OK, you've been waiting patiently...and here it finally is: the post about why anyone would want to put henna in their hair (aside from the color, of course!)
The color was actually the thing that kept me from trying it for as long as I did, because it is permanent, and I wasn't' sure if I was ready to commit to being a henna-head for the long term!
The red--at least in my case--is really bright at first but fades a bit with time. Of course the brightness of the red varies by your natural color and also how much henna powder you use and how long you leave it in, and some people with particularly dark hair do not get any color change, although they can still reap the other benfits of henna. If you'd like to see a gallery of before/after pictures, go visit this page!
So why do henna?
Short version: henna seals the hair shaft (totally coats it). If you recall the picture I posted of a hair shaft, you'll see why sealing it can be so helpful for fragile hair.
♥ Some people find it to have a drying effect, but I have not (although I live in a rainforest, so your results may vary).
♥ Some people feel their hair is less dry (because each hair is protected).
♥ Many people find that they get fewer split ends (I sure have--I've only found a dozen in the last year--and trust me I look!).
♥ Many people report their hair feeling/seeming thicker (because if each individual hair is coated, then each one is slightly thicker, and that adds up to the whole mass feeling thicker). I have definitely found that in my case.
♥ Pretty much everyone (so far as I know) agrees that it's strengthening.
♥ Many people report loss of curl--I haven't noticed that in particular, although my first time doing henna ended up being less than a month before we moved to Pelican, and the transition from Utah desert to Alaska rainforest drastically changed my curl situation anyway, so I don't know what might have happened if I'd been staying in one place...as you can see though, my curl is not gone (and in my opinion it's about the same as it has been my entire life--UT or WA or AK)
♥ Some people do it just for the color.
I have had healthier, smoother, shinier, less-tangly, stronger and (of course) redder hair in the year and a half I've been using henna than I ever did before. It seems to be growing faster, and it's now gotten longer than it has ever been in my life--I honestly believe the henna has made it strong enough to do those things. I am delighted! ☺ Hubby seems to find it sexy--when I first did it he called me 'Red' for two weeks, and when I mentioned last fall that I was thinking about doing another henna treatment and he said "ooo, let me get it for you for christmas, ok?! I like the henna!"
There is a lot of henna info on LongHairCommunity, but I actually first learned about it from my friend Laminathegreat on a NaturalLDSMoms yahoo group. She recommended HennaforHair and I just poked around there for a while and kinda figured things out myself.
One of the things I really like about H4H is that it has the before & after gallery (which I linked above). The photos there were submitted by dozens of people who have henna'ed their hair, and they each include info about how much they used and how long they let it sit... So you can find someone with a similar natural color to yours and get somewhat of an idea of what your hair would be likely to do (what color it would turn) if you do henna.
H4H also has a list of links for good places to get henna for your hair. They recommend using body-art quality henna (which is more expensive, but the best quality). The particular place where I bought mine (HennaCaravan) has body-art quality henna that is a couple of years old--older than ideal for body-art use, but sufficient for hair. It's still the high quality henna, it's just past its prime, and thus the price is reduced.
So, if you're thinking about doing it yourself, you probably want the info about how much to use and how long to leave it in, right?
I can't tell you. It's different for everyone.
The general guideline I read was 100 grams for every 10 inches of hair. I have thin hair, and have used only 50 grams per application. The first time I chose the smaller amount because I was nervous about how much it would affect my color, the second time I only had 50 grams left (I had purchased a 100 gm box). This last time I prepared 50 grams out of habit, but I did notice that while there was plenty for the top of my head, there was not much left for the length of my hair, so next time I may try 100 grams.
As for how long to leave it in, again, a general guideline is 30-60 minutes. The longer you leave it, the more color you'll get. The first time I was nervous and did just 30 minutes. The second time I was bolder and did 60. Last month I'm not sure I even timed it very well, I just left it in for around an hour. Or, if you're feeling really scientific, choose a lock of hair from somewhere discreet (such as along your neck) or *gasp* cut off a lock of hair (or gather the trimmings after a haircut), and actually treat that lock with henna, keeping track of how long you treat it for, and noting what color it turns. I was too impatient to do that and just jumped in with both feet, (making guesses based off the information on the gallery page). My results matched my expectations based on what I'd read/seen at H4H. This is why I recommend visiting the gallery page--you can read what others did, how much they used, how long they let it sit, and see what colors resulted.