Adults with elevated fasting glucose/HbA1c (prediabetes or T2D) as adjuncts to lifestyle and medical care.
Form: berberine HCl
Dose: 500–1500 mg/day (in 2–3 divided doses)
With meals
12 weeks, then check labs
Why: Multiple RCT meta-analyses show reductions in HbA1c and fasting glucose vs placebo and additive effects with standard care.
Form: powder
Dose: 5–10 g before meals (2–3×/day)
10–15 minutes before meals with ≥250 ml water
8–12 weeks minimum
Why: GRADE-assessed meta-analyses show improvements in fasting glucose, HbA1c, and insulin sensitivity.
Dose: 15–25 g protein 15–30 min pre–high-carb meal
Notes: Blunts post-prandial glucose via gastric emptying and incretin effects.