Research synthesisLow evidenceSmall effect4 studies · 2 beneficial · 2 neutral · 0 harmful
Across 4 studies on black cumin (Nigella sativa) supplementation for reducing postprandial glucose, 2 reported beneficial effects of moderate-to-small size, while 2 found no significant benefit (neutral). The aggregate finding is mixed, with a predominant small effect size. The most robust evidence comes from a large 2025 meta-analysis (82 RCTs, 5026 participants) showing moderate beneficial effects at doses of 200 to 4600 mg/day, though two other meta-analyses/systematic reviews and one small RCT show neutral or small beneficial results. Median study duration was 60 days, but findings are not uniform across populations.
- Effective dose range: 200 to 4600 mg/day
- Studied populations: type 2 diabetes patients, general adult population (meta-analysis), adolescent girls with PCOS
Caveats: Evidence base is small (only 4 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The largest study (meta-analysis) shows moderate benefit, but two other meta-analyses/systematic reviews show neutral or small effects, indicating inconsistency. One small RCT in adolescents with PCOS found no significant interaction effect. The wide dose range (200–4600 mg/day) and varying study populations limit precision of recommendations.
Generated Jun 10, 2026