Research synthesisModerate evidenceSmall effect4 studies · 4 beneficial · 0 neutral · 0 harmful
Across 4 studies (all meta-analyses or observational), black cumin (Nigella sativa) supplementation consistently showed small beneficial effects on diastolic blood pressure, with all findings statistically significant. The most-studied dose range is 200–4600 mg/day, and effects were observed in metabolic disease patients and postmenopausal women with hypertension. Median study duration was 32 days (about 4.6 weeks), so benefits appear within a few weeks.
- Effective dose range: 200-4600 mg/day
- Studied populations: patients with metabolic diseases, postmenopausal women with hypertension
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 is small (average ~2.7 mmHg reduction), which is modest on an individual level though potentially meaningful at population scale. Most trials were short-term (median 32 days); long-term efficacy and safety are unknown. No specific supplement form (e.g., oil, seed powder) was consistently reported, so results may not apply equally to all black cumin products.
Generated Jul 4, 2026