Protein supplements vary in types, including whey, casein, soy, and pea. Whey protein is popular for its rapid absorption, making it ideal for post-workout recovery. Casein digests more slowly, beneficial for overnight muscle repair. Soy protein is a complete plant-based source, suitable for vegetarians, while pea protein offers a good alternative that's hypoallergenic. Each type varies in amino acid content and absorption rates, catering to different fitness goals, dietary needs, and lifestyle choices.