Since there are no exact dosage guidelines for Humulin R, the amount taken will be different for each person. Your doctor will determine the best dosage to fit your needs. However, be sure to take the dosage your doctor prescribes for you. The following information describes dosages that are commonly used or recommended. Your doctor will ultimately prescribe the smallest dosage that provides the desired effect. Then they’ll adjust it over time based on your blood sugar levels and other lab values. Typically, your doctor will start you on a low dosage. Humulin R U-500 contains 5 times as much insulin in 1 mL as Humulin R U-100. It comes in a 3-mL KwikPen (a prefilled injection pen) and a 20-mL vial. Humulin R U-500 contains 500 units of insulin per 1 mL of solution.Humulin R U-100 contains 100 units of insulin per 1 milliliter (mL) of solution.Humulin R comes as a solution that’s given as a subcutaneous injection. Below is information about Humulin R dosage for treating type 1 or type 2 diabetes.