Humulin® N Insulin Vial (Insulin Isophane NPH) 100 units/mL

What Is Humulin® N (Insulin Isophane NPH)?

Humulin N is an intermediate-acting insulin suspension formulated with neutral protamine Hagedorn (NPH) technology. By combining human insulin with protamine, absorption from the subcutaneous tissue is delayed, producing a prolonged glucose-lowering effect compared with short-acting insulin.

It is indicated for the treatment of adults and children with type 1 or type 2 diabetes who require insulin to achieve glycaemic control. As outlined in guidance from the NHS overview of diabetes management, maintaining stable blood glucose levels is essential in reducing the risk of long-term complications such as cardiovascular disease, neuropathy, nephropathy, and retinopathy.

The vial presentation allows flexible dose measurement using an insulin syringe, which some patients and clinicians prefer for tailored dose adjustments. Each vial contains a sterile suspension of 100 units of insulin isophane per millilitre.

Why Choose Humulin® N Insulin Vials?

Humulin N remains a widely used basal insulin option worldwide. Key considerations include:

• Established clinical experience: NPH insulin has been used for decades with well-understood pharmacodynamics.
• Flexible dosing: Vial and syringe administration allows precise titration.
• Cost-effective therapy: Often more affordable than newer analogue insulins.
• Compatible regimens: Frequently combined with rapid- or short-acting insulin for comprehensive glucose management.

For many patients with type 2 diabetes requiring basal coverage, or individuals with type 1 diabetes using structured basal-bolus therapy, NPH insulin remains a clinically appropriate and economically accessible option.

How Humulin® N Works

After subcutaneous injection, the protamine-insulin complex in Humulin N gradually dissolves, releasing insulin into the bloodstream over an extended period. This mechanism results in:

• Onset of action: Approximately 1–2 hours after injection
• Peak activity: Typically 6–8 hours post-injection
• Duration: Up to 18–24 hours

Because Humulin N has a defined peak, blood glucose monitoring is particularly important to reduce the risk of hypoglycaemia during peak action. Its intermediate duration makes it suitable for once- or twice-daily dosing schedules.

In people with type 1 diabetes, it is commonly used alongside rapid-acting insulin at mealtimes. In type 2 diabetes, it may be used alone or in combination with oral antidiabetic medicines.

Dosage and Administration

Each Humulin N vial contains 100 units/mL insulin isophane suspension. Dosage is individualised and determined by a healthcare professional based on blood glucose readings, dietary intake, physical activity, and overall treatment goals.

General Dosing Guidance

• Administered subcutaneously once or twice daily
• Often timed before breakfast and/or evening meal
• May be combined with short-acting insulin where required

Injection Technique

• Inject into the abdomen, thigh, or upper arm
• Rotate injection sites within the same region
• Do not administer intravenously
• Not suitable for use in insulin pumps

Preparing the Vial

As Humulin N is a suspension, it must be gently mixed before use. Roll the vial carefully between the palms until the liquid appears uniformly cloudy. Do not shake vigorously, as this may cause air bubbles and inaccurate dosing.

Step-by-Step: How to Use Humulin® N from a Vial

1. Wash hands thoroughly.
2. Roll the vial gently between your hands to mix the suspension.
3. Clean the rubber stopper with an alcohol swab.
4. Draw air into the syringe equal to your prescribed dose.
5. Insert the needle into the vial and inject the air.
6. Turn the vial upside down and withdraw the required dose.
7. Check for air bubbles and remove them by tapping the syringe.
8. Inject subcutaneously into the chosen site.

Dispose of used needles in an approved sharps container. Never share syringes or insulin vials.

Storage Requirements

• Unopened vials: Store in a refrigerator at 2°C–8°C.
• Do not freeze. Discard if frozen.
• Opened vial: May be kept at room temperature (below 30°C) for up to 31 days.
• Protect from direct heat and sunlight.

Always check expiry dates and inspect insulin before administration. Do not use if the suspension contains clumps or solid white particles that do not resuspend evenly.

Possible Side Effects

Common Side Effects

• Hypoglycaemia (low blood sugar)
• Weight gain
• Injection site redness, swelling, or itching
• Peripheral oedema (swelling of hands or feet)
• Lipodystrophy at injection sites

Serious Adverse Effects

• Severe hypoglycaemia requiring assistance
• Allergic reactions, including rash or anaphylaxis

Hypoglycaemia is the most frequent complication of insulin therapy. Symptoms may include sweating, tremor, palpitations, confusion, or blurred vision. Patients should carry a fast-acting carbohydrate source and monitor blood glucose regularly.

Drug Interactions

Insulin requirements may be affected by other medicines, including:

• Oral antidiabetic agents (e.g., metformin, sulfonylureas)
• Corticosteroids
• Beta-blockers (may mask hypoglycaemia symptoms)
• Diuretics
• ACE inhibitors

Inform your healthcare provider of all prescription, over-the-counter, and herbal products you are taking.

Comparing Humulin® N with Other Insulin Options

Humulin N is pharmacologically similar to other NPH insulin products such as Novolin N. While their mechanisms are comparable, individual patient response may vary.

Compared with long-acting analogue insulins (e.g., insulin glargine), NPH insulin demonstrates a more pronounced peak. For some patients, this peak effect may be advantageous in targeting specific periods of hyperglycaemia; however, it may also require closer monitoring to reduce hypoglycaemia risk.

Ordering Humulin® N Insulin Vials

1. Place your prescription order securely online.
2. Provide a valid prescription as required.
3. Medication is dispensed and shipped to your address.

Patients in the United States may legally import a personal 90-day supply of prescription medication with a valid prescription, subject to regulatory guidelines. Always verify local importation rules before purchasing.

Delivery timelines typically range from 7–14 business days. For full details, consult our shipping policy.

Frequently Asked Questions

Is it legal to purchase Humulin N from international pharmacies?

In many jurisdictions, individuals may import a limited personal supply of prescription medication with a valid prescription. Regulations vary, so confirm with relevant authorities.

How much does Humulin N cost?

Prices vary by supplier and region. Many patients report significant savings compared with domestic retail pharmacy pricing.

Can Humulin N be mixed with other insulins?

Under professional supervision, NPH insulin may be mixed with certain short-acting insulins in the same syringe. Always follow your healthcare provider’s instructions.

Further Information

For comprehensive prescribing details, consult the official Humulin® N Product Monograph.