"There is certainly no data out there to suggest that giving growth hormone to an otherwise healthy person will make him or her live longer. We did find, however, that there was substantial potential for adverse side effects."

http://journal.frontiersin.org/Journal/10.3389/fgene.2012.00...

"In laboratory mice, mutations with the greatest, most consistent, and best documented positive impact on lifespan are those that disrupt growth hormone (GH) release or actions."