IGF is a growth hormone. Growth hormones are produced by animals and are especially found in mammal milk because they help the baby grow. There is no growth hormone in soya, but protein per se triggers growth. Soy protein isolate is a part of soy. Since we are always talking about whole plant-based foods, we are not interested in isolated parts of substances and should not eat them. Soy protein isolate is the isolated soy protein without the carbohydrate, but we do not need this. The best rule – never eat it if you don’t know what it is, or cannot pronounce it or understand it.