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Drug Info

Berberine vs. metformin for diabetes treatment

Metformin is FDA approved to improve blood glucose levels in people with Type 2 diabetes mellitus, while berberine uses include, digestive tract infections, high cholesterol, high blood pressure, and PCOS
Karen Berger medical writer and reviewer headshot
By | Jun. 26, 2024
Comparing two medication bottles: Berberine vs. metformin for diabetes treatment

Key takeaways

  • Berberine is an over-the-counter dietary supplement. The FDA does not approve it for medical conditions. Metformin is an FDA-approved prescription drug specifically used for Type 2 diabetes.

  • Clinical guidelines recommend metformin for treating Type 2 diabetes, and it has proven effectiveness, while berberine is not a mainstay treatment and lacks consistent research support.

  • Metformin is typically covered by insurance and Medicare prescription plans, making it more affordable for long-term use, whereas berberine is not covered and must be purchased out-of-pocket.

  • In terms of side effects, berberine can cause appetite loss, stomach upset, and skin rash, while metformin may lead to nausea, vomiting, diarrhea, and abdominal discomfort.

  • Consult your healthcare provider for more information about your condition and the best treatment for you. 

In this article:

Berberine is a dietary supplement used to help control blood sugar, among other uses. Metformin is approved by the U.S. Food and Drug Administration (FDA) as a prescription drug used to improve blood sugar control in people with Type 2 diabetes. Metformin works by decreasing sugar production in the liver, slowing sugar absorption from food, and helping cells in the body use sugar more effectively. There are many differences between berberine and metformin—continue reading to learn about both.

What are the main differences between berberine and metformin?

Berberine is a dietary supplement that you can purchase over the counter. It is available in various formulations, such as oral capsules or gummies. Metformin is available by prescription only. You cannot purchase metformin over the counter. Metformin has two formulations: an immediate-release form and an extended-release form. 

Main differences between berberine and metformin
Berberine  Metformin 
Drug class Dietary supplement  Biguanide 
Brand/generic status Available in many formulations Generic 
What is the brand name? Various product names Fortamet and Glumetza are brand-name versions of metformin

Brand names Glucophage, Glucophage XR, Riomet, and Riomet XR are no longer available in the U.S. 
What form(s) does the drug come in? Various, such as capsules and gummies Tablet

Extended-release tablet

Oral liquid
What is the standard dosage? 500 mg by mouth three times daily before meals Varies; a typical dose may be to start with 500 mg by mouth twice daily, gradually increasing to a higher dose of 1,000 mg twice daily as directed by the healthcare provider
How long is the typical treatment? Varies Long-term 
Who typically uses the medication? Adults Adults and children 10 years and older (extended-release version is for adults only)

Conditions treated by berberine and metformin

Dietary supplements, like berberine, are not FDA-approved to treat medical conditions like diabetes. They are not considered medicines and cannot be used to treat, diagnose, prevent, or cure medical conditions. While prescription and OTC drugs go through extensive clinical studies, dietary supplements are overseen by the FDA but are not as strictly regulated. Dietary supplements can make statements such as “promoting health” or supporting a body part or function, but all claims are followed by this statement: 

“This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” 

Some of the possible uses of berberine include diabetes, certain types of digestive tract infections, high cholesterol (especially in those with mildly elevated cholesterol who cannot take a statin or who have metabolic syndrome), high blood pressure, and polycystic ovary syndrome (PCOS). Some research suggests it may help with weight loss, but more research needs to be done to determine if berberine can impact body weight.

Metformin is FDA-approved to improve blood glucose levels in people with Type 2 diabetes mellitus. The immediate-release version can be used in adults and pediatric patients 10 years and older, while the extended-release version can be used in adults only. Metformin is generally used along with dietary changes and increased exercise. 

Metformin also has several off-label uses, which means uses that are not approved by the FDA. These include treating PCOS (including infertility treatment), delaying puberty in females with early puberty, treating gestational diabetes, treating prediabetes (and insulin resistance), and treating obesity or high blood sugar due to side effects of antipsychotic medications. 

Is berberine or metformin more effective?

As noted above, berberine is not held to as strict standards as metformin. Moreover, because dietary supplements are not regulated as strictly as prescription and OTC products, there may be problems with the actual product. For example, the dose on the label might not match the exact dose of the supplement. Some dietary supplements have been found to contain contaminants. There is insufficient oversight to ensure dietary supplements’ safety and accuracy.

