T1D glossary

Pre-bolus

Also called prebolus, bolus timing, pre-bolusing.

A pre-bolus is a meal bolus given some minutes before eating, so the insulin starts working closer to when the meal raises glucose. ADA guidance says mealtime insulin should ideally go in before meals, and its plan table gives about 15 minutes before eating for rapid-acting insulin. The best timing depends on the insulin type, the glucose before the meal and the meal itself. (ADA Standards of Care 2026, section 9)

Worked example

If a care team's plan says 15 minutes, a 6:00 p.m. dinner means the bolus goes in at 5:45 p.m. A family testing a longer pre-bolus for a meal that spikes might compare 15 and 25 minutes across a few dinners.

Related terms

• Bolus
• Insulin-to-carbohydrate ratio
• Time above range

Sources, quoted

• ADA Standards of Care 2026, section 9: “Prandial insulin should ideally be administered before meals, although the optimal timing depends on the pharmacokinetics of the formulation (regular, rapid-acting analog, or inhaled), the premeal blood glucose level, and the anticipated carbohydrate intake.”
• ADA Standards of Care 2026, section 9: “with premeal insulin ∼15 min before eating”

Every quote above is checked against its source page before each update of this site; last checked 2026-10-06. The worked example is our own arithmetic. This page explains a term; it is not advice for a person's treatment.