Using protein powder after the expiration date is not recommended, as it may have decreased nutritional value or be contaminated with harmful bacteria or other harmful substances. Most protein powder has a shelf life of 1-2 years, but this can vary depending on the type of protein, storage conditions, and other factors.
It's important to check the expiration date on the packaging and discard any protein powder that has expired. If the powder has an off odor, clumps, or a noticeable change in color or texture, it's best to discard it and buy a new one. Additionally, proper storage of protein powder, such as keeping it in a cool, dry place, can help to extend its shelf life and ensure its quality and safety.