The Croatian Phase I and II clinical trials for inflammatory bowel disease conducted in the 1990s by pharmaceutical company Pliva claimed safety with no significant toxicity, though complete peer-reviewed data never appeared in scientific literature beyond conference abstracts
KPV has not been tested in pregnancy, breastfeeding, or in people on immune-modifying drugs, so those groups fall outside the evidence and have the most reason for caution
People with digestive conditions such as Crohn's disease, celiac disease, or other inflammatory bowel conditions often have a compromised gut lining and cannot absorb oral B12 efficiently
If you are not deficient, a B12 injection does not add measurable energy or speed up weight loss
Unlike hormonal compounds, discontinuation simply means return to baseline rather than below-baseline function