Press coverage of COVID-OUT clinical trial highlights metformin

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Metformin has been in the news a lot lately! This common diabetes medication was evaluated in a randomized, double-blind clinical trial called COVID-OUT. As reported in the New England Journal of Medicine by principal investigator Dr. Carolyn Bramante of the University of Minnesota, metformin was effective at substantially reducing emergency room visits, hospitalization or death from COVID-19.

Timing on starting metformin was important. Serious outcomes were reduced by half if the medication was taken within four days of symptom onset.

Metformin was effective in both vaccinated and unvaccinated people. The study included participants over 30 years of age who were classified as overweight based on their BMI or body mass index.

Interestingly, the other existing medications tested (the anti-parasitic ivermectin and the low-dose antidepressant fluvoxamine) did not prove to be effective.

Metformin is extremely inexpensive, has been used for decades, is considered safe for pregnant women, and is available all over the world. Given these characteristics, it’s an important alternative to antiviral drug treatments like remdesivir and Paxlovid that are not available in some parts of the world.

The Parsemus Foundation helped to fund and enroll volunteers in the COVID-OUT trial, and we were pleased to see good media coverage of this important finding. For more details, see the Parsemus Foundation press release (English, SpanishPortuguese). Check out this news story with an interview of Dr. Bramante.

The take-home messages on the COVID-OUT results from Northwestern Medicine:

  • Metformin lowered the odds of emergency visits, hospitalizations, and death by over 40 percent — and over 50 percent if prescribed early in the onset of symptoms
  • Ivermectin and fluvoxamine — also tested in the multi-site clinical trial — were not effective
  • This was one of the largest fully-remote studies, including 1,323 participants
  • This was the first published trial in which a majority of study participants were vaccinated
  • This was among the first randomized clinical trials for COVID-19 to include pregnant people


Linda Brent, PhD

Executive Director, Parsemus Foundation

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