There is evidence that selenium repletion is beneficial for Graves disease, while high levels of selenium and long-term supplementation have been associated with increased risk of type 2 diabetes
7 On the other hand, vitamin B12 given via injection will give you the maximum benefit because it bypasses the digestive system and goes directly to your bloodstream
Chen XN, Moustafa GA, Lee J-J, Seidl S, Steliou K, Lu L, et al
Female C57BL6/J dam at 3-4 months received daily intraperitoneal injections between embryonic days 16.5 and 18.5
J Nat Sci Biol Med 4(2):336340 Gunasekara P, Hettiarachchi M, Liyanage C, Lekamwasam S (2011) Effects of zinc and multimineral vitamin supplementation on glycemic and lipid control in adult diabetes