My hypothesis is that a functional zinc deficiency is the cause of most cases of diabetes, and by taking metformin, it will at least, not correct a zinc deficiency, and probably make it worse.
To begin I would like to share that I was born with an undecended testicle (cryptorchidism) that had to be removed surgically when I was 3. My brother was born with hypospadia. I have been studying the genetics and environmental issues around these for the last 15 years.
I carry several high risk genes for diabetes but probably the most relevant is that I carry the homozygous risk alleles for rs2466293 in SLC30A8 which is a zinc transporters gene. So I absorb zinc more slowly than most people.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428214/
"Conclusion ZnT8A detection increases T1D diagnosis rate even in mixed populations. SLC30A8 rs2466293 was associated with T1D predisposition in non-European descents."
I had my serum zinc tested and it was low. So now I need to take 240mg of Zinc Sulphate and eat a lot of oysters to keep my zinc levels up.
I was diagnosed with Lupus and now I no longer present constant symptoms.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7544280/
"Ikaros family zinc finger 1(IKZF1) encodes a lymphoid-restricted zinc finger transcription factor named Ikaros that regulates lymphocyte differentiation and proliferation as well as self-tolerance. Increasing evidence indicates that IKZF1 could contribute to the pathogenesis of autoimmune diseases."
So also understand that my mother had diabetes, an immune disorder, and a mood disorder, all of them linked to zinc deficiency.
So, in studies zinc deficiency has been linked to diabetes:
https://www.mdpi.com/260782
"Zinc deficiency is a risk factor for obesity and diabetes."
And genital abnormalities: (This is just one study, but there are hundreds like it.)
https://www.karger.com/Article/Fulltext/441988
"WT1 is a transcriptional regulator with various functions including signalling in both the embryonic kidneys and gonads. Mutations in this zinc finger transcription factor are associated with Denys-Drash or Frasier syndromes, which result in a broad range of malformations including hypospadias."
So I do not think the problem is metformin. I think the problem is doctors not providing patients with diabetes a full nutritional workup and ignoring the role of nutrition in human health.