Plant protein powders can cast for an extremely long time, perhaps even as long as a couple of years.
Pea protein powder can last a very long time, possibly up to 2 years from manufacture if stored correctly.
Soy protein powder is designed to last, and last it does! In some cases soy protein powder can last for up to two years, if stored correctly.
Hemp protein powder lasts for a long time if stored correctly. For best results you need to store hemp protein powder away from light and moisture.