I started taking the 5,000 iu dissolve under you tongue tablets and within only 2 hours there was a literal jolt of normalcy not experienced in several years.
Vitamin B12 is a miracle!!!. B12 quite literally changed my life. It took me back to normalcy not experienced in many years.
B12 can be problematic depending on your genes. . Comt, vdr taq, mthfr, etc . If you have a methylation problem etc.
B12 issue can be hard to diagnose in US because they use to low of a level and other issues.
This article helps to understand.
Many people have the mthfr issue but just don’t know it
https://pmc.ncbi.nlm.nih.gov/articles/PMC6543499/