A cheap drug used for anti-aging and weight-loss may also prevent long COVID, study finds

• Metformin is a cheap, easy-to-access drug that used for diabetes, weight loss, and even anti-aging.
• A new study found that it also reduced the risk of developing long COVID by 40% in some patients.

The decades-old diabetes drug metformin seems to be all the rage right now. Not only is it thought to be able to help with weight-loss and potentially even anti-aging, but a new study found it could be the most effective drug yet in preventing long COVID.

A study published on June 8 in the medical journal The Lancet found that patients who received metformin when they were first diagnosed with COVID-19 had a 41% reduced risk of developing long COVID 10 months later.

The study had limitations — including that it was only tested on people with overweight or obesity — but it showed promise for the drug as a crucial tool in the fight against long COVID.

"The results of this study are important because long COVID can have a significant impact on people's lives," said Carolyn Bramante, the lead researcher in the study and an assistant professor at the University of Minnesota Medical School, in a press release.

"Metformin is an inexpensive, safe and widely available drug, and its use as a preventive measure could have significant public health implications."

Metformin could be a game-changer — with some caveats

Long COVID means having COVID symptoms that last three or more months after first contracting the virus, according to the CDC. It affects millions of Americans— as many as 7.5% of US adults, or about 24 million people.

Symptoms can include brain fog, fatigue, shortness of breath, heart palpitations, stomach pain, and they can last for weeks or even years. People are more likely to get long COVID the more times they are infected with the disease, according to the World Health Organization.

However, there are still no officially recommended treatments for long COVID. That's why a cheap, easy-to-use medication to prevent long COVID could be a gamechanger. "To see such a pronounced benefit in the current randomized trial of metformin, in the context of it being so safe and low cost, I'd give it a breakthrough categorization," wrote Eric Topol, director of the Scripps Research Translational Institute, on his blog.

There are some caveats to the study's findings:

• First, the study only tested the drug in people between the ages of 30-85 years old with overweight and obesity; we still don't know if metformin would work for different demographics.
• Second, the researchers said it was more effective if participants took the drug in fewer than four days after the onset of COVID symptoms, which may not be so easy in practice for many people. (Topol wrote on his blog that if he were to get COVID, he would take metformin for two weeks just like in this trial.)
• Finally, some of the people who took metformin still did get long COVID: 6.3% of them. That's compared to 10.6% of people who got long COVID while taking a placebo pill.

The study validated that long COVID is a real illness, an emergency room doctor said

Besides showing the benefits of metformin, the study may have had another inadvertent impact: Proving that long COVID does, in fact, exist, according to to Jeremy Faust, an emergency physician at Brigham and Women's Hospital.

In the early days of the pandemic, some doctors dismissed patients who said that they were experiencing long-term symptoms from a viral infection (some doctors still do). While it's not unheard of that a virus can cause a chronic illness, the complicated and diverse symptoms of long COVID made the disease hard to define.

This study may have changed that, according to Faust. In an accompanying comment to the study in the Lancet, Faust wrote that using metformin to treat long COVID proves that long COVID is a real disease. "A treatment can only be effective if there is something to treat," he wrote.

Correction: June 12, 2023 — An earlier headline for this story misstated the results of the study. It found metformin might help prevent long COVID, not that it might help treat it. An earlier version of this story also misstated the conditions in which metformin appeared to be most effective. It seemed more effective when patients took it within three days of symptom onset, not within four days.