Does baking powder have aluminum in it and what are the ingredients in baking powder?

Some baking powders do contain aluminum, specifically in the form of sodium aluminum sulfate. However, many brands offer aluminum-free baking powder, which typically contains just an acid (like cream of tartar) and a base (like baking soda). The main ingredients in baking powder are usually a combination of an acid, a base, and a filler, such as cornstarch, to keep the ingredients dry and prevent clumping. Always check the label to determine if a specific product contains aluminum.