Berberine vs metformin: Which is better for blood sugar control?

Key Points

• Berberine and metformin lower blood sugar levels by improving insulin sensitivity
• Both options provide modest weight loss and could help with PCOS symptoms
• Metformin typically works faster, while berberine supplements take a few months of consistent use to show results
• Diet and physical activity remain fundamental for managing blood sugar, whether you take berberine, metformin, or another diabetes medication

When it comes to managing blood sugar, Ozempic is what everyone’s talking about. Recently, however, berberine has been stealing a bit of Ozempic’s thunder. 

It is a natural ingredient that some influencers call “Nature’s Ozempic.” However, it actually works more like the most common diabetes medication, metformin.

As you explore options for blood sugar management, it's helpful to understand how berberine and metformin compare. This guide will show you how these two stack up in terms of effectiveness and safety and what current research reveals about each one.

What is berberine?

Berberine is a bright yellow substance found in nature in plants like barberry, goldenseal, and Chinese goldthread. Traditional Chinese healers have used it to help people with various health issues for hundreds of years.

Scientists today are studying berberine because it might help with conditions like type 2 diabetes and hormonal imbalances such as Polycystic Ovary Syndrome (PCOS).

It's important to know that berberine is a supplement, not a medication. This means the US Food and Drug Administration (FDA) hasn't approved it to treat any specific medical condition.

Think of berberine as being in the same category as vitamins you might buy at a store—it might have health benefits, but it hasn't gone through the same rigorous testing and approval process as prescription medicines.

While the term "Nature's Ozempic" suggests it could help with rapid weight loss, the comparison isn't realistic. Berberine works more like metformin.

What is metformin?

Metformin is a prescription medicine that has been the first choice for treating type 2 diabetes for many years. It belongs to a family of medicines called biguanides.

Gia Eapen, MD, explains, “Metformin is an FDA-approved medication to treat type 2 diabetes and needs a doctor’s prescription and medical supervision. It is also used to treat gestational diabetes. Some doctors prescribe it off-label to help with PCOS.”

Recent studies comparing berberine to metformin have shown interesting results, especially regarding blood sugar control and PCOS symptoms. These early findings suggest that the two may work in similar ways to improve insulin sensitivity.

Berberine vs. metformin: How do they work?

Both berberine and metformin help control blood sugar, and research suggests they work in similar ways in the body.

How berberine affects blood sugar

Berberine activates AMPK (AMP-activated protein kinase), an enzyme that works like a “master switch” for your metabolism. When activated, AMPK helps:

• Increase insulin sensitivity (how well your cells respond to insulin)
• Reduce glucose production in your liver
• Enhance glucose uptake in your muscles
• Improve fat burning

Beyond blood sugar control, berberine also has anti-inflammatory and antimicrobial properties that may offer additional health benefits.

How metformin affects blood sugar

Metformin works by targeting the liver and muscle tissue. It lowers blood sugar by:

• Activating AMPK (similar to berberine), which reduces insulin resistance and improves how cells respond to insulin
• Decreasing glucose production in your liver (a process called gluconeogenesis)
• Reducing glucose absorption in your intestines, lowering after-meal blood sugar spikes
• Increasing glucose uptake in muscle and fat tissue, removing sugar from the bloodstream

“Unlike some diabetes medications that increase insulin production, metformin focuses on helping your existing insulin work better,” says Eapen, MD. “This multi-pronged approach is designed to help lower blood sugar levels effectively without causing dangerously low blood sugar (hypoglycemia) when used alone.”

Berberine vs. metformin for blood sugar control

When it comes to managing blood sugar, research suggests that berberine and metformin may perform quite similarly.

Some studies suggest that berberine and metformin lower blood glucose levels in similar ways. Both of them have been shown to decrease HbA1c levels (3-month blood glucose average), fasting blood sugar levels, and blood sugar spikes after meals (post-prandial).

Berberine blood sugar results

A review of over 46 clinical trials on berberine (covering over 2,000 people who took berberine) revealed that, on average, berberine lowered:

• Fasting blood sugar (morning glucose) by 0.89 points (mmol/L)
• HbA1c (3-month blood sugar average) by 0.75 percentage points
• Post-prandial (blood sugar 2 hours after a meal) by 1.3 points

Some studies showed that berberine was more effective at lowering blood sugar levels when taken together with common diabetes drugs.

While these results show promise, most berberine studies have been small and mainly tested on Chinese populations. We need more research with different types of people and over longer time periods to better understand how berberine affects blood sugar long-term.

