Evidence explainerMetabolic Health & Blood Sugar

Blood Sugar Supplements vs Placebo: Berberine, Psyllium and Chromium

Berberine, psyllium and chromium lowered glucose in trials of people with type 2 diabetes. In people with normal glucose the effects shrink or vanish, and some blood sugar products have contained hidden drugs.

By Kymata Health editorial teamPublished October 10, 2026Last verified October 10, 2026

Medical review pending. Written by our editorial team from the studies and documents cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • Berberine 1 g/day for 3 months lowered HbA1c from 7.5% to 6.6% in 116 people with type 2 diabetes and high lipids, vs placebo [1].
  • Across 19 trials, psyllium lowered fasting glucose by about 7 mg/dL and HbA1c by 0.75 points vs placebo [2]; an earlier analysis found no significant lowering in people with normal glucose [3].
  • Chromium lowered HbA1c by 0.71 points in type 2 diabetes trials, with extreme heterogeneity [4], and showed no effect on glucose or insulin in people without diabetes [5].
  • The FDA found undeclared metformin and glyburide in a product sold as blood sugar support [6].

Berberine

In a randomized trial of 116 people with type 2 diabetes and dyslipidemia, berberine 1 g/day for 3 months lowered fasting glucose, HbA1c (7.5% to 6.6%), triglycerides and LDL cholesterol significantly more than placebo [1].

Berberine interacts with several medicines; see our berberine interactions guide and our check of the "nature's Ozempic" claim.

Psyllium

A 2024 meta-analysis of 19 randomized trials (962 participants) found psyllium lowered fasting glucose (-6.89 mg/dL), HbA1c (-0.75) and HOMA-IR, but not insulin [2].

A 2015 meta-analysis found the effect tracked starting glucose: significant improvements in type 2 diabetes, a modest effect in people at risk, and no significant lowering in people with normal glucose [3]. See the psyllium monograph.

Chromium

A 2020 meta-analysis of trials in type 2 diabetes reported lower fasting glucose (-19 mg/dL) and HbA1c (-0.71), but heterogeneity for fasting glucose was extreme (I² 99.8%) [4]. An earlier meta-analysis found no association between chromium and glucose or insulin in people without diabetes [5].

Hidden drugs and real treatment

In December 2024 the FDA told consumers not to use Fouzee SugarLin Herbal Formula after finding undeclared metformin and glyburide, which can cause dangerous low blood sugar [6]. A supplement that works suspiciously well is a red flag.

If you have diabetes, do not swap prescribed treatment for a supplement. For prediabetes, see our lifestyle vs metformin guide.

Quick answers

Can I take berberine with metformin?

Both lower glucose, and repeated berberine dosing inhibited several drug-metabolizing CYP450 enzymes in a human study [7]. Ask your clinician first; our interactions guide covers the details.

More in Metabolic Health & Blood Sugar

References

  1. [1]Treatment of type 2 diabetes and dyslipidemia with the natural plant alkaloid berberine. J Clin Endocrinol Metab, 2008. PMID 18397984
  2. [2]The effect of psyllium on fasting blood sugar, HbA1c, HOMA IR, and insulin control: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials. BMC Endocr Disord, 2024. PMID 38844885
  3. [3]Psyllium fiber improves glycemic control proportional to loss of glycemic control: a meta-analysis of data in euglycemic subjects, patients at risk of type 2 diabetes mellitus, and patients being treated for type 2 diabetes mellitus. Am J Clin Nutr, 2015. PMID 26561625
  4. [4]Effects of chromium supplementation on glycemic control in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials. Pharmacol Res, 2020. PMID 32730903
  5. [5]Glucose and insulin responses to dietary chromium supplements: a meta-analysis. Am J Clin Nutr, 2002. PMID 12081828
  6. [6]Fouzee SugarLin Herbal Formula may be harmful due to hidden drug ingredients. U.S. Food and Drug Administration, 2024.
  7. [7]Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol, 2012. PMID 21870106

Dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Prescription options need a licensed clinician. Talk to your clinician or pharmacist before starting anything new, especially if you take prescription medicines, are pregnant or breastfeeding.

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