Place them in the refrigerator for a few hours, or ideally, a day. After resting for a day in the fridge, most of the chemically aftertaste should dissipate.
In this recipe, I use sucralose, but you can use whichever sugar substitute you prefer. The sucralose I use is for baking, and measured as sugar would be measured. If you are using a different sugar substitute, you will have to adjust the amount to be the equivalent of 1/2 cup of sugar.