Metformin as a Geroprotector (2011)
ncbi.nlm.nih.gov
ncbi.nlm.nih.gov
For the all over the map and not all that impressive nature of metformin data, take a look at the table in this open access paper:
http://impactaging.com/papers/v4/n5/full/100455.html
The reason why metformin is getting attention now is because a coalition of researchers are using it as the narrow end of the wedge to change the FDA position on treatment of aging, which is currently that aging is not a medical condition and thus no-one is permitted to treat it. They cannot possibly expect meaningful results on aging, but that's not the point; the point is to run a trial with something that the FDA cannot object to on other grounds because it has been used for decades and is already approved for other uses. Thus the FDA accepts a trial to slow aging, and the door is open to all the methods that might actually have some meaningful effect in the future.
http://news.sciencemag.org/biology/2015/09/feature-man-who-w...
Calorie restriction support was recently undermined by a NIA study. The conflict between the NIA and Wisconsin study is summarized by TIME here: http://healthland.time.com/2012/08/29/want-to-live-longer-do...
The teams are supposed to be working on a joint study to resolve their differing results.
EDIT: I have seen Dr. Mosley's BBC documentaries and they pre-date the recent CRON results. His HIIT segment is also very interesting. Not dismissing any of it - just not the slam-dunk that it seemed at first.
On BBC Michael Mosley has some interesting segments about CRON and its help reducing the levels of the IGF-1 hormone.
In my wife's case, it was nausea and hypoglycemia.
If she was prescribed 1g tablets, for example, have her ask for a new script for twice as many 500mg tablets. (Those 1g are a pain to split.)