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Best Supplements for Blood Sugar and Insulin Resistance in 2026

Supplements for diabetes, blood sugar and insulin resistance ranked by evidence, from berberine and inositol to psyllium, cinnamon, alpha-lipoic acid and chromium, with in-stock picks for each need.

Published

November 7, 2026

Read time

13 min read

Medically reviewed by

Rhonda Collins, FNP-C

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Quick Summary

The best supplements for blood sugar and insulin resistance are berberine and inositol, followed by soluble fiber. In people with type 2 diabetes, a meta-analysis of 46 trials found berberine, alone or added to standard care, lowered HbA1c by about 0.7 percentage points ^[1]. Myo-inositol lowered fasting insulin and HOMA-IR in women with PCOS ^[2]. Psyllium fiber lowered fasting glucose and HbA1c in people being treated for type 2 diabetes, and had little effect when glucose was normal ^[3]. Cinnamon, chromium, alpha-lipoic acid and magnesium have weaker or mixed evidence ^[4]. No supplement replaces diabetes medication, and several of these add to its glucose-lowering effect. The most useful first step is an HbA1c, fasting glucose and fasting insulin test.

Introduction

“Are there supplements for diabetes and blood sugar that actually work?”

A few have real trial evidence behind them, most have very little, and none replaces the basics. The National Center for Complementary and Integrative Health (NCCIH) summarizes it this way: some studies suggest chromium, cinnamon or berberine might help with blood sugar control, but most of those studies are small and differ in dose, formulation and population ^[4]. For most supplements sold for diabetes, there is no evidence of benefit ^[4].

This guide is organized by need rather than by product. Each section names the situation where a supplement has evidence, what that evidence found and in whom, and which blood test tells you whether it applies to you. It covers prediabetes, insulin resistance and type 2 diabetes. It does not cover type 1 diabetes, where insulin is required.

What makes a good blood sugar supplement:

• A single, named ingredient at an amount you can compare with the studies
• The form the trials used (berberine HCl, myo-inositol, psyllium husk, alpha-lipoic acid)
• Third-party testing or a GMP-certified facility
• A label that lists interactions and pregnancy warnings rather than hiding them

What to avoid:

• “Glucose support” blends that do not list each ingredient’s amount
• Products that claim to cure diabetes or replace your medication, which the FDA treats as illegally marketed ^[4]
• Stacking several glucose-lowering supplements at once, especially alongside diabetes medication
• Starting a supplement without a baseline HbA1c to compare against

Which Supplement Fits Your Blood Sugar Goal?

Top picks

Reviews

Each card shows the current price from the Mito catalog.

Best for Lowering HbA1c and Fasting Glucose: Berberine

Berberine is a plant compound found in barberry, goldenseal and related herbs. A 2021 meta-analysis of 46 randomized trials in people with type 2 diabetes found that berberine, alone or added to standard diabetes treatment, lowered HbA1c by an average of 0.73 percentage points, fasting glucose by 0.86 mmol/L (about 15 mg/dL), and fasting insulin and HOMA-IR compared with control groups ^[1]. NCCIH notes the limits of that evidence: most trials were in Chinese patients, results varied widely, and some studies were of poor quality ^[4]. Berberine has not been shown to replace diabetes medication.

Berberine also behaves like a drug in one important way. In healthy men, two weeks of berberine slowed three liver enzymes (CYP2D6, CYP2C9 and CYP3A4) that clear many prescription medicines ^[5]. Common side effects include nausea, diarrhea, bloating and constipation, and NCCIH advises against berberine during pregnancy and breastfeeding ^[4]. If you take glucose-lowering medication, adding berberine also raises the risk of low blood sugar. For more on how berberine compares with lifestyle changes, see how to improve insulin sensitivity.

Best for Berberine HCl plus phytosome, third-party tested

1. Thorne Berberine

• Form: Berberine HCl plus berberine phytosome (Indian barberry root)
• Berberine per Serving: 450 mg berberine HCl and 550 mg berberine phytosome
• Label Serving: 2 capsules, with food
• Third-Party Testing: Label states it is third-party tested and certified
• Bottle: 60 capsules (30 servings)
• Best For: Berberine HCl plus phytosome, third-party tested

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Review with a clinician before buying

Berberine slows liver enzymes that clear many prescription drugs and adds to the effect of glucose-lowering medicines. Review it with your prescribing clinician if you take any medication.

