MK677 is doesn't play with hormones as it's just a ghrelin mimetic. It will cause the body to release more of it's own growth hormone. However this doesn't come without it's own side effects which include intense bloating, insulin resistance, insatiable hunger and lethargy.

There are peptides that give the same/if not better benefits but with almost no side effects. GHRH'S and GHRP'S will do this. The peptides are far superior. The only thing that MK has over the injectable peptides is the fact that can be taken orally.

Ostarine is very good for muscle and tendon recovery but it just depends on the route you want to take. Do you want to start playing with hormones? I would advise you to check out the peptide subreddit and give the guide a read as I think what you may be looking for is there.