Gh, ghrp,cjc ect are mainly to increase gh production. Of course your igf1 levels go through the roof as a result of administering gh or a gh releasing hormone but administering igf1 seperataly and directly will be the most effective way of increasing the systematic igf1 levels. Gh and igf1 are synergistic together and work well in conjunction with each other. Its not all done to result in an increase of igf1 levels only. Gh has other benetfits than increasing your igf1.