I am using ostrovit gh booster, i bought this off ebay, it's in a white, purple and green tub and is a powder. i was wondering if this is safe?

Doubtful.: I'd be curious at least about any medications, supplements or even foods purchased off eBay. That's not to say that there aren't credible vendors there, but where's the documentation of quality assurance? Where's the prevention of tampering? Where's the standardization of the product? I can't vouch for the safety of such a purchase.