Supplements and metformin.
Metformin is the first-line oral diabetes drug and the most-cited example of medication-induced nutrient depletion. After a year or more of daily use, vitamin B12 levels fall in roughly 10 to 30 per cent of patients. Annual B12 monitoring is sensible; supplementation is straightforward if needed.
Several supplements have their own glucose-lowering effect and stack additively with metformin: berberine, alpha-lipoic acid, inositol, chromium, and bitter melon all have evidence here. Adding any of these without monitoring fasting glucose carries hypoglycaemia risk. None of them are excluded; they are pairs where home glucose monitoring at the start makes sense.
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