Best Supplements for Reduced Body Mass Index
Ranked by research evidence. Compare 111 supplements across 155 papers from the biomedical literature, with effect direction, evidence strength, and dose range for each.
Top picks by evidence
- Moderate evidence6 studies
Across 6 studies (4 beneficial, 2 neutral), turmeric/curcumin shows predominantly small beneficial effects on reducing body mass index (BMI). The most robust evidence comes from a network meta-analysis in type 2 diabetes (moderate effect) and an RCT in women with severe obesity (small effect). Two meta-analyses in nonalcoholic fatty liver disease and broader T2DM populations found no significant effect, indicating that benefits may be population-specific. The median study duration was 91 days, but only one study reported this detail.
- Moderate evidence6 studies
Across 6 studies (4 meta-analyses, 1 systematic review, 1 review), 4 reported a beneficial small effect of L-carnitine on reducing body mass index, while 2 found no significant effect. The most studied dose range was 1–2 g/day, and effects were typically observed in clinical populations (e.g., type 2 diabetes, overweight/obesity) over a median duration of 56 days (8 weeks). The predominant effect size is small, with one study reporting a moderate effect.
Dose: 1–2 g/day - Moderate evidence5 studies
Across 5 studies, 3 reported beneficial effects of black cumin (Nigella sativa) on body mass index, with a predominantly small effect size. Two meta-analyses (n=2,145 and n=5,026) found statistically significant but modest reductions in BMI (e.g., -0.51 kg/m²), while one observational study also showed benefit. The median study duration was 56 days, suggesting effects are typically observed at 8 weeks or more.
Dose: 200 to 4600 mg/day
- ModerateTurmericAcross 6 studies (4 beneficial, 2 neutral), turmeric/curcumin shows predominantly small beneficial effects on reducing body mass index (BMI). The most robust evidence comes from a network meta-analysis in type 2 diabetes (moderate effect) and an RCT in women with severe obesity (small effect). Two meta-analyses in nonalcoholic fatty liver disease and broader T2DM populations found no significant effect, indicating that benefits may be population-specific. The median study duration was 91 days, but only one study reported this detail.4 beneficial2 neutral6 studies
- ModerateL-CarnitineAcross 6 studies (4 meta-analyses, 1 systematic review, 1 review), 4 reported a beneficial small effect of L-carnitine on reducing body mass index, while 2 found no significant effect. The most studied dose range was 1–2 g/day, and effects were typically observed in clinical populations (e.g., type 2 diabetes, overweight/obesity) over a median duration of 56 days (8 weeks). The predominant effect size is small, with one study reporting a moderate effect. · Dose: 1–2 g/day4 beneficial2 neutral6 studies
- ModerateBlack CuminAcross 5 studies, 3 reported beneficial effects of black cumin (Nigella sativa) on body mass index, with a predominantly small effect size. Two meta-analyses (n=2,145 and n=5,026) found statistically significant but modest reductions in BMI (e.g., -0.51 kg/m²), while one observational study also showed benefit. The median study duration was 56 days, suggesting effects are typically observed at 8 weeks or more. · Dose: 200 to 4600 mg/day3 beneficial2 neutral5 studies
- Moderategreen teaAcross 4 meta-analyses, 3 reported statistically significant beneficial effects of green tea on reducing body mass index (BMI), with effect sizes ranging from small to large. The predominant effect direction is beneficial, with a moderate-to-mixed effect size (small to large across studies). The most common population studied was overweight or obese adults, and effects were typically small to moderate in magnitude, though one meta-analysis reported a large effect (SMD: -1.2).3 beneficial1 neutral4 studies
- ModerateSpirulinaAcross 3 studies, all reported beneficial effects of spirulina on reducing body mass index (BMI), with effect sizes ranging from small to moderate. The most recent meta-analysis (2025) found a statistically significant moderate reduction (WMD: -0.58 kg/m², P=0.001). Evidence is strongest in adults with metabolic syndrome, though dose ranges were inconsistently reported (20 mg to 6 g daily).3 beneficial3 studies
- LowBerberineAcross 4 studies, 2 reported small beneficial effects on body mass index (BMI), while 2 found no significant difference. The median study duration was 12 weeks, and typical doses ranged from 500 mg twice daily to 1200 mg/day. Populations studied included clinical groups with hyperlipidemia, type 2 diabetes, or obesity. · Dose: 500-1200 mg/day (typically 500 mg twice daily)2 beneficial2 neutral4 studies
- LowVitamin DAcross 9 studies, 1 reported a beneficial moderate-sized effect on reduced BMI, while 8 reported neutral small effects. The predominant effect direction is neutral with a small effect size. Most studies were in clinical populations (e.g., women with PCOS, people with depression, obese children) and doses varied or were not specified; median study duration was 84 days.1 beneficial8 neutral9 studies
- Very lowflaxseedAcross 3 studies on flaxseed for reduced body mass index, 1 reported a beneficial small effect, while 2 found neutral small effects. The only statistically significant finding comes from a review (not a controlled trial), and the highest-quality evidence (two meta-analyses) found no significant benefit in diabetic or coronary artery disease populations. Evidence is too limited to identify a consistent effective dose, form, or population.1 beneficial2 neutral3 studies