Low Human Growth Hormone Levels

I've had bloodwork done and among other things, low HGH levels are indicated. My regular doctor suggests intensity training to boost HGH, and my other doctor (Board Certified Anti-Aging Specialist who has helped considerably with Thyroid and other homonal replacement)suggests a two month series of HGH injections. I'm interested to try this treatment because he says that it should help repair "from the inside out" two tendon injuries that won't heal. Other benefits seem likely. Any downside?