This does not constitute evidence that we should be supplementing with glycine, but I'm filing it under "an additional small reason to think that the glycine I take for sleep might not be so bad":
University of Tsukuba. "Scientists reverse aging in human cell lines and give theory of aging a new lease of life." ScienceDaily. www.sciencedaily.com/releases/2015/05/150526085138.htm (accessed May 27, 2015).
(http://www.sciencedaily.com/releases/2015/05/150526085138.htm)
But mostly, it's just a really cool finding!
Brian
P.S. Full text of research report:
http://www.nature.com/srep/2015/150522/srep10434/full/srep10434.html