Supplements for glucose control work best as adjuncts to diet, not substitutes for medical care. Several ingredients have meaningful RCT data for insulin sensitivity and postprandial glucose.
- Berberine (500 mg, 2β3x/day with meals): One of the most potent natural glucose-lowering compounds. Multiple meta-analyses show HbA1c reductions comparable to metformin in some trials.
- Alpha-lipoic acid (300β600 mg/day): Improves insulin sensitivity and is used clinically in Europe for diabetic neuropathy.
- Chromium picolinate (200β1000 mcg/day): Modest improvement in insulin sensitivity, particularly in prediabetic populations.
- Cinnamon (ceylon, 1β6 g/day): Meta-analyses show small fasting glucose reductions (-8 to -15 mg/dL).
- Magnesium (200β400 mg elemental): Deficiency impairs insulin signaling. Glycinate or citrate forms preferred.
- Products claiming to "reverse diabetes" β false and dangerous
- Products replacing prescribed antidiabetic medications
- Cassia cinnamon at high doses (coumarin liver risk)
- Proprietary "diabetic support" blends with hidden chromium doses
Evidence hierarchy (berberine > ALA > chromium), dose vs. RCT protocol, form (ceylon cinnamon over cassia), and safety for combination with metformin or insulin. Products overstating effects score lower.