Insulin 70/30 mix — NPH/isophane + regular (Humulin 70/30, Novolin 70/30)

How Medicare covers it

Part D (prefilled pens and vials used at home). Part A during a covered inpatient stay. No Part B row for the mixed insulin in the CMS Part B spending file — the file's pump-insulin codes are for other insulins and are explicitly NOT matched.

What it treats

Humulin 70/30 is used to improve blood sugar control (glycemic control) in adults with diabetes mellitus.

What it is for, in depth

Humulin 70/30 is a fixed-ratio (premixed) insulin for adults with diabetes mellitus who need insulin to control blood sugar. The mix is fixed: 70% insulin isophane human suspension (NPH, intermediate-acting) plus 30% insulin human injection (regular, short-acting), so one injection combines a faster mealtime part with a longer background part. It is a sterile, white and cloudy suspension for use only under the skin. Each milliliter contains 100 units of insulin human (U-100). It comes as a 10 mL multiple-dose vial and as single-patient-use 3 mL KwikPens that dial in 1-unit steps. The dose is not the same for everyone — it is individualized and adjusted using blood sugar monitoring, metabolic needs, and the person's control goal, with added adjustments for drug interactions and for kidney or liver impairment as the full prescribing information directs. It is given about 30 to 45 minutes before a meal. This entry covers only the 70/30 mix, not other Humulin products.

How it works

Insulin lowers blood sugar by helping skeletal muscle and fat take up glucose from the blood and by stopping the liver from making glucose. Insulins also stop the breakdown of fat and protein and help the body build protein. This product mixes two insulins: 70% insulin isophane (NPH), an intermediate-acting insulin, and 30% regular insulin, a short-acting insulin.

How it is taken

Inject only under the skin (subcutaneously) in the belly wall, thigh, upper arm, or buttocks, about 30 to 45 minutes before a meal. Change (rotate) injection sites to lower the risk of lipodystrophy (changes in fat under the skin) and localized cutaneous amyloidosis (lumps of amyloid protein under the skin). The dose is set for each person based on metabolic needs, blood sugar readings, and the blood sugar goal. Forms: a 10 mL multiple-dose vial and 3 mL single-patient-use KwikPens (sold as 5 pens), all at 100 units per mL (U-100). The KwikPen dials in 1-unit steps. Never share a KwikPen or a syringe with another patient, even if the needle is changed.

Common side effects

The main adverse reaction discussed in the label is low blood sugar (hypoglycemia). The label also discusses reactions from insulin mix-up errors, allergic (hypersensitivity) reactions, and low potassium (hypokalemia). Changing injection sites matters because repeated use of one site can cause lipodystrophy and localized cutaneous amyloidosis, as noted in the dosing instructions.

Serious warnings

Never share a Humulin 70/30 KwikPen or syringe between patients, even if the needle is changed. Changing an insulin regimen — strength, maker, type, injection site, or method — can cause high or low blood sugar and must be done under close medical supervision with more frequent blood sugar checks. Hypoglycemia may be life-threatening. Accidental mix-ups between insulin products can cause hypoglycemia, so check the insulin label before every injection. Allergic reactions and low potassium may also be life-threatening. Using this insulin with thiazolidinedione (TZD) drugs can cause fluid retention and heart failure — watch for signs of heart failure and consider lowering the dose or stopping if heart failure occurs.

Who should be careful

Do not use Humulin 70/30 during an episode of low blood sugar, or if you have had an allergic reaction to Humulin 70/30 or any of its ingredients. Extra blood sugar monitoring is needed with changes in dose, other glucose-lowering drugs, meal pattern, or physical activity, and in people with kidney or liver impairment or with hypoglycemia unawareness (not feeling low blood sugar coming on). People at risk for low potassium should have potassium levels monitored. For pregnancy, the label says published studies over decades have not established a link between human insulin use and major birth defects, miscarriage, or bad outcomes for mother or fetus, and it notes the risks of poorly controlled diabetes in pregnancy.

Major interactions

Drugs that may raise the risk of low blood sugar include other diabetes drugs, ACE inhibitors, angiotensin II receptor blockers, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analogs such as octreotide, and sulfonamide antibiotics. Drugs that may weaken the blood-sugar-lowering effect include atypical antipsychotics such as olanzapine and clozapine, corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens, protease inhibitors, somatropin, sympathomimetic agents such as albuterol, epinephrine, and terbutaline, and thyroid hormones. Alcohol, beta-blockers, clonidine, and lithium salts may increase or decrease the effect; pentamidine may cause low blood sugar sometimes followed by high blood sugar. Beta-blockers, clonidine, guanethidine, and reserpine may blunt the signs and symptoms of low blood sugar. Dose changes and more frequent glucose checks may be needed with these drugs.

Cost and saving notes

Medicare caps insulin cost-sharing at $35 for a one-month supply of covered insulin under Part D, and the $35 cap also applies to insulin used in a pump covered under Part B. Check that your specific insulin product is covered by your plan. If you have low income, Extra Help (the Part D Low-Income Subsidy) can also lower Part D costs if you qualify.

