157 is definitely one of the better peptides. It does make sense that it brings additional blood into the area as that is a major factor in healing. It does have it's limits such as not being able to heal an injury that really req. surgery. It can def. help speed up the healing process. I had a tendon repair surgery and after 3 yrs. it was still not 100%, maybe 75%. Within 2-3 months of using it my shoulder is now 100% but of course then the rt. shoulder is now in pain due mostly to arthritis. I did see my shoulder guy and there are no tendon issues so I'll be attacking this one with cortisone shots and 157. I also use heat cream in both shoulders prior to working out and that seems to help. My shoulders do get red after applying so I'm thinking it does bring blood into the area.