Berberine is a well-researched botanical with a long history of use in traditional Ayurvedic and Chinese herbal practices.

Pros

• Combines the berberine HCl form used in most trials with a phytosome form
• Third-party tested for contents and contaminants
• Sourced from non-endangered plant species

Cons

• Label says not to use if pregnant, nursing or trying to conceive
• Contains pea protein, so the label advises caution with a serious peanut allergy
• Two-capsule serving means a bottle holds 30 servings

Best for Single-ingredient berberine HCl in two bottle sizes

2. Integrative Therapeutics Berberine 500 mg

• Form: Berberine HCl
• Berberine per Capsule: 500 mg
• Label Serving: 1 capsule, two to three times daily
• Bottle: 60 or 120 capsules
• Best For: Single-ingredient berberine HCl in two bottle sizes

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Review with a clinician before buying

Berberine slows liver enzymes that clear many prescription drugs and adds to the effect of glucose-lowering medicines. Review it with your prescribing clinician if you take any medication.

Berberine is an active constituent of many plants including Phellodendron amurense root.

Pros

• Berberine HCl only, the form most trials used
• Free of gluten, soy, dairy and artificial colors
• Available in a 120-capsule bottle

Cons

• Label serving runs up to three capsules a day
• Label says not to use if pregnant or nursing

Best for Insulin Resistance and PCOS: Inositol

Inositol is a compound your body makes and also gets from food, and it carries part of insulin’s signal inside cells. It is best studied in polycystic ovary syndrome (PCOS), where insulin resistance is common. In a meta-analysis of nine randomized trials in women with PCOS, myo-inositol alone or combined with D-chiro-inositol lowered fasting insulin and HOMA-IR compared with controls ^[2]. That evidence is specific to PCOS. Trials of inositol for insulin resistance in people without PCOS are fewer. For more on the link between the two, see PCOS and insulin resistance.

Best for Myo-inositol and D-chiro-inositol in a 40:1 ratio

1. Theralogix Ovasitol Inositol Powder

• Form: Myo-inositol and D-chiro-inositol in a 40:1 ratio
• Amount per Scoop: 2,000 mg myo-inositol and 50 mg D-chiro-inositol
• Label Serving: 1 level scoop stirred into a drink, twice daily
• Bottle: 400 g tub (about 90 days at the label serving)
• Best For: Myo-inositol and D-chiro-inositol in a 40:1 ratio

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With an evidence-based blend of D-chiro-inositol and myo-inositol, Ovasitol is designed to promote healthy hormone levels to support regular menstrual cycles, ovarian health, and fertility.

Pros

• Both forms of inositol studied in PCOS, in one powder
• No other ingredients
• One tub lasts about three months at the label serving

Cons

• Powder has to be mixed into a drink twice a day
• Marketed for cycle and fertility support rather than blood sugar

Best for Plain myo-inositol powder with no other ingredients

2. Vital Nutrients Inositol Powder

• Form: Myo-inositol powder
• Amount per Serving: 3,800 mg per rounded teaspoon
• Label Serving: 1 rounded teaspoon in juice or water, twice daily
• Bottle: 225 g (about 59 servings)
• Best For: Plain myo-inositol powder with no other ingredients

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Inositol is a compound found in a wide range of tissues, with higher concentrations in the heart and brain.

Pros

• Myo-inositol only, with no other ingredients
• Vegan
• Dissolves in water with a slightly sweet taste

Cons

• No D-chiro-inositol
• Measured by rounded teaspoon, which is less exact than a scoop

Best for After-Meal Spikes: Psyllium and Glucomannan

Soluble, gel-forming fiber slows how quickly carbohydrate is absorbed after a meal. Psyllium has the strongest evidence of any fiber. In a meta-analysis of 35 randomized trials, psyllium taken before meals lowered fasting glucose by 37 mg/dL and HbA1c by 0.97 percentage points in people being treated for type 2 diabetes ^[3]. The effect tracked how high glucose was to begin with: modest in prediabetes, and no significant lowering in people with normal glucose ^[3]. Glucomannan, a fiber from konjac root, lowered fasting glucose by about 7 mg/dL across 14 trials, with a smaller benefit in people with impaired glucose metabolism ^[6]. Getting more fiber from food works the same way, and how to reverse prediabetes covers the wider plan.

