First most IGF-1 out there is fake. When you get the real deal you will know. So get a good source is number one. Second use greater amounts while on cycle 30-50mcg, off cycle only do 10-20mcg.
Why: IGF-1 makes everything grow. While on cycle your muscles are growing, so it enhances that. While off cycle you want to use the IGF-1 to keep your muscle, and regenerate your own bodies chemistry. During the off-cycle time you gain more fat. If your body is in a fat building mode, could IGF-1 actually target growth in the fat cells also. Yes in my opinion, so use less in the off-cycle.