Longevity Briefs: Anti-Ageing Candidate Metformin Could Prevent Long Covid

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Long covid is a collection of long-lasting symptoms that can include ‘brain fog’, fatigue, respiratory problems and more. We’re still learning about the causes of the condition, which seems to be related to inflammation in the brain. Metformin is a drug used to control the blood sugar of people with type II diabetes mellitus. It’s also under investigation for its potential anti-ageing effects. Recent studies show that metformin can limit the ability of Sars-CoV-2 to replicate in the lab, but what about its effects in living humans?

What did the researchers do: In this study, researchers recruited 1126 overweight or obese people between the ages of 30 and 85 who had tested positive for COVID-19 within the last 3 days. Being overweight is associated with increased risk of severe COVID-19 complications, although the study did not recruit hospitalised individuals.

Participants were then randomised to receive either two placebo treatments, one of three drugs plus a placebo, or a combination of two drugs. The drugs tested were metformin, the anti-parasitic drug ivermectin, and the antidepressant fluvoxamine. Treatment lasted 14 days and neither participants nor physicians knew which drugs were being given.

Key takeaway(s) from this research:

• Metformin treatment was associated with a 41% reduction in risk of long covid (compared to placebo) after 10 months, while other treatments had no significant effect on long covid risk.
• It’s unknown whether people who already have long covid would benefit from metformin treatment.
• Because the participants were overweight, they may benefit more from metformin treatment than the general population.

10 months after the treatment was given, neither ivermectin nor fluvoxamine significantly reduced the incidence of long covid when compared to a placebo treatment. Metformin, on the other hand, was associated with a 41% reduction in the risk of long covid in comparison to a placebo treatment. There were no significant safety issues associated with metformin.

As mentioned previously, metformin seems to have some antiviral activity, which could have reduced the severity of the initial infection (which may in turn lower the risk of long covid). Metformin also has the ability to suppress inflammation, which is likely to be a key player in long covid. This means there’s a possibility that metformin could benefit people who already have long covid, but more research is needed to investigate this.

It’s important to keep in mind that the participants of this study were all overweight or obese. While only a small percentage had diabetes, they were likely to have above-average blood sugar and increased levels of low-grade chronic inflammation, and so may stand to benefit more from metformin treatment than most. Also, only around 50% of the participants were vaccinated at the time of the treatment and around 25% had some form of heart disease. We will have to wait and see whether the apparent benefits of metformin apply to a healthier population.