Best for Psyllium husk, the most studied fiber for blood sugar

1. NOW Foods Psyllium Husk Powder

• Form: Psyllium seed husk powder
• Fiber per Serving: 7 g (6 g soluble) per level tablespoon
• Label Serving: 1 level tablespoon mixed into at least 12 oz of water or juice
• Third-Party Testing: Made in a GMP facility
• Bottle: 340 g or 680 g (about 37 or 75 servings)
• Best For: Psyllium husk, the most studied fiber for blood sugar

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Excellent source of fiber.

Pros

• Psyllium is the only ingredient
• Two tub sizes
• Soluble fiber amount stated on the label

Cons

• Has to be mixed with plenty of liquid and drunk right away
• Label advises starting with smaller amounts and building up over several weeks

Best for Konjac fiber in capsules taken before meals

2. Nature's Way Glucomannan

• Form: Glucomannan from konjac root
• Fiber per Serving: About 2 g glucomannan per 3 capsules
• Label Serving: 3 capsules with a full glass of water, about 20 minutes before a meal
• Bottle: 100 capsules (about 33 servings)
• Best For: Konjac fiber in capsules taken before meals

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Promotes feelings of fullness.

Pros

• Capsules, with no mixing
• Authenticity tested by an independent third party (TRU-ID)

Cons

• Label warns it can cause choking without enough liquid, and not to use it if you have trouble swallowing
• Three-capsule serving

Best for Fasting Glucose: Cinnamon

Cinnamon is one of the most popular blood sugar supplements, and its evidence is mixed. A meta-analysis of 10 randomized trials in type 2 diabetes found cinnamon lowered fasting glucose by about 25 mg/dL but had no significant effect on HbA1c, and the trials varied widely in dose (120 mg to 6 g a day) and length ^[7]. A Cochrane review of 10 trials found the fasting glucose effect inconclusive and insufficient evidence to support cinnamon for diabetes ^[8]. Cassia cinnamon, the type most sold in the US, contains varying amounts of coumarin, which NCCIH notes might worsen liver disease in large amounts ^[4]. Treat cinnamon as a possible small help, not a proven one.

Best for Ceylon cinnamon at 500 mg per capsule

1. Carlson Labs Ceylon Cinnamon

• Form: Ceylon cinnamon bark (Cinnamomum verum)
• Cinnamon per Capsule: 500 mg
• Label Serving: 1 capsule twice daily, at mealtime
• Bottle: 90 capsules
• Best For: Ceylon cinnamon at 500 mg per capsule

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Derived from Cinnamomum verum plant bark, Ceylon Cinnamon has been used since as early as 2800 BC and is mentioned in one of the earliest books on Chinese botanical medicine.

Pros

• Ceylon rather than cassia cinnamon
• Sugar-free and preservative-free

Cons

• Beef gelatin capsule, so not vegetarian
• Lower daily amount than the 2 g average in the Cochrane trials

Best for Once-daily cinnamon extract in a vegetarian capsule

2. New Chapter Cinnamon Force

• Form: Cassia and Ceylon cinnamon bark extracts in olive oil
• Cinnamon per Capsule: 105 mg cassia and 35 mg Ceylon extract
• Label Serving: 1 capsule daily with food
• Bottle: 30 or 60 capsules
• Best For: Once-daily cinnamon extract in a vegetarian capsule

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Whole-food Cinnamon helps maintain healthy blood sugar levels.

