Metformin is as old as the hills, figuratively of course. This popular diabetes drug was first prescribed in France in 1957 as Glucophage. The Food and Drug Administration gave it the green light in 1994.
Metformin got its start centuries ago, though, in the form of French lilac. Herbalists and healers recognized the healing power of this plant (Galega officinalis) to ease a wide variety of symptoms, including those that might have been caused by diabetes.
Drug companies have developed pricey new medications to lower blood sugar. But metformin is still a mainstay, and researchers are exploring a number of new uses for this very old drug.
One of the more intriguing lines of research is against cancer. Both laboratory and epidemiological research demonstrate that metformin has anticancer activity against a number of malignancies. Two large population-based studies show that people who take metformin are less likely to develop breast or colorectal cancer (Diabetes Research and Clinical Practice, May 22, 2020). A review of the medical literature revealed that metformin users appear protected in part from melanoma, endometrial cancer and bone cancer as well (Frontiers in Endocrinology, April 16, 2020). In addition, the drug has benefits for the liver, the kidneys and the cardiovascular system.
Among more than 12,000 men with high-risk prostate cancer, the use of metformin in combination with a statin significantly reduced their risk of dying from prostate cancer (Cancer Medicine, April 2020). Other investigators conducted test tube research showing synergistic effects of metformin and curcumin (the active ingredient in the spice turmeric). This combination helped put the brakes on prostate cancer cells (Nutrition and Cancer, July 13, 2020).
A few other combination therapies also feature metformin. In one study of mice, scientists found that a combination of metformin with certain probiotics had beneficial effects on colorectal cancer (Cancers, July 10, 2020).
Research suggests that metformin might also play a role against esophageal cancer and large B-cell lymphoma (Clinical Cancer Research, July 9, 2020; Cancer & Metabolism, July 6, 2020).
Cancer is not the only condition for which metformin appears helpful. Women with polycystic ovary syndrome (PCOS) often have insulin resistance, even though they may not have Type 2 diabetes. PCOS can affect fertility as well as quality of life, and metformin can help women with this condition ovulate (Fertility and Sterility, September 2017).
Antiaging researchers are also looking at the potential for metformin to extend healthy life span. Preliminary animal research has produced promising results (Cold Spring Harbor Perspectives in Medicine, March 2016).
Despite all of the optimism about future uses for metformin, the drug has downsides. Common side effects include digestive problems such as indigestion, nausea, cramps, gas and diarrhea. Metformin can also interfere with vitamin B12 absorption. More worrisome still is lactic acidosis. Palpitations, rapid pulse, low blood pressure, lethargy and severe nausea could signal this rare medical emergency.