For the most part, injectable primo is methenolone enanthate, but the primo in primo tabs is methenolone acetate. There are some underground labs making injectable "primo" out of the acetate version though. But like SofaGeorge said, doses need to be ridiculously high, and even then the results aren't very good. At that point you're just pissing away your money, and at the same price you could be running a nice dose of anavar instead.
If you're going to use primo, find a LEGIT supply and INJECT it. If you want a 'safe' oral, just go with anavar.