I dont have any experience with steroids or growth hormones but i hope my answer will help you because i did much of research on topic of steroids,growth hormones (2years),proteins( 3 years ),creatine( 3 years),training (3 years),bulking,cutting ...
Mk-677 as i heard is helping you put on some lean muscle and lost some fat but it all depends on ur training and diet . I heard as well that Mk- 677 ( Nutrobal is other name for it).
Is expensive and injecting is daily is paniful ( this is what i heard from my friend and i found it 1-2 month before when i research about growth hormones and steroids ) .
Mk-677 has some side effects for guys who are prone to prolactin sides which is very small number of people using it . You will know if ur prone do prolactin if u alredy used some of ASS who have side effects of gynecomastia ( Trenbolone,Dbol just some that causes gynecomastia ) and if u got it from this kind of steroids that causes gynecomastia than u have higher chance if not 100 % u will be prone to prolactin sides.
Im medical cases Mk- 677 ( Nutrobal) is used for reducing tumorsin mice . ( LOWER dosages of Nutrobal is used at medical cases but very high dosages used in bodybuilding contest can have more harm than benefits , as well it all depens on product you use,how you use it,with what you use it,training and diet ) . I hope i helped you i achieved this information from friend personal experience using Mk- 677 and doing research .