Gleser MG et al
This can range from a bit of itching and red bumps to more serious stuff like swelling and trouble breathing
Kunwar A, Bag PP, Chattopadhyay S et al (2011) Anti-apoptotic, anti-inflammatory, and immunomodulatory activities of 3,3-diselenodipropionic acid in mice exposed to whole body -radiation
I don't see how you are getting that only 5mcg is lost daily: if you have injected say 1000 mcg of B12, most of it is peed out within a few days
Bellinghieri G, Santoro D, Calvani M, Mallamace A, Savica V: Carnitine and hemodialysis
Pu A-Y, Huang Y-L, Pu C-M, Kang Y-N, Hoang KD, Chen K-H, et al