Yeah, I have heard a month as well, but I've also heard a week, and sometimes I see ten days thrown around. I don't know the hard science, which is why I qualified what I said with "personally" as I didn't want to make it sound like I was making a definitively factual statement, but rather stating my preference. While not a fortune any more, GH is still one of the more expensive things I take, especially when you take frequency (daily) and time frame (indefinite use) into account, so I'm being more cautious as I don't want to risk wasting a portion of that money by injected degraded or inert GH.