Why it is in its tier

Insulin 70/30 mix — NPH/isophane + regular (Humulin 70/30, Novolin 70/30) sits on Tier 3 in 89.03% of the plans that list it (4892 of 5495 listing plans). Tier 3 is the preferred brand tier — mid-level copays or coinsurance. The data-visible drivers: It is a brand-only product with no generic version in the formulary data, and the CMS dashboard puts its average Part D spending at about $638 per beneficiary for 2024 — a relatively low-cost drug, which matches where plans place it. It is listed by 100.0% of Part D plans. The tier shown is the most common one; individual plans vary.

Sources

• HUMULIN 70/30 (INSULIN HUMAN) INJECTION, SUSPENSION HUMULIN 70/30 KWIKPEN (INSULIN HUMAN) INJECTION, SUSPENSION [ELI LILLY AND COMPANY] — DailyMed
• MedlinePlus — Human Insulin Injection

What official patient guides say

Scope: MedlinePlus has no separate page for the 70/30 mix, so this guidance is from the MedlinePlus Human Insulin Injection page, which explicitly covers premixed insulin that contains NPH (Humulin 70/30, Novolin 70/30), and it is scoped here to the packaged premixed 70/30 suspension in vials and pens, injected under the skin. Human insulin is usually injected under the skin several times a day, as often as your doctor tells you, and it should be used exactly as directed — do not use more or less of it or use it more often than prescribed. Because this premixed insulin is a suspension, gently shake it or roll it between your hands to mix it before use, never use it when you have symptoms of low blood sugar or have checked your blood sugar and found it to be low, and be sure the name, letter, and strength on your insulin are exactly what your doctor prescribed and that you know what supplies, such as needles, syringes, or pens, you need. After mixing, a premixed insulin that contains NPH should appear cloudy or milky; do not use it if there are clumps in the liquid or solid white particles sticking to the bottom or walls of the bottle, and do not use any insulin after the expiration date on the bottle. You can inject it in the stomach, upper arm, upper leg, or buttocks — do not inject into muscles, scars, or moles — using a different site for each injection at least 1/2 inch (1.25 centimeters) away from the previous site but in the same general area, and never reuse or share needles, syringes, cartridges, or pens. If you forget a dose, follow the directions your doctor gave you when you first started: ask your doctor what to do if you forget to inject a dose at the correct time and write those directions down so you can refer to them later. For storage, keep the medication in the container it came in and out of reach of children, store unopened human insulin in the refrigerator and never allow it to freeze — do not use insulin that has been frozen and thawed — and if a refrigerator is unavailable, such as on vacation, store it at room temperature away from direct sunlight and extreme heat; how long it can be kept at room temperature, and how long you may keep a pen or dosing device after first use, depends on the product, so check the manufacturer's information.

Source: MedlinePlus — Human Insulin Injection

Part D formulary coverage

Source: CMS Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files — Monthly file 2026-10-15 (plan year 2027), file 2027_20261008.zip (data.cms.gov dataset ed1496ea-23e7-41f1-9292-172fa842ccfb): basic drugs formulary file + plan information file, both dated 20261031 inside the zip; downloaded and aggregated 2026-10-30. Medication RxCUI sets resolved through the NLM RxNav (RxNorm) API.

What you pay

Without insurance, the cash benchmark is $4.2557 per unit (HUMULIN 70-30 VIAL) — about $127.67 for 30 units. NADAC benchmark — the average price pharmacies pay (CMS, as of 2026-11-04). Pharmacy shelf prices vary.

A tier is not a price; what you pay depends on your plan, pharmacy, and benefit stage; Extra Help or Medicaid can lower it further.

Sources: CMS Plan Benefit Package + formulary data; CMS NADAC · Checked 2026-11-08

Coverage by plan and tier

Of the 5,495 Medicare drug plans we track for 2027, 5,495 list Insulin 70/30 mix — NPH/isophane + regular (Humulin 70/30, Novolin 70/30) — 100% of plans. Most of those plans put it on Tier 3: 4,892 plans, 89.0% of the plans that list it. Other plans place it on Tier 2 (409 plans), Tier 1 (129 plans) or Tier 6 (55 plans). For example: Aetna Medicare Dual Extra (HMO D-SNP) puts it on Tier 3; Aetna Medicare Dual Extra Care (PPO D-SNP) puts it on Tier 3; Aetna Medicare Value Plus (PPO) puts it on Tier 3. You can compare these plans side by side on our Medicare Advantage hub. A tier is not a price. What you pay also depends on whether you have met your plan's deductible, whether the drug costs a flat copay or a share of the price, and whether you get Extra Help or Medicaid.

Read next

• Part D in 2027: The $700 Deductible, the $2,400 Cap, and the $35 Insulin Rule
• Extra Help in 2027: Lower Drug Copays and Who Qualifies
• Checking Medicare Savings Programs and Extra Help

Part D spending averages (2024)

Source: CMS Medicare Part D Spending by Drug (Drug Spending Dashboard), release RY26 P04 V10, data through 2024 (DSD_PTD_RY26_P04_V10_DY24_BGM.csv), downloaded 2026-10-30

Companies covering this drug

Part D and Medicare Advantage plan sponsors that list this drug on a formulary, 50 at a time.