For now, metformin has much more research supporting it and has been used successfully to treat type 2 diabetes for a longer time.

Metformin blood sugar results

Studies of people with type 2 diabetes found that metformin lowered:

• Fasting blood sugar by 2-3 points (mmol/L). For people starting with higher blood sugar levels, the reduction can be even greater by up to 4.5 points. As an example, if your morning blood glucose reading is about 240, it could drop to 160
• HbA1c by 1-2 percentage points. Data suggests that the higher your starting HbA1c is, the more improvement you may see with metformin
• Postprandial blood sugar levels depending on the dosage

A doctor may also prescribe metformin together with other meds to help control blood sugar levels, depending on each person’s needs.

Berberine vs. metformin for weight loss

Neither berberine nor metformin should be considered a weight loss medication. Both berberine and metformin may offer modest weight loss, mainly by improving how your body processes sugar and reduces insulin resistance.

Berberine weight loss effects

• A review of 12 clinical studies found that berberine helped reduce Body Mass Index (BMI) by an average of 0.47 points and body weight by about 4.4 pounds.

Metformin weight loss effects

• With metformin, people lose 2-3% of their body weight in the first year of starting the medication. So, if the starting weight is 200 pounds, you may lose about 4-6 pounds in your first year of taking metformin

These results are much less than the 15-20% average weight loss seen with Ozempic, Wegovy, Zepbound, and the newer generation of diabetes and weight loss drugs.

So, although some influencers call berberine “Nature’s Ozempic,” it does not offer the level of weight loss that newer diabetes drugs like Ozempic offer.

Berberine vs. metformin for PCOS

Both berberine and metformin can be helpful for women with polycystic ovary syndrome (PCOS), a common hormonal disorder affecting up to 1 in 10 women of reproductive age.

According to Eapen, MD, “PCOS is now recognized primarily as a metabolic condition, with insulin resistance being a key driver in 60-70% of cases. This insulin resistance contributes to hormonal imbalances, irregular periods, and other symptoms that many women struggle with.”

Berberine could be a part of your overall PCOS treatment plan, depending on a doctor’s evaluation and recommendation.

How berberine may help with PCOS

• Blood sugar control: Berberine helps your body make more insulin and makes it easier for insulin to do its job, improving insulin sensitivity
• Hormone balance: Research shows berberine can decrease free testosterone levels and other androgen markers in women with PCOS
• Menstrual regularity: Berberine may help women with PCOS resume more regular menstrual cycles
• Cholesterol management: Berberine has been shown to lower total cholesterol, "bad" LDL cholesterol, and triglycerides while boosting "good" HDL cholesterol. This is relevant for PCOS because women with this condition have a higher risk of cardiovascular disease—improved cholesterol levels can help address this associated health risk
• Modest weight effects: May contribute to small weight reductions, which can improve PCOS symptoms

Side effects: What to expect

Berberine side effects

Berberine's side effects tend to be milder than metformin's but can still include:

• Constipation
• Flatulence (gas)
• Abdominal discomfort
• Diarrhea (less common than with metformin)

Side effects typically become more noticeable at higher doses. Most berberine brands recommend taking it with meals to minimize the risk of digestive discomfort.

Metformin side effects

Metformin is available in varying doses based on the medication so it is very important to talk to your doctor and read the product label for a full list of side effects. Common metformin brands include Formatet and Glucophage.

In general, the common side effects of metformin include:

• Nausea
• Cough
• Diarrhea
• Stomach pain
• Loss of appetite
• Metallic taste in the mouth
• Lower back pain

Most of these side effects may improve as your body adjusts to the medication. Taking metformin with food can help reduce these symptoms.

In rare cases, metformin can contribute to a serious condition called lactic acidosis, a dangerous buildup of lactic acid in the blood. Long-term use may also lead to vitamin B12 deficiency in some people.

Please do not take metformin or adjust your dosage without a doctor’s evaluation, prescription, and medical supervision.

How to take them: Dosage and timing

Berberine dosage

There is no standard dose for berberine yet. However, clinical studies usually have their participants take 500mg with a meal 2-3 times a day for a total of 1,000-1,500 mg daily.

Berberine brands recommend taking berberine with meals to help reduce potential digestive side effects.

Metformin dosage

Metformin dosage varies based on individual needs, medical conditions, and the specific formulation prescribed. Metformin is also prescribed to be taken along with meals.

