What is whey protein powder made of?
                                
                                
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                                    3 min read                                
                            
                                Over 80% of milk's protein content is casein, leaving the remaining 20% as the liquid portion known as whey. This once-discarded liquid is now a prized supplement. But **what is whey protein powder made of?** At its core, it's a byproduct of cheese production, which undergoes significant processing to transform into the popular powder found on store shelves.