Clinical guidelines for the treatment of Type 2 diabetes, such as those by the American Diabetes Association, recommend metformin as the first drug of treatment (along with lifestyle changes). Metformin is considered a very effective drug and is safe, well-tolerated, and affordable. 

Many patients will require more than one medication to help with blood glucose control or other co-occurring conditions. This is called combination therapy, and many people require more than one medication right away. For example, people with Type 2 diabetes and certain conditions like heart disease, heart failure, or kidney disease may benefit from medications like GLP-1 agonists or SGLT2 inhibitors in addition to metformin. 

Dietary supplements like berberine have not been proven effective in treating these conditions. Some research has shown berberine to be promising; however, results are conflicting. As of now, while metformin is considered a mainstay of treatment for Type 2 diabetes, berberine is not.

You can consult your healthcare provider for more information and medical advice about berberine and metformin, as only your provider can determine the best treatment for your condition. If you want to try berberine and see if it works for you, that may be an option—just check with your healthcare provider first, as there are many individual factors to consider.

Coverage and cost comparison of berberine vs. metformin

Because berberine is a dietary supplement, it is not typically covered by insurance or Medicare prescription plans. Metformin is generally covered by health insurance and Medicare prescription plans. A typical one-month supply of 60, 500 mg tablets would cost about $190 out of pocket. However, using a free SingleCare card or coupon, you could pay as low as $4. 

Berberine  Metformin 
Typically covered by insurance? No  Yes 
Typically covered by Medicare Part D? No  Yes 
Quantity Varies 60, 500 mg tablets
Typical Medicare copay N/A $0-11
SingleCare cost N/A $4

Common side effects of berberine vs. metformin

Common potential side effects of berberine include:

  • Appetite loss 
  • Upset stomach 
  • Diarrhea or constipation 
  • Rash

Common potential side effects of metformin include:

  • Nausea, vomiting, and diarrhea
  • Gas 
  • Indigestion 
  • Abdominal pain or discomfort
  • Weakness
  • Headache 

Drug interactions of berberine vs. metformin

Before taking berberine or metformin, tell your healthcare professionals about all your medications, including prescription medications, OTC drugs, vitamins, and other supplements. 

Berberine

Berberine interacts with the following:

  • Cyclosporine
  • Dextromethorphan (found in many cough and cold products)
  • Cozaar (losartan)
  • Diabetes medications (may have a hypoglycemic effect, causing low blood sugar)
  • Medications for high blood pressure (may cause low blood pressure)
  • Blood thinners
  • Prograf (tacrolimus)
  • Sedative medicines like sleeping medicines or anxiety medicines

Metformin 

Metformin interacts with the following: 

  • Topamax (topiramate)
  • Zonegran (zonisamide)
  • Diamox (acetazolamide)
  • Ranexa (ranolazine)
  • Tagamet (cimetidine)
  • Alcohol 
  • Insulin or certain diabetes medications (glimepiride, glipizide, glyburide) may result in hypoglycemia
  • Drugs that increase blood sugar, such as diuretics (water pills), steroids, thyroid medications, birth control pills, phenytoin, and others

This is not a full list of drug interactions, and others may occur. Consult your doctor for more information about drug interactions and how they may affect you. 

Warnings of berberine and metformin

Before you take berberine or metformin, make sure your healthcare provider knows about all of your medical conditions and medical history, including if you are pregnant or breastfeeding. 

Berberine is not considered safe to use if you are pregnant or breastfeeding. Metformin is not routinely used during pregnancy but may be required in some cases. 

Metformin has a black box warning, the most serious warning required by the FDA. The warning states that metformin can cause lactic acidosis (a buildup of acid in the blood), which is a medical emergency and can cause serious medical problems and death. Certain individuals are at higher risk for lactic acidosis, such as older adults, people with liver problems, and individuals who drink excess alcohol. Symptoms include feeling unwell, muscle pain, trouble breathing, stomach pain, and extreme drowsiness. These symptoms require emergency medical help in a hospital setting. 

Other warnings include the fact that metformin can cause vitamin B12 deficiency. It can also cause low blood sugar if taken with insulin or certain medications, including Amaryl (glimepiride), glipizide, or glyburide.

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