Comprehensive medication guide to Humulin N including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$35 copay with commercial insurance (Lilly Insulin Value Program caps most commercial plans at $35/month automatically at participating pharmacies); $35/month cap for Medicare Part D enrollees under the Inflation Reduction Act. Covered Tier 1–2 on most formularies.
Estimated Cash Pricing
Approximately $82–$86 retail list price per 10 mL vial; as low as $25 via Walmart ReliOn NPH OTC or $35/month cap with the Lilly Insulin Value Program savings card for a 30-day supply.
Medfinder Findability Score
78/100
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Humulin N is a brand-name intermediate-acting human insulin made by Eli Lilly and Company. Its generic name is insulin isophane human — commonly called NPH insulin (Neutral Protamine Hagedorn). First approved by the FDA in 1982, Humulin N is one of the most widely used insulin formulations in the United States for managing both Type 1 and Type 2 diabetes.
Available as a 10 mL multi-dose vial and a 3 mL KwikPen prefilled injector, Humulin N is used as a basal (background) insulin. It is injected subcutaneously once or twice daily to provide sustained blood sugar control between meals and overnight. Unlike rapid-acting insulins used at mealtimes, Humulin N manages basal blood sugar levels throughout the day.
A unique feature of Humulin N is that it is available over the counter in most U.S. states — no prescription is required, though patients should work with their healthcare provider for proper dosing guidance.
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Humulin N lowers blood glucose through two primary mechanisms: stimulating peripheral glucose uptake by skeletal muscle and fat tissue, and inhibiting hepatic glucose production (the liver's release of glucose into the bloodstream). It also inhibits lipolysis (fat breakdown) and proteolysis (protein breakdown), and promotes protein synthesis.
What makes Humulin N an intermediate-acting insulin is its formulation: insulin crystals are complexed with protamine sulfate and zinc, which slows the dissolution of insulin at the injection site. This controlled release produces a pharmacokinetic profile of: Onset 1–3 hours, Peak 4–12 hours, Duration 12–18 hours.
This peak-containing profile distinguishes Humulin N from modern long-acting analogs (like insulin glargine or degludec), which have flat, peakless action. The peak means Humulin N provides its strongest glucose-lowering effect 4–12 hours after injection — which is why hypoglycemia risk is highest during that window and why blood sugar monitoring is especially important.
100 units/mL — Injectable suspension (10 mL vial)
Multi-dose vial; draw dose with U-100 insulin syringe
100 units/mL — KwikPen (3 mL prefilled pen)
Dial-a-dose pen in 1-unit increments; disposable
As of 2026, there is no active FDA national shortage of Humulin N. Most large pharmacy chains (CVS, Walgreens, Walmart, Costco) carry it in stock. However, localized pharmacy stock gaps do occur — particularly at smaller independent pharmacies — due to ordering cycles, distribution delays, and elevated demand following Eli Lilly's 2023 price reductions.
Humulin N receives a Findability Score of 78/100, reflecting that it is generally available but patients may need to check more than one pharmacy. The OTC status of Humulin N (available without a prescription in most states) provides an important safety net — patients can request it directly from any pharmacist even without a current prescription.
If your usual pharmacy is out of Humulin N, medfinder can call pharmacies near you to check which ones have it in stock — saving you from calling each pharmacy yourself. Results are texted to you.
Humulin N is not a controlled substance and does not require any DEA scheduling or special certification to prescribe. Any licensed healthcare provider with prescribing authority in the United States can write a prescription for Humulin N. It is also available over the counter in most states without a prescription.
Providers who commonly prescribe Humulin N include:
Endocrinologists (specialists for complex diabetes management, especially Type 1)
Primary Care Physicians and Internal Medicine doctors (most common prescribers for Type 2)
Pediatricians and Pediatric Endocrinologists (for children with Type 1 or Type 2 diabetes)
OB/GYNs and Maternal-Fetal Medicine specialists (for gestational diabetes)
Nurse Practitioners (NPs) and Physician Assistants (PAs) with prescribing authority
Telehealth is widely available for Humulin N prescriptions. Because it is not a controlled substance, telehealth providers can prescribe it after a virtual evaluation without in-person requirements. Platforms including Teladoc, MDLive, and Amwell offer diabetes management services that can include Humulin N prescriptions.
No. Humulin N (insulin isophane human, NPH) is not a controlled substance. It is not scheduled by the DEA and does not require any special DEA registration to prescribe. Any licensed healthcare provider with prescribing authority — including nurse practitioners and physician assistants — can prescribe Humulin N.
