Is metformin a blood thinner?

No it's not. It's used to lower blood sugar in people with diabetes. Take care! http://www.Drugs.Com/metformin.Html.
"Thinner"=Misleading. Blood viscosity=primarily due to surface adhesiveness of red blood cells. Blood viscosity is ?ed in anemia (RBCs farther apart), but is not healthy. All the agents commonly referred to as "thinners" either inhibit blood clotting or stimulate blood clot destruction proteins. Thus all=anti-clotting agents (do not reduce blood viscosity), are recommended to ? clots inside blood vessels & ? bleeding.