Yes, but why? Are you trying to save money on HGH? A lot of the benefits of HGH is IGF increases and spend some time looking up the different numbers my reputable people who took generic, script HGH and MK677. It is very surprising. All that being said, I find MK677 is nothing compared to script HGH. Not to say you should do this but I know many people who take HGH (script) 5 days a week and then MK677 the two days they don't.
Keep in mind MK677 is still experimental and no one knows the side effects long term hence the reason people cycle it - 10 days on / 10 off or whatever protocol you choose. There are supplements to take with MK677 to help but I would have to look it up again since I no longer use it.
The most impressive effects of MK677 was it made me extremely calm even when the other side of my is going to come out and it stopped hair loss. IGF and hair loss is related - look it up and there is logic behind it.
If it was me I would not take both on the same day, I would wait until your HGH runs out and then use the MK but it won't counteract the HGH.