Additionally, Humulin N is available over the counter in most U.S. states, meaning patients can request it from a pharmacist without a written prescription. It is kept behind the pharmacy counter — so you must ask the pharmacist specifically. Because it is not a controlled substance, there are no refill restrictions or quantity limits imposed by federal law, though insurance plans may have their own quantity limits per prescription.
The most common side effects of Humulin N include:
Hypoglycemia (low blood sugar) — shakiness, sweating, confusion, dizziness, rapid heartbeat. Most common and most important side effect.
Injection site reactions (redness, swelling, itching, pain)
Lipodystrophy (skin thickening or indentations from repeated injections in the same site)
Weight gain
Edema (fluid retention/swelling)
Severe hypoglycemia (seizures, loss of consciousness) — call 911
Severe allergic reactions/anaphylaxis (rash over whole body, trouble breathing, facial swelling) — call 911
Hypokalemia (low potassium) (muscle weakness, irregular heartbeat)
Heart failure risk when used with TZD medications (pioglitazone, rosiglitazone)
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Novolin N
Novo Nordisk's NPH insulin — same drug class and concentration as Humulin N. Available OTC at Walmart (ReliOn brand, ~$25/vial). Most accessible direct substitute.
Basaglar (insulin glargine)
Eli Lilly long-acting analog; once-daily, peakless 24-hour action. Lower hypoglycemia risk than NPH. Covered by Lilly Insulin Value Program ($35/month cap). Requires prescription.
Lantus (insulin glargine)
Sanofi long-acting insulin analog; once-daily, 24-hour peakless coverage. Biosimilars (Semglee, Rezvoglar) available at lower cost. Requires prescription.
Tresiba (insulin degludec)
Novo Nordisk ultra-long-acting insulin (up to 42 hours); extremely flat profile with lowest hypoglycemia risk among basal insulins. Once-daily dosing. Requires prescription.
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Pramlintide (Symlin)
majorContraindicated for mixing in same syringe. Must be administered as a separate injection at a different site.
Alcohol
majorUnpredictably increases or decreases blood glucose. Can cause dangerous hypoglycemia by blocking hepatic glucose production. Avoid or use with caution and food.
Corticosteroids (prednisone, dexamethasone)
majorCause significant insulin resistance, substantially raising blood sugar. May require dose increase of Humulin N during steroid course.
Beta-blockers (metoprolol, atenolol, propranolol)
moderateMask hypoglycemia symptoms (rapid heartbeat, tremors). Prolong hypoglycemia. Increase blood glucose monitoring frequency.
SGLT2 inhibitors (Jardiance, Farxiga, Invokana)
moderateAdditive blood glucose-lowering effect. May require Humulin N dose reduction to avoid hypoglycemia.
GLP-1 agonists (Ozempic, Victoza, Trulicity)
moderateAdditive blood glucose-lowering effect. Monitor for hypoglycemia; may need to reduce Humulin N dose.
ACE inhibitors / ARBs (lisinopril, losartan)
moderateEnhance insulin sensitivity; may increase hypoglycemia risk. Monitor blood glucose closely.
Thiazolidinediones / TZDs (pioglitazone, rosiglitazone)
moderateCombined use increases risk of heart failure and fluid retention. Report shortness of breath, weight gain, or ankle swelling immediately.
Atypical antipsychotics (olanzapine, quetiapine, risperidone)
moderateAssociated with hyperglycemia and impaired glucose control. Monitor blood sugar closely when starting or adjusting these medications.
Bitter melon / Cinnamon / Fenugreek
minorHerbal supplements with potential blood sugar-lowering effects. May increase hypoglycemia risk when combined with Humulin N.
Humulin N has been a cornerstone of diabetes management since 1982. As an intermediate-acting NPH insulin, it remains an effective and affordable option for basal insulin coverage in both Type 1 and Type 2 diabetes. The 2023 Eli Lilly price reductions — cutting the list price by 70% and capping out-of-pocket costs at $35/month — have made it one of the most financially accessible branded insulins on the market.
While Humulin N is generally available at most pharmacies, localized stock gaps do occur. Patients should refill early, maintain a buffer supply, and know their OTC options. Being proactive about refills and pharmacy access is the most effective way to avoid running out of this critical medication.
If you ever can't find Humulin N at your pharmacy, medfinder will call pharmacies near you and text you which ones have it in stock — eliminating the frustrating process of calling pharmacies one by one. medfinder covers all medications, making it a useful tool for any prescription access challenge.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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