Metformin is an oral medication primarily used to help reduce blood sugar levels for people with type 2 diabetes. According to a 2019 position statement, the American Diabetes Association (ADA) considers metformin to be a first-line medication because it is typically very effective and has few adverse side effects.
Per the Mayo Clinic, however, there is a growing interest in complementary and alternative medicine for blood sugar regulation. Indeed, a meta-analysis published July 2017 in Frontiers in Pharmacology identifies a number of studies that have examined whether or not herbal supplements can effectively lower blood-sugar levels in people with type 2 diabetes.
But Elizabeth Halprin, MD, clinical director of adult diabetes at Boston's Joslin Diabetes Center, tells LIVESTRONG.com that there are no herbal metformin alternatives.
Dr. Halprin emphasizes that, while herbal supplements can be taken in conjunction with metformin, there is a lack of scientific evidence to recommend this practice. "Some studies show [that supplements] work, and some studies show that they don't," she says. "There's no reason not to take [supplements]. Some people swear by them. But there's no good scientific proof [that supplements are effective]."
This agrees with the Frontiers in Pharmacology analysis, which notes that many studies on herbal supplements are small and of poor quality. Therefore, though some early evidence looks promising, larger studies are needed.
Here is what the current research says about herbal supplements for diabetes.
Herbal Supplements That Show Promise for Those With Diabetes
Limited studies have found that berberine may be as effective as metformin in reducing blood sugar, according to the U.S. National Library of Medicine. Berberine is a chemical compound derived from different plants, including goldenseal, goldthread and tree turmeric.
A meta-analysis published in Evidence-Based Complementary and Alternative Medicine in October 2012 found that patients who took berberine in addition to oral diabetes medicines had lower blood sugar levels than those on oral diabetes medicines alone. The analysis also found that a regimen of berberine plus diet and exercise led to lower blood sugar levels than diet and exercise alone. On a less positive note, however, the researchers found that berberine may cause stomach upset.
A meta-analysis published in the February 2015 Journal of Ethnopharmacology found that people taking berberine on top of their diet and exercise program saw improved hemoglobin A1C levels (which reflect a person's average blood-sugar level over a three-month period and are an important indicator of overall diabetes health). However, the research team noted the limited quality of the studies and cited the need for large, well-designed trials to properly understand berberine's effect on blood sugar.
2. Bitter Melon
Momordica charantia, or bitter melon, has long been used as a remedy for diabetes in a number of indigenous populations, according to an April 2013 review in the Asian Pacific Journal of Tropical Disease.
Some of the compounds in bitter melon may indeed reduce blood sugar, but several research reviews found that the current evidence is inconclusive. The April 2013 study mentioned above, for example, found that although there is much available data, it is flawed due to small sample sizes and poor study design. To date, it is unclear whether or not bitter melon truly has a positive effect on diabetes management.
A number of studies have reported that cinnamon has a positive effect on blood-sugar levels, including a meta-analysis published in the Annals of Family Medicine in September 2013, which found that cinnamon may help lower fasting blood-sugar levels. However, that meta-analysis found no evidence that cinnamon improved hemoglobin A1C levels.
The Mayo Clinic notes that, while there have been numerous studies on cinnamon and diabetes care, some studies have shown a benefit while others have not. High-quality studies are needed to better understand cinnamon's potential as a metformin substitute.
A small study published in the Iranian Journal of Pharmaceutical Research in 2015 found that ginger improved hemoglobin A1C levels for patients with type 2 diabetes. However, much more research is needed to determine ginger's actual benefits for people who have trouble regulating their blood sugar.
Ginseng, a root not unlike ginger, is often used in Korean and Chinese cooking. It is also a staple in traditional Chinese medicine.
Recent studies show that ginseng may have a number of positive effects on people with diabetes. A meta-analysis published in the peer-reviewed scientific journal PLoS One in September 2014 found that ginseng modestly improved fasting blood-sugar levels. Additionally, another smaller study published July 2014 in BMC Complementary and Alternative Medicine found that ginseng lowered post-meal blood sugars. However, more research is needed.
The Verdict on Metformin Alternatives
Though some herbal supplements may complement diabetes medications, there are currently no herbal metformin alternatives. Talk with your doctor if you are interested in adding herbal supplements to your regimen (or are already taking them), as they can sometimes cause adverse side effects and/or interact with other medications. Never stop taking metformin without consulting your doctor.
If you are looking for herbal alternatives to metformin because you are experiencing adverse side effects, you may want to look into taking a different diabetes medication. For example, metformin extended release, also known as metformin HCL, is designed to reduce stomach discomfort, which is the most common metformin side effect.
Is This an Emergency?
- American Diabetes Association: "Standards of Medical Care in Diabetes—2019"
- Mayo Clinic: "Integrative medicine: Alternative becomes mainstream"
- Frontiers in Pharmacology: "An Overview of Herbal Products and Secondary Metabolites Used for Management of Type Two Diabetes"
- Alternative Medicine Review: "Berberine"
- Evidence-Based Complementary and Alternative Medicine: "Berberine in the Treatment of Type 2 Diabetes Mellitus: A Systemic Review and Meta-Analysis"
- Journal of Ethnopharmacology: "Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension"
- Iranian Journal of Pharmaceutical Research: "The Effects of Ginger on Fasting Blood Sugar, Hemoglobin A1c, Apolipoprotein B, Apolipoprotein A-I and Malondialdehyde in Type 2 Diabetic Patients"
- PLoS One: "The effect of ginseng (the genus panax) on glycemic control: a systematic review and meta-analysis of randomized controlled clinical trials."
- BMC Complementary and Alternative Medicine: "Postprandial glucose-lowering effects of fermented red ginseng in subjects with impaired fasting glucose or type 2 diabetes: a randomized, double-blind, placebo-controlled clinical trial"
- Annals of Family Medicine: "Cinnamon Use in Type 2 Diabetes: An Updated Systematic Review and Meta-Analysis"
- Mayo Clinic: "Diabetes treatment: Can cinnamon lower blood sugar?"
- U.S. National Library of Medicine: "Berberine"
- Asian Pacific Journal of Tropical Disease: "Antidiabetic effects of Momordica charantia (bitter melon) and its medicinal potency"
- Alternative Medicine Review: Momordica Charantia (Bitter Melon)
- Alternative Medicine Review: Berberine