Pros

• One capsule a day
• Vegetarian and certified gluten-free by NSF

Cons

• Mostly cassia cinnamon
• Far less cinnamon per day than most trials used

Best for Nerve Support: Alpha-Lipoic Acid

Alpha-lipoic acid (ALA) is an antioxidant studied mainly for nerve symptoms in diabetes rather than for blood sugar itself. In the SYDNEY 2 trial of 181 people with diabetic nerve pain, 600 mg of oral ALA once daily for five weeks reduced symptom scores by 51%, against 32% on placebo, and higher doses added nausea, vomiting and dizziness without more benefit ^[9]. The wider evidence is mixed: NCCIH reports reviews with inconsistent findings for nerve symptoms, and a 2019 review of 10 studies found ALA no better than placebo for lowering blood sugar ^[4].

Best for 600 mg per capsule, the dose tested in SYDNEY 2

1. Pure Encapsulations Alpha Lipoic Acid 600 mg

• Form: Alpha-lipoic acid (thioctic acid)
• ALA per Capsule: 600 mg
• Label Serving: 1 to 2 capsules daily, in divided doses with meals
• Bottle: 60 or 120 capsules
• Best For: 600 mg per capsule, the dose tested in SYDNEY 2

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Alpha Lipoic Acid is a water and fat soluble antioxidant.

Pros

• The once-daily dose SYDNEY 2 found had the best balance of benefit and side effects
• Hypoallergenic and vegan

Cons

• A 600 mg capsule cannot be split into smaller amounts

Best for Sustained-release tablet in a smaller dose

2. Jarrow Formulas Alpha Lipoic Sustain 300 mg

• Form: Alpha-lipoic acid in a bilayer quick- and sustained-release tablet
• ALA per Tablet: 300 mg, with 330 mcg biotin
• Label Serving: 1 tablet, one or two times daily with meals
• Bottle: 60 or 120 tablets
• Best For: Sustained-release tablet in a smaller dose

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Alpha Lipoic Acid (ALA) is an antioxidant that supports normal glucose metabolism and cellular energy production.

Pros

• Sustained-release design
• Smaller per-tablet dose
• Free of wheat, gluten, soy and dairy

Cons

• Also contains biotin, so it is not a single-ingredient ALA

Best for Filling Gaps: Chromium and Magnesium

Chromium helps insulin do its job, and a diet very low in chromium impairs glucose use ^[4]. Trial results for supplements are split. A 2014 meta-analysis of 25 trials in diabetes found chromium lowered HbA1c by 0.55 percentage points and fasting glucose by 1.15 mmol/L, with the clearest effects for chromium picolinate ^[10]. A 2016 review of 20 trials in type 2 diabetes found that only a few reached clinically meaningful targets and concluded chromium has limited effectiveness ^[11]. NCCIH notes that the long-term effects of chromium supplements have not been well studied ^[4].

Magnesium is involved in how the body processes glucose. In a meta-analysis of placebo-controlled trials, magnesium supplements lowered fasting glucose in people with diabetes and improved insulin sensitivity markers in people at high risk of diabetes ^[12]. Supplemental magnesium has an adult upper limit of 350 mg a day, according to NCCIH ^[4]. For forms and brands, see the best magnesium supplements.

Best for Chromium picolinate, the form most trials used

1. Thorne Chromium Picolinate

• Form: Chromium picolinate
• Chromium per Capsule: 500 mcg
• Label Serving: 1 capsule, one to two times daily
• Bottle: 60 capsules
• Best For: Chromium picolinate, the form most trials used

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Thorne’s Chromium Picolinate provides chromium that is bound to picolinic acid, which facilitates its absorption, so you get chromium’s full benefit.

Pros

• The chromium form with the clearest trial effects
• Short ingredient list

Cons

• Mixed evidence for blood sugar
• Long-term effects of chromium supplements are not well studied

Best for Gentle magnesium in a dose that is easy to adjust

2. Pure Encapsulations Magnesium Glycinate 120 mg

• Form: Magnesium glycinate
• Magnesium per Capsule: 120 mg
• Label Serving: 1 to 4 capsules daily with food
• Bottle: 90, 180 or 360 capsules
• Best For: Gentle magnesium in a dose that is easy to adjust

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This highly bioavailable form of magnesium chelate glycinate is less likely to cause loose stools in sensitive individuals than other forms of magnesium.

