Protein powder itself is neutral in pH, meaning it is neither acidic nor alkaline. However, some ingredients added to protein powders can be acidic. For example, some types of protein powder contain citric acid as a flavoring or preservative, which is acidic. Additionally, the source of the protein can affect the pH of the powder. For example, animal-based protein sources, such as whey and casein, are naturally more acidic than plant-based protein sources, such as pea and rice.
It's important to keep in mind that the pH of the protein powder itself is not likely to have a significant impact on the overall pH balance of the body. The body has many mechanisms to regulate pH and maintain a healthy balance.