The oil is taken from the Indian gooseberry which is a tree native to India. It offers special proponents and fatty acids that strengthens the hair, moisturizes and stimulates the scalp, elevators grays and dry strands, and encourages hair growth.
This is the only brand I've used, Dabur Amla shown below. It does wonders for my coils. My scalp can dry out easily, but this does the job, by simply doing a treatment once to twice monthly. You can however use it more often, depending on your hair needs.
My preference is to saturate my hair with the oil and apply a plastic cap for two to three hours. I then follow the oil treatment up with a natural shampoo cleansing and deep conditioner. This will assist with maintaining a healthy shine, as well as prevent breakage to my fragile ends.
Link on how to apply the oil and get the best effect:
http://www.wikihow.com/Apply-Amla-Oil
Here's a simple outline from Longing4length.com that lists the expected results from Alma:
Consider trying the Amla oil, and see if you notice the same positive results. Keep in mind that this oil is safe for all ages and all hair types. The only thing I'd suggest is to keep in mind is that the oil is very thick and greasy, so it can be heavy if you have thin or fine hair. Therefore, you would need to reduce the amount of oil you use, and possibly the length of time that you do the oil treatment. I have thicker and dryer hair, so a good saturation of Amla does my hair and scalp a huge favor!
Also, see link below that shares tidbits on other uses and pros of the Amla oil.
http://www.realbeautyspot.com/amla-miracle-oil-hair-growth/#_