Pros

• Glycinate is less likely to cause loose stools than other forms
• Small per-capsule dose
• Three bottle sizes

Cons

• Higher amounts take several capsules

What to Look For in a Blood Sugar Supplement

1. A Baseline Test

The trials above measured change in HbA1c, fasting glucose and fasting insulin. Knowing your own numbers before you start is the only way to tell whether a supplement is doing anything, and the biggest effects in the psyllium trials were in people whose glucose was highest to begin with ^[3].

2. Your Medication List

Any supplement that lowers blood sugar can add to the effect of metformin, sulfonylureas or insulin, which raises the risk of low blood sugar, and berberine also changes how the liver clears other drugs ^[5]. NCCIH advises people who take diabetes drugs to tell their health care providers about any supplements they use ^[4]. If you take any prescription medication, review a new supplement with your prescribing clinician first.

3. The Form on the Label

• Berberine: berberine HCl is the form in most trials.
• Inositol: myo-inositol, alone or with D-chiro-inositol, is the form in the PCOS trials.
• Fiber: psyllium husk has the most glucose evidence; glucomannan has less.
• Cinnamon: the label should say whether it is Ceylon or cassia.
• Chromium: picolinate showed the clearest effects.

4. Stated Amounts, Not Blends

“Glucose support” blends often combine berberine, cinnamon, chromium and herbs in small or undisclosed amounts. That makes it hard to compare with the studies and easy to double up on glucose-lowering ingredients.

5. Quality Signals

Look for third-party certification such as NSF or USP, or at minimum manufacturing in a GMP-certified facility. For what each seal does and does not verify, see how to choose a supplement brand.

Cost Comparison

Each product card above shows its current price from the Mito catalog. To compare cost per serving, divide that price by the servings per bottle below. Some labels allow more than one serving a day, so a bottle of those lasts fewer days at the higher amount.

Test This with Mito

Blood sugar supplements are judged by blood tests. Testing first tells you where you stand, and retesting after about three months tells you whether anything changed.

• Hemoglobin A1c (HbA1c): your average blood sugar over the past two to three months, the main outcome in the berberine, psyllium and chromium trials ^[1][3][10].
• Fasting insulin: often rises before fasting glucose does when insulin resistance is building, and was an outcome in the berberine and inositol trials ^[1][2].
• Fasting glucose: a snapshot of your blood sugar after an overnight fast.
• Insulin Resistance Panel with Score: combines insulin and C-peptide measurements into an insulin resistance score in one draw.

To understand what fasting insulin shows, read understanding the fasting insulin test. For the signs and causes of insulin resistance, see insulin resistance: signs, tests and reversal.

Key Takeaways

• No supplement replaces diabetes medication, and several add to its glucose-lowering effect.
• Berberine has the most trial evidence for HbA1c and fasting glucose, mostly from small trials, and it interacts with other drugs.
• Myo-inositol has the clearest evidence for insulin resistance in women with PCOS.
• Psyllium helps most when glucose is high, and food fiber works the same way.
• Cinnamon, chromium and alpha-lipoic acid have mixed evidence for blood sugar.
• Test before and after with HbA1c, fasting glucose and fasting insulin.

Related Content

• How to Improve Insulin Sensitivity
• How to Lower A1C Naturally
• Insulin Resistance: Early Signs, Best Tests, and How to Reverse It
• How to Reverse Prediabetes
• PCOS and Insulin Resistance
• Understanding the Fasting Insulin Test
• Best Magnesium Supplements: Brands Ranked by Quality

Medical Disclaimer

This article is for educational purposes only and is not medical advice. It does not diagnose or treat any condition. Do not start, stop or change a diabetes medication based on this article. If you have diabetes, take prescription medications, are pregnant or breastfeeding, or have kidney or liver disease, discuss any supplement with your doctor first.

