Does Saccharide Isomerate (MOIST72) cause skin darkening in whitening serum?

Regarding your concern about Saccharide Isomerate (specifically MOIST72) potentially darkening your skin when mixed into a whitening serum:

The color of an ingredient itself does not permanently change your skin color. While it is true that some ingredients with very intense colors can temporarily tint the skin when used in leave-on products until washed off, this is not the case for MOIST72.

Based on information about MOIST72 Saccharide Isomerate, its color is not intense enough to significantly darken the formula or cause noticeable temporary skin tinting when used at the manufacturer's recommended concentration.

Therefore, it is unlikely that MOIST72 itself is causing your face to look darker. If you are observing a slight darkening, it might be due to other factors in the formulation or simply a perceived effect.