For people who are overweight, it looks like. It makes one wonder if it would only work for them, or if long COVID affects them more.

I had the same question. Apparently people who had already been taking Metformin for diabetes were at lower risk of severe Covid [1], which explains why Metformin is being studied.

Looks like the same authors found that Metformin as a treatment after Covid diagnosis did not significantly reduce the the risk of hospitalization or death, even though it does reduce incidence of long Covid.

[1] https://www.covid19treatmentguidelines.nih.gov/therapies/mis...

[2] https://www.nejm.org/doi/full/10.1056/NEJMoa2201662

Yep - the long Covid endpoint was a secondary one that was added to the trial once people realized that might be an issue. The original trial was to see whether administering metformin / fluvoxamine / ivermectin would have any impact on disease severity.

https://clinicaltrials.gov/study/NCT04510194?term=NCT0451019...

Spoiler: "None of the three medications that were evaluated prevented the occurrence of hypoxemia, an emergency department visit, hospitalization, or death associated with Covid-19." [https://pubmed.ncbi.nlm.nih.gov/36070710/]

But they already had this population enrolled when Long Covid started becoming an issue, so they extended the study to see what impact the same 3 drugs would have on incidence.