References

1. Guo J, Chen H, Zhang X, et al. The Effect of Berberine on Metabolic Profiles in Type 2 Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Oxid Med Cell Longev. 2021;2021:2074610. PMC8696197
2. Unfer V, Facchinetti F, Orrù B, Giordani B, Nestler J. Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials. Endocr Connect. 2017;6(8):647-658. PMC5655679
3. Gibb RD, McRorie JW Jr, Russell DA, Hasselblad V, D’Alessio DA. 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;102(6):1604-14. PMID: 26561625
4. National Center for Complementary and Integrative Health. Diabetes and Dietary Supplements: What You Need To Know. nccih.nih.gov
5. Guo Y, Chen Y, Tan ZR, Klaassen CD, Zhou HH. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol. 2012;68(2):213-7. PMC4898966
6. Sood N, Baker WL, Coleman CI. Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis. Am J Clin Nutr. 2008;88(4):1167-75. PMID: 18842808
7. Allen RW, Schwartzman E, Baker WL, Coleman CI, Phung OJ. Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis. Ann Fam Med. 2013;11(5):452-9. PMC3767714
8. Leach MJ, Kumar S. Cinnamon for diabetes mellitus. Cochrane Database Syst Rev. 2012;(9):CD007170. PMC6486047
9. Ziegler D, Ametov A, Barinov A, et al. Oral treatment with alpha-lipoic acid improves symptomatic diabetic polyneuropathy: the SYDNEY 2 trial. Diabetes Care. 2006;29(11):2365-70. PMID: 17065669
10. Suksomboon N, Poolsup N, Yuwanakorn A. Systematic review and meta-analysis of the efficacy and safety of chromium supplementation in diabetes. J Clin Pharm Ther. 2014;39(3):292-306. PMID: 24635480
11. Costello RB, Dwyer JT, Bailey RL. Chromium supplements for glycemic control in type 2 diabetes: limited evidence of effectiveness. Nutr Rev. 2016;74(7):455-68. PMC5009459
12. Veronese N, Dominguez LJ, Pizzol D, Demurtas J, Smith L, Barbagallo M. Oral Magnesium Supplementation for Treating Glucose Metabolism Parameters in People with or at Risk of Diabetes: A Systematic Review and Meta-Analysis of Double-Blind Randomized Controlled Trials. Nutrients. 2021;13(11):4074. PMC8619199

Frequently asked questions

What is the best supplement for lowering blood sugar?

Berberine has the largest body of trial evidence. A 2021 meta-analysis of 46 trials in people with type 2 diabetes found berberine, alone or added to standard care, lowered HbA1c by about 0.7 percentage points, though most trials were small and conducted in China. Psyllium fiber also lowered fasting glucose and HbA1c in people being treated for type 2 diabetes. Cinnamon, chromium and alpha-lipoic acid have weaker or mixed results.

Can supplements replace metformin or other diabetes medication?

No. No supplement has been shown to replace diabetes medication, and the National Center for Complementary and Integrative Health warns that products claiming to replace your diabetes medicine are marketed illegally. Several supplements in this guide can add to the glucose-lowering effect of metformin, sulfonylureas or insulin, which raises the risk of low blood sugar. Do not stop or reduce a prescribed medication in favor of a supplement.

What supplements help with insulin resistance?

Myo-inositol and berberine have the most direct evidence. In a meta-analysis of nine randomized trials in women with PCOS, myo-inositol lowered fasting insulin and HOMA-IR, a measure of insulin resistance. Berberine trials in type 2 diabetes reported lower fasting insulin and HOMA-IR as well. Magnesium improved insulin sensitivity markers in people at high risk of diabetes. A fasting insulin test tells you whether insulin resistance applies to you.

Is it safe to take berberine with metformin?

Many berberine trials added it to standard diabetes treatment, but combining the two raises the risk of low blood sugar, and berberine slows several liver enzymes that clear other prescription drugs. Berberine is also not recommended during pregnancy or breastfeeding. Adding it to a diabetes medication is a decision to make with whoever prescribes that medication.

Does cinnamon lower A1C?

The evidence says probably not. A meta-analysis of 10 trials in type 2 diabetes found cinnamon lowered fasting glucose but had no significant effect on HbA1c, and a Cochrane review found insufficient evidence to support cinnamon for diabetes. The trials varied widely in dose, cinnamon type and length.

How do I know if a blood sugar supplement is working?

Retest the same markers you started from. HbA1c reflects your average blood sugar over about three months, so it is the most useful measure of change. Fasting glucose and fasting insulin show shorter-term shifts. Most trials in this guide measured results after 4 to 12 weeks or longer.