Since this formula contains ingredients studied for a supportive role in glucose metabolism, understanding general fasting-blood-sugar-testing timing is worth knowing.
Fasting blood sugar tests are typically taken after 8 or more hours without food, per general medical guidance — worth discussing the ideal testing schedule with your doctor if you're monitoring your levels while taking any supplement.
If you're tracking your blood sugar while taking this formula, worth mentioning that specifically to your doctor so any changes in your readings can be considered in the full context of your routine.