http://www.curlynikki.com/2008/10/im-henna-head.html and this one by Moptop Maven http://moptopmaven.blogspot.com/2010/04/henna-gloss-tutorial.html.
I did a lot more research and found that Henna has several benefits for natural hair and they include; strengthening the hair, adding shine to the hair, loosening the curl pattern, thickening the hair, aiding with growth, improving scalp circulation and increasing the health of the hair. I was sold! I went to a local Indian store called Pioneer Cash and Carry and purchased my supplies which consisted of some henna, oils (vatika, brahmi, amla), rose water, and coconut milk. When buying henna make sure you buy body art grade, other grades can contain PPD which can harm your skin.
Henna acts like a protein and my hair HATES protein so I add a ton of moisturizing conditioners and oils to my mixture which turns it into more of a gloss. Now I must warn you, henna is often used as a dye and will add a slight reddish tint to your hair. If you have very light colored or grey hair (not saying I do lol) it will turn them completely red/orange. Most people follow up with an indigo treatment to get their hair back to a dark black color. Here's how I make my Henna Gloss:
Don't add the Brahmi Amla oil until after letting the henna sit and getting ready to apply. As the henna sits, the color releases. I usually let my henna sit overnight but you can use it immediately. The next morning, I do the following:
This was a very quick overview of henna and ayurveda but I hope it helps!