You won't gain mass with peptides or HGH, they will lean you out and make your body look better though. You will gain size with MK677 but it will be water weight, it will definitely will make you bigger from the bloat while you're on it if that is all you are looking for.
Just my personal experiences....
Also if you have the option to use real GH why would you choose peptides instead? IGF belongs on it's own from peptides and GH in my opinion, I use that when I'm trying to peak for a vacation or something like that. I don't think it leads to any permanent or even long lasting gains but fuck do you look good while on it!