Does metformin lead to low levels of vitamin D3 or vitamin b over time?

Vit B12 & others. In addition to depletion of vit b12, metformin has also been shown to deplete levels of Folic Acid and coq10 enzyme.
Low B12 possible. Metformin can cause the body to become depleted of vitamin b12. Often, an non-prescription supplement can correct this, but it is always a good idea to get a level checked to see if you need a supplement before you start taking one.
No and yes. Metformin does not lower vitamin d, but people with diabetes and people who are overweight are at increased risk if vitamin d deficiency. Metformin can cause b 12 deficiency.
Can lower b12. After several years on metformin, populations at risk of B12 deficiency such as the elderly (as they r more at risk for atrophic gastritis) might develop B12 deficiency- simple blood test to confirm. Easy to treat: B12 pills. Usu. Ppl on metformin get a lot more benefit from med than harm, even if they get B12 deficiency.