The COVID-19 pandemic has dominated headlines around the world for several years. Throughout this time, the public has been relentlessly bombarded with depressing statistics about mortality, morbidity, and climbing case numbers; not to mention restrictive public health measures that have led to widespread boredom and loneliness. Unsurprisingly, the mere mention of COVID-19 is likely to invoke a whole range of negative emotions in the average person.

Fortunately, some recent developments in COVID-19 research might give cause for celebration rather than despair, particularly for people with type 2 diabetes. Recent studies suggest that type 2 diabetics – who experience greater susceptibility to COVID-19 than the general population – may have a new tool in their arsenal for staying healthy in spite of COVID-19. Specifically, this new development involves a decades-old anti-diabetic medication whose properties may have the unanticipated effect of fighting COVID-19 infection.

What Do We Know About COVID-19?

For nearly three years, the world has reckoned and wrestled with the reality of the COVID-19 pandemic, which has proved especially dangerous for certain vulnerable populations. The elderly, the obese, and those with pre-existing and chronic health complications have been shown to be at substantially greater risk of both becoming infected with SARS CoV-2 (the virus responsible for the COVID-19 disease), and of having more severe and negative health outcomes once infected[1]. Unfortunately, people with diabetes fall squarely in the “chronic illness” category, and as that might suggest, have been observed to experience greater susceptibility to COVID-19[2].

Doctors, researchers, and health authorities have been working in concert throughout the pandemic to understand the virus responsible for COVID-19, in the hopes of developing preventions and cures for the illness. This process has led to some success, with the development of several COVID-19 vaccines as an example. It has also led to a relatively sophisticated understanding of the mechanisms by which COVID-19 infections cause harmful symptoms in their hosts. One prominent proposal suggests that COVID-19 induces a storm of inflammation throughout the body, which irritates and harms tissues throughout the body[3].

Because certain populations remain more vulnerable to COVID-19, some research has focused on understanding and treating COVID-19 within these populations. One recent line of research in particular has made inroads on improving care for diabetic COVID-19 patients. Surprisingly, this line of research did not result in a new medication or treatment technique but has rather highlighted the potential protective properties of a common and decades-old diabetes medication – metformin.

What is Metformin?

Diabetes is a relatively common illness, and most people have some idea of how it is treated. The typical person might imagine a regime of insulin injections taken regularly to control blood sugar levels. The truth of the matter is that diabetes is a much more complicated matter than simply taking insulin, and an entire class of medications exist to treat diabetes – these medications are known as anti-diabetics.

One such lesser-known anti-diabetic medication is called metformin, and though not as old as insulin, it’s been around for a very long time. Metformin, which was discovered nearly a century ago, has been employed relatively successfully as a treatment option for patients with type 2 diabetes. Often taken in conjunction with other anti-diabetic medications, metformin works by improving the body’s ability to respond to its own natural insulin levels. While this can make it useful for type 2 diabetics, who suffer from an insensitivity to the insulin produced in their pancreas, it provides no therapeutic benefit for type 1 diabetics, who lack the ability to produce insulin in the first place.

Metformin has a number of qualities that make it appealing for treatment. Firstly, it has been in use for a very long time and is thus relatively well understood. It is known to have a substantial degree of efficacy in some patients, while also being tolerated relatively well and with few major side effects. Another consequence of its long history is that it is widely available in generic form and is thus relatively inexpensive. At roughly $4 per month for a course of metformin, metformin is unlikely to break the bank for most Americans – especially compared to some modern anti-diabetic drugs on the market.

Please note that this does not constitute a recommendation or endorsement of metformin for any person; only take metformin (or any medication) on the explicit advice of your doctor or healthcare professional, and do not make changes to your diabetes or COVID-19 treatment regimen without consulting them first.

Early Speculations About Metformin and COVID-19

While metformin today mainly enjoys the status of a common and fairly effective antidiabetic, it also has various properties that have interested researchers in other domains of medicine. In fact, some of the earliest research published on metformin sought to examine its potential application as an antiviral drug in the treatment of influenza, Hepatitis C, and Zika virus[4]. These early studies seemed to establish that metformin possessed general antiviral properties that showed some effect against these viruses.[5]

Additionally, metformin has been observed to exhibit general anti-inflammatory effects in subjects taking the medication. Given that COVID-19 is a virus that appears to inflict its harm in large part by inducing inflammation, the combined anti-viral and anti-inflammatory properties of metformin made it an obvious candidate for research into its efficacy as a treatment for COVID-19.

Metformin Studies and Their Results

Several preliminary studies have examined whether the speculations about metformin as a COVID-19 treatment held any weight. The results from these studies were generally promising, showing that diabetic patients being treated with metformin did appear to achieve better COVID-19 health outcomes than their counterparts who were being treated with various other anti-diabetics[6].

Recently, a much larger study[7] was conducted to replicate and solidify the results from these earlier studies. This study achieved similar results and led the researchers to similar conclusions about the efficacy of metformin against COVID-19[8]. A clinical trial was also conducted to pursue the same research question, which determined that metformin treatment lowered the probability of hospitalizations and death due to COVID-19 in overweight patients by 40-50%, depending on how early the medication was administered in the course of the infection.

How Significant are These Results?

The emergence of this line of research does seem promising in terms of its potential for improving COVID-19 health outcomes in diabetics. However, expert opinions on the significance of these results vary, with some experts calling for further research to be conducted before making any definitive recommendations for metformin treatment.

Proponents of the research, such as Dr. Bramante, who conducted the most recent study, argue that, because metformin is already FDA-approved for treating type 2 diabetes, physicians can and should consider dispensing metformin “off-label” (a term describing the practice of prescribing medications for a purpose other than those stated by the manufacturer) to their type 2 diabetic patients at risk of COVID-19 infection. They argue that the relative safety of metformin and the robust understanding of its effects in diabetic patients tilt the risk-to-reward ratio favorably[9].

Still, some dissenting voices, such as Dr. Schaffner of the National Foundation for Infectious Diseases, urge that more research and evidence is needed before they can responsibly recommend the widespread prescription of metformin to type 2 diabetics as a COVID-19 treatment. They claim that further research is required to determine, among many things, the extent to which improved outcomes observed in the metformin-treated groups are the result of metabolic controls, or other hospital interventions not controlled for in the study[10].

Ultimately, the decision for any person to use or not use metformin in preventing or treating COVID-19 is one which must be made exclusively in consultation with their team of trusted healthcare professionals.


As any diabetic person can attest, diabetes is a condition that requires constant vigilance. Even normal, everyday life requires diabetic patients to stay on top of medications, blood sugar levels, and maintain consistency in their diet and exercise patterns. Throwing a global pandemic into the mix, particularly one that poses an outsized risk to diabetics, can cause already elevated stress and anxiety levels to go through the roof.

Fortunately, medical research has been progressing at breathtaking speed, and developments like those described in this article are helping to improve all areas of diabetes management. While metformin is unlikely to be a proverbial silver bullet in the fight against COVID-19, it may help level the playing field in certain cases. Though further research in this area may still be necessary, people affected by diabetes can take some comfort in the initial promise that this research presents.

For those concerned about COVID-19, don’t forget the many other measures that can be taken to reduce your odds of becoming infected. Maintaining a healthy diet, keeping your body weight within a healthy range, practicing social distancing, and wearing a properly-fitting mask are examples of practices you should discuss with your doctor as part of your COVID-19 mitigation plan.