According to reliable sources, vitamins: D, C, and B7 have the effect of lowering blood sugar. Vitamin D: Vitamin D improves the function of pancreatic cells that make insulin and reduces insulin resistance. Therefore, it has the effect of regulating blood sugar levels, helping to control type 1 and type 2 diabetes. Vitamin C: Taking vitamin C supplements may help lower high blood sugar and control blood pressure throughout the day in people with type 2 diabetes. Taking 500 mg of vitamin C twice daily lowers blood sugar throughout the day and minimizes spikes in blood sugar after meals. Vitamin B7: A type of vitamin B7 called Biotin works to lower blood sugar. Biotin improves glucose tolerance and improves insulin resistance. When biotin is combined with chromium, the blood sugar-lowering effect is even stronger. Biotin can be used as an adjunct to current insulin therapy. It is helpful in controlling blood sugar and lowering lipid levels in diabetic patients. This helps to control diabetes without any side effects.