I'm not an expert but here's my understanding. The liver needs insulin present for igf-1 conversion. Taking it 30 minutes or so pre meal with carbs gives your liver the insulin spike it needs. This is why it's important to watch your blood glucose levels. Your body will need to produce more insulin since some will be canceled out for igf-1 conversion. You get short term insulin resistance but your body adapts. Over the long term if you're using large amounts of gh insulin resistance drifts up. Just something you need to watch by tracking blood glucose levels fasted and an hour post meal.