Can Soy Protein Powder cause diarrhea?

Unfortunately diarrhea can be a side effect of soy protein powder if you are soy intolerant. Diarrhea due to soy intolerance should not last for more than a day, once any ingested soy has left your system. If you find you suffer from diarrhea after taking soy protein powder, we recommend you try an alternative source for your protein powder.