Humulin and Novolin are not the same product, but they contain the same type of insulin. Both are recombinant human insulin, meaning they are lab-made copies of the insulin your body naturally produces. The key difference is that Humulin is made by Eli Lilly and Company, while Novolin is made by Novo Nordisk. They come in matching formulations, work on nearly identical timelines in your body, and serve the same purpose, but they are manufactured using different processes and are not officially interchangeable without a prescription change.
Same Insulin, Different Manufacturers
Both brands use genetic engineering to produce human insulin, but the organisms doing the work are different. Eli Lilly makes Humulin using E. coli bacteria, a method that earned FDA approval in 1982 as one of the first recombinant DNA drugs ever sold. Novo Nordisk makes Novolin using baker’s yeast (Saccharomyces cerevisiae), and that product received approval in 1991.
The end result in both cases is human insulin identical in structure to what a healthy pancreas releases. The different production organisms don’t change the final insulin molecule, but they do mean the two products go through separate manufacturing, purification, and quality control processes. This is why the FDA treats them as distinct licensed biologics rather than copies of each other.
Matching Formulations
Both brands offer the same three core formulations, and each pair works on roughly the same schedule:
- Regular (R): Humulin R and Novolin R are short-acting insulins. They start working within 30 to 60 minutes, peak at 2 to 4 hours, and last 5 to 8 hours. You typically inject these before meals.
- NPH (N): Humulin N and Novolin N are intermediate-acting insulins. They kick in within 1 to 1.5 hours, peak between 6 and 10 hours, and can last 14 to 24 hours. These provide background insulin coverage throughout the day or overnight.
- 70/30 Mix: Humulin 70/30 and Novolin 70/30 both combine 70% NPH insulin with 30% regular insulin in a single vial. This gives you both a background level and a mealtime boost in one injection.
One product that doesn’t have a Novolin equivalent is Humulin R U-500, a concentrated version of regular insulin (five times the standard strength) designed for people who need very large doses.
Why You Can’t Just Swap Them
Despite containing the same type of insulin, the FDA does not classify Humulin and Novolin as interchangeable. Both are licensed under Section 351(a) of the Public Health Service Act as standalone biologics. Neither is classified as a biosimilar to the other. In practical terms, this means your pharmacist cannot substitute one for the other the way they might swap a brand-name pill for its generic. Switching from Humulin to Novolin, or the reverse, requires a new prescription from your provider.
That said, many doctors do switch patients between the two when cost, insurance coverage, or availability makes one a better option. The adjustment is usually straightforward because the onset, peak, and duration profiles are so similar. Your provider may want to monitor your blood sugar more closely for a short period after a switch, since small differences in how your body responds are always possible.
Price Differences
Cost is one of the biggest practical reasons people compare these two brands. Novolin products tend to be easier to find at a lower out-of-pocket price, largely because of Walmart’s long-running deal with Novo Nordisk. Walmart sells Novolin N, Novolin R, and Novolin 70/30 under its ReliOn store brand for $25 per vial or $44 for a box of five pens. No prescription is needed in many states for these over-the-counter human insulin products, though laws vary.
Humulin doesn’t have an equivalent flat-rate retail program, but Eli Lilly offers a cap of $35 per month for people paying cash or using commercial insurance through its savings programs. Depending on how many vials you use per month, one deal may be significantly cheaper than the other. If you use two or three vials monthly, the per-vial Walmart pricing on Novolin could save you money compared to the monthly Lilly cap, or vice versa.
Which One Should You Use?
For most people, the choice between Humulin and Novolin comes down to insurance formulary coverage, price, and what your pharmacy stocks. The clinical performance is close enough that either brand will manage blood sugar effectively when dosed correctly. If your insurance covers one but not the other, that’s usually the deciding factor.
If you’re paying out of pocket and looking for the lowest possible price, Novolin from Walmart is hard to beat at $25 a vial. If you’re already stable on one brand and your supply is consistent, there’s no medical reason to switch. The important thing is using whichever human insulin you and your provider have chosen consistently, at the right doses, and on schedule.