It depends. First, you certainly don't NEED one, but they CAN help. Protein is a complex thing, anyone saying otherwise is lying or ignorant. You certainly need a "complete" protein source, meaning it has all the Amino Acids your body requires. You could just add chicken/eggs/soybeans to your diet and get mostly the same effect. Whey protein is technically more "bio-available" meaning your body can use it more efficiently. Its not a huge difference. You can also by pure Whey as a baking ingredient for a lot cheaper.

If you mean prework-outs, that gets even iffier. Some are just sugar, which you likely don't want. Some have vasodialators like Arginine or its superior brother Citrulline. These convert into Nitric Oxide in your body, which causes blood vessels to expand and get more blood to muscles. Some have Beta-Alanine which works but may make you unbearably itchy. The best prework-outs are coffee or beet juice. Beets for their vasodilation. Coffee not just for the caffeine, but coffee specifically reduces muscle soreness. Seriously, drink it before/after exercise, it helps a ton. While we're on the subject, Magnesium Glycinate can help with recovery a lot. (Magnesium Oxide does nothing but it is a laxative, lmao)