In general:

Standard tablets

• Starting dose: Usually 500 mg once or twice daily with meals
• Maintenance dose: Often 500-850 mg taken two to three times daily with meals
• Maximum daily dose: Typically 2,000-2,550 mg per day

Extended-release formulations

• Starting dose: Usually 500-1,000 mg once daily with an evening meal
• Maximum daily dose: Typically 2,000-2,500 mg per day

Metformin may also be prescribed alongside other medications, such as sulfonylureas or insulin, depending on individual treatment needs.

Eapen, MD, notes, “Never adjust your metformin dosage without consulting your healthcare provider. Your doctor will determine the right dosage specifically for you based on your individual blood sugar levels, kidney function, other medical conditions, and how you respond to treatment.”

Berberine vs. metformin: How long before you see results?

Wondering how long until you see results? Here's what you may expect:

• Metformin works faster: Many people notice their blood sugar levels changing within a week. But for the full benefits, you'll need to take it regularly for 2-3 months.
• Berberine takes longer: You might see small improvements in the first month, but research shows you'll need to take it consistently for 3-6 months to get the best results.

Both options need consistent use to work well, but metformin typically shows early results faster than berberine. We also do not have information on how berberine works in the long term.

Final thoughts: Berberine vs. metformin

Both options can help with blood sugar and metabolism, but there are important differences.

Metformin is a prescription medication with decades of safety data. It's FDA-approved specifically for type 2 diabetes, and doctors also prescribe it for conditions like PCOS. Its effectiveness and safety profile are well-established through years of clinical use.

Berberine is still being studied. While early research shows it may lower blood sugar similarly to metformin, the scientific evidence is still developing. As a dietary supplement, tt doesn't require a prescription and has less regulatory oversight.

If you're considering berberine for type 2 diabetes, PCOS, or any other medical condition, it's best to consult with your doctor first and use it under medical supervision.

Diet and exercise make a big difference

The most effective approach to blood sugar management is one that includes a healthy diet rich in whole foods, fiber, lean proteins, and healthy fats, plus regular physical activity. No supplement or medication works as well alone as it does with these lifestyle foundations.

Get personalized support to lose weight and lower blood sugar. Find a dietitian who accepts your insurance.

Frequently Asked Questions (FAQs)

1. Can you take berberine and metformin together?

Some early research suggests that berberine and metformin could be taken together safely. A handful of small studies show that the combination of berberine and metformin may provide enhanced benefits for blood sugar control, improvements in PCOS symptoms, and other health markers.

“Since both berberine and metformin lower blood glucose, there may be a risk of hypoglycemia or low blood sugar,” says Eapen, MD. “So, it’s very important to talk to your doctor before taking berberine with metformin.”

Also, remember berberine is an over-the-counter supplement that has no long-term clinical studies. Most berberine trials have also been conducted on Chinese populations, so its effect on other body types needs more research, and it has been known to interact with other drugs.

2. Is berberine really "natural metformin"?

Some people call berberine “Nature’s metformin” because it works in a similar way to prescription medication, according to a few studies. They both offer modest weight loss benefits and help improve insulin sensitivity, which leads to lower blood sugar levels.

3. How much berberine equals 500mg of metformin?

There's no direct equivalent dosage, as the two substances work differently. Also, as a dietary supplement, berberine is not approved to treat medical conditions.

However, studies comparing their effects typically use 500mg of berberine 2-3 times daily. Metformin dosages vary based on each individual’s needs and should be supervised by a doctor.

4. Why is berberine not FDA-approved?

As a supplement, berberine falls under different regulations than pharmaceuticals in the United States. The US FDA doesn't "approve" supplements the way it does prescription medications.

This doesn't mean berberine is unsafe; it just means that the quality may vary widely from brand to brand. There is also not enough scrutiny to ensure that you get the right dose promised by the product label because that depends on the manufacturing process.

If you’re planning to take berberine supplements, consider looking for one that has undergone rigorous testing and may be certified by one or more third-party quality control organizations.

5. Can diabetes be cured with berberine or metformin?

Neither berberine nor metformin can cure diabetes. Diabetes is a long-term condition that can be managed effectively but not permanently eliminated.

When you hear about "reversing diabetes," this actually means achieving remission—where blood sugar levels return to normal ranges without medication. However, if diet and lifestyle habits change, blood sugar levels may rise again.

Managing diabetes successfully requires a whole-body approach: a diet rich in whole foods and fiber, regular physical activity, stress management, good sleep, and sometimes medication or supplements based on your individual needs.

Take control of your blood sugar with a diabetes dietitian who accepts your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.