Can synthetic sugars have an effect on blood sugar?

Synthetic sugar: I'm not sure what you mean by synthetic, but if you're referring to things like high fructose corn syrup, for example, then yes, this can affect blood sugar in those with diabetes/hypoglycemia. Consuming calories will affect blood sugar sooner or later (esp with diabetes). If i did not understand your question properly, please explain and resubmit. I would be happy to look at it again.