This is the structural argument, and it is an argument, not a quoted fact, so take it as the inference it is: a molecule this large and this complex, with no legitimate manufacturer and no reference standard, produced by the cheapest possible synthesis for an unregulated market, is close to impossible to make cleanly and impossible for the buyer to verify
Keep in mind: These factors may contribute to discomfort, but they are not the only possible explanation for symptoms
But this is very unlikely to happen given the huge investments companies like Eli Lilly and Novo Nordisk are making in these medications
Deficiencies are less common in developed countries but can occur in people with restrictive diets, alcoholism, or malabsorption
Participants, site personnel, the clinical study group, and investigators were masked to the randomised treatment