Research synthesisModerate evidenceModerate effect4 studies · 3 beneficial · 1 neutral · 0 harmful
Across 4 studies, 3 reported beneficial effects of turmeric on reducing hemoglobin A1c, with effect sizes ranging from small to moderate. The strongest evidence comes from a randomized controlled trial using 1500 mg/day for 365 days in adults with type 2 diabetes, which showed a small but statistically significant reduction in HbA1c (6.10% vs. 6.40%). Findings are consistent with meta-analytic data indicating a moderate reduction in HbA1c (e.g., MD = -0.31%), though one systematic review did not find turmeric significantly effective compared to other herbs.
- Effective dose range: 1500 mg/day
- Studied populations: Adults with type 2 diabetes mellitus (T2DM) or hyperglycemia, including those who are obese
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). The effect size varies across studies (small to moderate), and one large systematic review found turmeric not significantly effective in reducing HbA1c relative to other herbs, suggesting the benefit may be modest and inconsistent. Most evidence is derived from meta-analyses of heterogeneous studies, and the optimal dose and form remain unclear due to lack of form data in most studies.
Generated Jul 13, 2026