Yes, primo enanthate can be injected once per week. However, the only forms of it I am familiar with that are in mexico (assuming they are legit, which would be a near miracle unless you know somebody) are like 50mg/ml. So, to get a decent dose, would require you to inject 6-8ml of oil into yourself. Not to mention, you can still get busted for possessing steroids without a script in mexico.
go domestic