Yes, we know something about individual vitamins. Vitamin B1, by itself, in a given type of tablet, will deteriorate at a rate that can be approximated. People have done the analysis in the past. The vitamin manufacturers make this type of data available. And any time you make a change to a vitamin formulation, the shelf life could be affected.
All vitamins deteriorate over time.
And they do so at different rates. The presence of other ingredients further complicates matters because each ingredient can influence the deterioration rate of other ingredients. We can assure the shelf life by adding overages to the various ingredients. An overage is an extra amount of an ingredient, an amount over the actual label claim. Let s do the math.