Today's public service post is about henna, which seemed a suitable topic while I sit around with green mud plastered into my hair and a bag on my head.
Henna has once again become a popular method of coloring one's hair. It has many advantages. It conditions rather than frying hair, it fades gracefully, it has a nice transparent quality that keeps it from looking too matte or all-one-shade. It also, however, has one major drawback as far as the cosmetics industry is concerned.
Henna is red. Just red. Only red. It's dye component is an orange red and no other color
Not everyone wants all red all the time, when they go to dye their hair, so the industry set out to remedy this lack.
There are two other botanicals that mix well with henna to produce other shades. One is cassia obovata, relative of the cinnamon tree. If you have ever bought "clear" or "neutral" or "gold" henna, it wasn't henna at all. It was cassia, which has a similar conditioning effect and results in a light gold color. Another is indigo, which, mixed with henna and/or cassia can produce many shades of brown and reddish brown. There are also a handful of other botanicals such as amla that the can produce shades like burgundy when mixed in.
None of these are dangerous, though I do consider them an exercise in false advertising, since some of them don't contain henna at all, yet are still marketed as such in order to take advantage of the fashionable and "natural" reputation henna has. All of them result in green mud to work into your hair, and have a conditioning effect. None of them are toxic, though some of the minor ingredients, such as tea tree oil, can cause a slight rash or sensitivity if it sits on facial skin for a long time.
Black henna is a different matter.
See above: henna is red. One of the common hair colors people want, however, is black. In order to produce black while still using henna, some cosmetics makers struck on the method of cutting the henna with the chemical para-phenylenediamine (PPD). This is where we run into problems, because PPD is well associated with both allergic skin reaction and immune system insult and, possibly, mercury build-up.
Have I mentioned that henna's other major market niche is as body paint? It's used to produce semi-permanent tattoos, the art of which is often extensive, intricate and beautiful. Painting substances containing heavy metals on one's skin... less beautiful. Really, I thought we'd figured this out already with the lead-poisoning thing two centuries ago.
"Black henna" is the source of consumer warnings against henna products. Fortunately, the dangers of PPD are getting increasing press, especially among henna's proponents who resent having their beloved plant blamed for the sins of a different chemical. This is most especially the case because it is
possible to get a true black for hair by dying first with henna and then overdying that with indigo, a fact which can confuse the casual browser or consumer.
Bottom line, if you ever wish to use henna to dye your hair, make very sure you read the ingredients label thoroughly. If the product purports to be gold or purple or blue or anything but very red, be aware that henna is probably not the primary or active ingredient. Of the companies that produce a variety of henna-based mixes, either powdered or in a cream suspension, Light Mountain and Surya are both fairly safe. Surya's pre-mixed creams do contain small amounts of commercial red/yellow/blue/etc. dyes in order, I believe, to tint the mix something close to the color it produces, which I consider quite foolish and pointless, so if you are, for example, allergic to Yellow no. 5, be careful.
Your very best bet is to mix it yourself. Try the Mehandi site
which has both extensive information and products for sale.