Gains>Hair. The more you exercise, the easier accepting hair loss becomes. I doubt whey protein/amino acids accelerates hair loss much. Just make sure you're using a clean product from a reputable company, and you should be fine. And before you think about substituting with plant protein, do some research. Lead and other heavy metals have been detected in many popular, plant protein brands. If I recall, I think it has something to do with the manufacturing process and/or the soil they use, but it's worth researching.