true enanthate's half life is 10-10.5 days, but if u injected only once a week, your blood levels would go up, then go down, the back up when u receive the next shot, and so on.......so it would be wise to take it, say on a monday and thursday, so you keep your blood levels as even as possible......u can in fact just do it once a week if u want, but it would be more benificial to do it twice a weekOriginally Posted by Pork Chop