What is Humulin (human insulin)?

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Last updated: May 1, 2025 • View editorial policy

From the Guidelines

Humulin I should be used as part of a comprehensive diabetes management plan, with a focus on individualized dosing and blood glucose monitoring to minimize the risk of hypoglycemia and other complications, as supported by the most recent guidelines from the American Diabetes Association 1.

Key Considerations for Humulin I Use

  • Humulin I is an intermediate-acting insulin preparation containing isophane insulin (NPH insulin), with an onset of action within 1-2 hours after injection, peaking at 4-12 hours, and a duration of up to 24 hours 2.
  • The usual starting dose for adults with Type 2 diabetes is 10-20 units once or twice daily, while dosing for Type 1 diabetes is more individualized, with total daily insulin requirements estimated based on weight, ranging from 0.4 to 1.0 units/kg/day 2.
  • Humulin I appears cloudy and requires gentle rolling between the palms (not shaking) before administration to ensure proper mixing, and is typically injected subcutaneously into the abdomen, thigh, or upper arm, with injection sites rotated to prevent lipodystrophy 2.
  • Common side effects include hypoglycemia, injection site reactions, and potential weight gain, emphasizing the need for careful monitoring and dose adjustment 2.

Recent Guidelines and Recommendations

  • The American Diabetes Association recommends intensive insulin management using a version of continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring for most individuals with type 1 diabetes, with automated insulin delivery (AID) systems considered for those capable of using the device safely 1.
  • The guidelines also emphasize the importance of individualized treatment plans, considering factors such as cost, insulin type and dosing regimen, and self-management capabilities 1.
  • While long-acting insulin analogues may be considered for adults with type 1 or type 2 diabetes who experience frequent severe hypoglycemia with human insulin, the benefits must be weighed against the potential costs and complexities of treatment 3, 4, 5, 6.

From the Research

Humulin I

  • Humulin I is an intermediate-acting insulin, but the provided studies do not directly discuss Humulin I.
  • However, the studies compare intermediate-acting insulin with long-acting insulin in type 1 diabetes mellitus 7.
  • The study found that long-acting insulin preparations seem to exert a beneficial effect on nocturnal glucose levels, but their effect on overall diabetes control is clinically unremarkable 7.
  • Other studies discuss the use of metformin in combination with continuous subcutaneous insulin infusion (CSII) for the treatment of type 1 diabetes 8 and type 2 diabetes 9, 10.
  • These studies found that metformin can be an insulin-sparing agent when used in combination with CSII, and it can lead to a significant reduction in insulin doses required by patients to maintain glycemic control 8, 9.
  • A study comparing CSII with basal insulin plus oral hypoglycemic agents found that both treatments had similar effects on glycemic control and beta-cell function in newly diagnosed type 2 diabetes patients 10.
  • Another study found that CSII did not produce any significant improvement in HbA1c compared with multiple daily injections in type 2 diabetic patients 11.

References

Research

Intermediate acting versus long acting insulin for type 1 diabetes mellitus.

The Cochrane database of systematic reviews, 2008

Research

Continuous subcutaneous insulin infusion versus multiple daily insulin injections in type 2 diabetes: a meta-analysis.

Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.