Go for whey, soy increases your estrogen level and they are not as complete as whey protein. The difference between the two is that whey comes from milk and soy comes from soy beans.
i think that statement is 50% true and 50% false
few studies have shown increase in estrogen levels by taking soy but many studies shows no effect in estrogen levels
there is no right conclusion for this
but soy is a cheap source of protein , if you wanna consume soy source it would be better to go with 100% soy protein supplements over normal soy beans as too much soy beans leads to body heat and gas problems ( you may fart more lol )
