it's ok to inject one a week.
it's just BETTER to inject every 3.5 days
the half life of test e is 10.5 days, so....
one week=7days half week=3.5days
7 + 3.5 = 10.5
in other words it keeps your blood levels more constant so sides are minimal.
i've done both ways and there is not that big of a difference. i got a little acne.
i prefer 2x per week though.