it may not just be baking soda if it has baking soda baking powder salt and all-purpose flour in it that is just like using self rising flour sometimes it does not have to have baking powder in it for you to improvise self rising flour instead.
You do if you want them to rise properly.
when using a self rising mix not much , when using a plain mix the muffins wont "rise"
Baking soda will cause things to rise also. Muffins are smaller so there is not as much need for lift. Baking powder will give more rise than soda. Whoever created the recipe chose to use soda instead of baking powder.
Yes, self-raising flour will help make the muffins rise, while plain flour won't unless you add baking powder to the muffins.
Muffins are a type of "quick bread," which uses baking powder or baking soda as leavening. Yeast requires an hour or more to raise dough or batter, and produces a different crumb than desired in (American) muffins.
Bananas are not the best leavening agent for muffins. Baking powder is the best leavening agent for baking. Bananas do not rise to the same degree as baking powder.
The key factor that determines the rising of muffins is the chemical reaction between baking powder and liquid ingredients, which creates carbon dioxide gas bubbles that make the muffins rise.
baking powder
Baking powder in a recipe helps your item rise when baking.
baking powder helps the cupcakes to rise
Baking soda does not rise as well as baking powder
helps it rise? :)