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Head-to-head evidence comparison — which supplement is right for you?
Berberine vs Glucomannan: Berberine has the stronger overall evidence (7.5 vs 6.5/10); they're alternatives for metabolic health — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Berberine wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
8 of 8 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
7 of 8 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Berberine and Glucomannan have evidence — compare verdict strength side-by-side.
500mg 2-3x daily (1000-1500mg total)
With meals, Split into 2-3 doses
Berberine HCl capsules
1g three times daily before meals (3g total)
30-60 minutes before meals, With 1-2 glasses of water, Before largest meals for weight loss
Capsules (safest)
and 3 more not shown
4-12 weeks
8-12 weeks
First 2 weeks
If on diabetes medications
30-60 minutes
4-8 weeks
4-8 weeks
If improperly taken
Clinical Efficacy of Curcumin, Resveratrol, Silymarin, and Berberine on Cardio-Metabolic Risk Factors Among Patients With Type 2 Diabetes Mellitus: A Systemic Review and Bayesian Network Meta-Analysis
Phytotherapy research : PTR (2025) · Meta analysis · n=1337
For HbA1c, silymarin was more effective than resveratrol (MD -2.08, 95%Cl -3.50 to -0.72) (P < 0.05).
Effects of berberine and barberry on selected inflammatory biomarkers in adults: A systematic review and dose-response meta-analysis of randomized clinical trials
Phytotherapy research : PTR (2023) · Meta analysis · n=1600
In addition, the non-linear analysis showed a significant lowering effect of berberine/barberry on IL-6 and TNF-α levels in doses <1000 mg/day and less than 5 weeks of intervention.
Berberine Ursodeoxycholate for the Treatment of Type 2 Diabetes: A Randomized Clinical Trial
JAMA network open (2025) · Rct · n=113
The study included 113 patients with T2D (mean [SD] age, 54.3 [10.6] years; 72 male [63.7%]) who were randomized.
Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis
The American journal of clinical nutrition (2008) · Meta analysis · n=531
Meta-analysis of 14 randomised controlled trials with 531 participants.
The Impact of Glucomannan, Inulin, and Psyllium Supplementation (Soloways(TM)) on Weight Loss in Adults with FTO, LEP, LEPR, and MC4R Polymorphisms: A Randomized, Double-Blind, Placebo-Controlled Trial
Nutrients (2024) · Rct · n=112
The experimental group showed significant reductions in body weight (treatment difference: -4.9%; 95% CI: -6.9% to -2.9%; p < 0.01) and BMI (treatment difference: -1.4 kg/m2; 95% CI: -1.7 to -1.2; p < 0.01) compared to placebo.
Comparative effects of nutraceuticals on body weight in adults with overweight or obesity: A systematic review and network meta-analysis of 111 randomized clinical trials
Pharmacological research (2023) · Meta analysis · n=6171
We conducted random-effects network meta-analysis with a Frequentist framework to estimate mean difference [MD] and 95% confidence interval [CI] of the effect of nutraceuticals on weight loss.
The 1,000 mg point is a placebo-controlled trial of berberine 1.0 g daily for 3 months in 116 people with type 2 diabetes, where HbA1c fell from 7.5% to 6.6% and fasting glucose fell more than on placebo (PMID 18397984). The 1,500 mg point is two trials of 500 mg three times daily: one in 36 people with new type 2 diabetes where glucose fell with no significant difference from metformin in this small pilot, with transient stomach side effects in 34.5% (PMID 18442638), and a placebo-controlled pilot in 34 people with prediabetes where HbA1c fell from 6.40% to 5.43% (PMID 37679692). No trial compared doses, so the curve is flat between them and no optimal dose is set. Lower doses were not tested for glucose in any cited trial.
Two trials of glucomannan on its own report both a dose and a weight outcome. In a single-blind, placebo-controlled crossover of 20 adults with type 2 diabetes, 3 g a day for 4 weeks lowered BMI, a secondary result (PMID 18041436). In a randomised placebo-controlled trial of 53 overweight or moderately obese adults, 1.33 g before each of three meals (about 4 g a day) for 8 weeks did not change weight compared with placebo, and gastrointestinal symptoms, liver enzymes and creatinine did not differ from placebo (PMID 24490058). The curve stays flat at 4 g for that reason. No trial compared doses. The weight meta-analyses cited here do not state a dose, so they are not plotted.
AI-estimated from published studies. Interpret as directional guidance.
Berberine has a higher evidence score (7.5/10 vs 6.5/10) and wins in 2 of 3 categories.
For metabolic health, Berberine has a higher relevance score (95 vs 60).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
The honest tier list — proven staples vs situational vs mostly marketing. The hub the other guides feed into.
Which supplements clash with blood thinners, thyroid meds, antibiotics & more — and what to do.
What genuinely lowers LDL/triglycerides — and why "red yeast rice" is a statin in disguise.
Berberine, inositol, magnesium vs the cinnamon/chromium hype — and the med-interaction warning.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.