Is talcum powder the same as backing soda when you use it in the shower?

When you use backing soda and mix it with shampoo to get rid of greasy hair is is it the same alternative to use talcum powder with shampoo?Is talcum powder the same as backing soda when you use it in the shower?
Theoretically, either should absorb grease. Talcum powder won't hurt, but it is a finer powder and won't scrub so much on the scalp like the baking soda will. It also will wash away more easily because it is a lighter powder. It may not, overall, do as much good, but it can't hurt to try. If I remember right, talcum powder is very pasty when wet and not very gritty.