Many people have heard of something called "Neutral Henna". However most people don't know what it is or why it may be used. The neutral henna that you may find in your local drugstore is not a good choice, as it may contain metallic salts which can be potentially dangerous to your hair.
Cassia Obovata is the true neutral henna. It can be purchased organically, and is a terrific way to add some shine, strength and a bit of thickness to the hair. I purchase mine from HennaSooq.
I use Cassia, also known as Senna, about once a month. It doesn't interfere with my hair colour, although for people with extremely pale blonde hair or silver hair, it's not a great option, as it does deposit a pale yellow colour to the hair. While it doesn't show on most people, it does show on very light hair, so be aware. However, some people with silver use Cassia for just this reason. And some blondes use it to warm up their colour.
Unlike regualar henna, Cassia is temporary and eventually washes out after a month or so. It works to condition hair by binding the hair with Chysophanic acid.
It's very easy to use, and only takes about an hour and a half from start to finish. It's well worth it if you feel that your hair needs more strength.
It is a very messy process though, so you'll need an old towel and an old shirt or robe, or a painter's smock.
Here is how I use Cassia. Despite the quantities that are often recommended on the online sites, I find that 100g is enough to coat my hair easily even when it's almost waist length. Obviously people with thicker of courser hair will need to use more.
First of all, I boil some water. I like to use distilled water, but tap water will do. I pour the green cassia powder into a bowl, and then slowly add the boiling water, while stirring constantly. Add enough water to make a pancake batter-like consistency. You may want to allow the Cassia to "develop" for 15 to 30 minutes, but I've found that it's not really necessary. I mix it and apply right away.
Now, I'm wearing my old shirt. (something that buttons, zips or wraps like a robe is what you need--you really don't want to remove a t-shirt over your head once the Cassia treatment is over). I apply the Cassia from the back of my head to the front, covering the scalp first and then working it through to the roots.
I then cover it in plastic and cover all of that with an old towel. There will likely be some yellowish-brownish staining on the towel. I leave the mixture on my hair for an hour to an hour and a half, and the treatment is done.
Now it's time to rinse out the Cassia. I have to tell you that this is not easy. I usually rinse, rinse, and rinse some more until the rinse water becomes clear. This can take some time. Then I take a bottle of inexpensive conditioner (Suave Naturals is my usual choice) and slather it on my hair and work it through. I may use up to a half a bottle of this conditioner for this purpose. I clip up my hair and then leave it as I do the rest of my shower routine.
Now it's rinse time. I rinse for as long as necessary. I usually rinse for at least three minutes.
As everyone's hair is different, you may find that your hair feels a bit dry after the Cassia process. I recommend putting a small amount of moisturizing conditioner on the hair as a leave in, and then when the hair is dry, lightly oil as usual. In a few days, when you're ready for your next wash, you might want to do a deep moisture treatment. For most people, the hair "normalizes" on it's own.
The result for this is something that I've found to be quite amazing. My hair feels fuller, more conditioned and looks shinier. It's a great treatment for anyone, but especially for anyone who has damage. It also has the added benefit of being an antifungal, which can really be of help to anyone with a flaking scalp or other scalp issues.
So give it a try. Unless your hair is very pale, there is no permanence to this treatment, and you may find that it makes a big difference in your hair's health.
I'm including a photo of what Cassia Obovata powder should look like. The photo is courtesy of hennasooq.com. If you see Cassia that's brown, it's just not the real thing.