Type 2 Diabetes: How to Calculate Insulin Doses
Sometimes, people with type 2 diabetes need to start insulin therapy. That therapy is unique to the individual depending on how much insulin their body continues to produce as well as their diet, other medications they are using, and how sensitive their cells are to insulin.
About half of the body’s insulin requirements are for background or basal needs. Basal insulin controls blood glucose overnight and between meals. The other half, bolus insulin, controls blood glucose after a meal or as a correction for high blood sugar. People with type 2 diabetes may need just basal, just bolus, or both.
The University of California San Francisco Medical Center offers these tips on how to calculate insulin doses for people with type 2 diabetes:
Bolus Insulin Dose – Carbohydrate Coverage
Generally, one unit of rapid-acting insulin will dispose of 12-15 grams of carbohydrate. This range can vary from 4-30 grams or more of carbohydrate depending on an individual’s sensitivity to insulin. Insulin sensitivity can vary according to the time of day, from person to person, and is affected by physical activity and stress.
Bolus Insulin Dose – High Blood Sugar Correction
Generally, to correct a high blood sugar, one unit of insulin is needed to drop the blood glucose by 50 mg/dl. This drop in blood sugar can range from 15-100 mg/dl or more, depending on individual insulin sensitivities.
Basal Insulin Dose
Bear in mind, this may be too much insulin if you are newly diagnosed or still making a lot of insulin on your own. And it may be too little if you are very resistant to the action of insulin. Talk to your provider about the best insulin dose for you as this is a general formula and may not meet your individual needs.
[First you will need to calculate your body’s total daily insulin requirement. About half that insulin will cover your basal needs:]
- The general calculation for the body’s daily insulin requirement is: Total Daily Insulin (TDI) Requirement (in units of insulin) = Weight in Pounds ÷ 4
- Basal/background insulin dose = 50% of TDI.
The UCSF Medical Center website has calculation examples and other information about insulin types and dosing schedules: