Where can I get hair thickening shampoo; not hair loss treatment shampoo?

I’m looking for a good shampoo that will make my hair more voluminous and thicken the hairs that are in my head already. I’m not looking for any shampoos that contain hair-loss inhibiting or hair regrowth drugs… just something that will make the hair thicker and stronger.

Anyone have suggestions?
Thanks for the tips, Miissa. However, everything I’ve seen says that henna will also color your hair. I don’t want this.