There are both long and short esters is sus. It was made for hrt so a person would only need on amp every three weeks. This is to get blood levels to a normal level. If you are using it for building muscle, who isn't, doing and amp twice a week is fine. If you want 500 mg test per week. In my opinion every other day is to much. When I am on I do an amp every m,w,f for 750 a week. This works for me as well as countless others.