What to take for blood sugar
Graded by the strength of the evidence — strongest first. Nothing here is sold to you.
Omega-3grade B— Meta-analysis in type 2 diabetes: results for omega-3 on glucose control were mixed and, overall, no consistent improvement in glycemic control was demonstrated. The authors note the EPA/DHA ratio and early intervention may modify effects — a subgroup signal, not a general glucose benefit.
Magnesiumgrade C— modest improvement in insulin sensitivity / fasting glucose, mainly in deficiency or diabetes
Ashwagandhagrade C— Systematic review and meta-analysis of Withania somnifera (ashwagandha) in diabetes: pooled data suggest a possible glucose-lowering effect, but the authors conclude the anti-diabetic profile is not yet established and call for larger, longer randomized trials measuring blood glucose, HbA1c and insulin. Signal, not confirmation.
Creatinegrade C— Systematic review and meta-analysis (9 studies): creatine supplementation had no significant overall effect on fasting blood glucose or insulin resistance. Some benefit appeared in the small number of studies in people with diabetes, so any effect is likely context-specific rather than general.
Ginkgograde C— Meta-analysis: Ginkgo biloba extract significantly reduced fasting blood glucose and improved insulin resistance (HOMA-IR) versus control, plus reduced BMI and waist circumference, but did NOT significantly change HbA1c or fasting insulin levels — a partial biomarker signal, not comprehensive glycemic control.
Melatoningrade C— Meta-analysis of 12 RCTs: melatonin supplementation significantly reduced fasting glucose and improved insulin sensitivity (QUICKI index), but had no significant effect on insulin levels, HOMA-IR, or HbA1c. A partial biomarker signal on fasting glucose specifically, not comprehensive glycemic control.
Vitamin Dstudied, no effect— Large randomized trial (D2d ancillary analysis) in older US adults: vitamin D supplementation did NOT significantly reduce incidence of type 2 diabetes in this trial alone. When pooled with prior trials in meta-analysis, a modest reduction was observed — so the evidence is suggestive at the pooled level but the single largest trial itself was a null result.
Glucosaminesafety-flagged— Systematic review (11 studies, 6 RCTs): several studies found DECREASED insulin sensitivity or increased fasting glucose in people taking glucosamine, particularly those with baseline impaired glucose tolerance or insulin resistance. This is a caution signal, not a benefit — people with pre-diabetes or diabetes should be aware glucosamine may worsen glucose metabolism in some studies.
NMNstudied, no effect— Review of 8 human RCTs (342 mainly non-diabetic middle-age/older adults, 14 days to 12 weeks, 250-2000 mg/day): NMN supplementation showed no significant benefit on fasting glucose, fasting insulin, HbA1c, insulin resistance (HOMA-IR), or lipid profile. Short-term NMN supplementation did not meaningfully improve glucose control in this population.