical hair dye later (however chemical hair dyes may break your hair anyway, with or without the use of henna).
100% natural henna does not strip your hair but rather bonds with the composition of your hair.

Other positive effects of 100% natural henna can include:
* Boosts hair growth
* Treats dandruff
* Aids restful sleep
* Therapeutic and calming
* Detoxifying
* Soothes headaches, aches, and pains
* Cools scalp and skin & reduces temperature
* Fights infection