Biosimilar or Generic? How to Choose the Right Medication for Your Treatment

When your doctor talks about switching from a brand-name drug to a cheaper version, you might hear the words generic or biosimilar-but they’re not the same thing. One is a chemical copy, the other is a biological copy. And confusing them could mean missing out on savings-or worse, making a choice that doesn’t fit your treatment plan.

What’s the real difference between generics and biosimilars?

Generics are exact chemical copies of brand-name drugs. Think of them like photocopies of a simple blueprint. If you take a generic version of atorvastatin (the drug in Lipitor), you’re getting the same molecule, in the same dose, with the same effect as the original. The FDA requires generics to match the brand-name drug in strength, dosage, and how your body absorbs it. That’s why millions of people use generics every day for high blood pressure, cholesterol, or thyroid issues-without noticing a difference.

Biosimilars are different. They’re not copies. They’re highly similar versions of complex biologic drugs made from living cells-like proteins, antibodies, or enzymes. These drugs, such as Humira or Herceptin, are used for conditions like rheumatoid arthritis, Crohn’s disease, or certain cancers. Because they’re made by living organisms (not chemically synthesized), even tiny changes in the manufacturing process can affect their structure. That’s why biosimilars aren’t identical to the original-they’re so close that they work the same way in your body, but they can’t be called exact replicas.

Why does this matter for your treatment?

Cost is the biggest reason both exist. Generics cut prices by 80-85% compared to brand-name drugs. A 30-day supply of generic lisinopril might cost $4 instead of $200. Biosimilars don’t save as much-typically 15-20% off the original biologic-but that’s still huge when the original costs $10,000 a year. For someone on a biologic for psoriasis or multiple sclerosis, that 20% could mean the difference between affording treatment or skipping doses.

But here’s the catch: you can’t swap a biosimilar for a generic. They’re not interchangeable. You can’t take a generic version of Humira because it doesn’t exist. Humira is a biologic. Only a biosimilar can replace it. And even then, not all biosimilars are approved for automatic substitution at the pharmacy. Only those labeled “interchangeable” can be switched without your doctor’s permission-and even then, some states require your prescriber to be notified.

How do you know which one you’re getting?

Check the name. Generic drugs usually have the same name as the brand, just without the trademark. For example, metformin is the generic for Glucophage. Biosimilars have longer, more complex names that include a four-letter suffix to tell them apart. For example, the biosimilar for Humira is adalimumab-atto. That suffix is required by the FDA to track safety and side effects.

Look at the form. Generics often come in pills or capsules. Biosimilars are almost always injected or infused-because they’re proteins, your body can’t absorb them orally. You’ll see them as pre-filled pens, syringes, or IV bags. If you’re switching from one biologic to a biosimilar, you might get a different delivery device. Some patients report confusion when the pen looks different, even if the dose is the same.

Are biosimilars safe? What does the data say?

Yes, they’re safe. The FDA approves biosimilars only after reviewing thousands of pages of data: lab tests, animal studies, and clinical trials involving thousands of patients. A 2022 review of 128 studies on biosimilar infliximab (used for Crohn’s and arthritis) found no meaningful difference in safety or effectiveness compared to the original. In fact, the rate of serious side effects was nearly identical.

One concern is immunogenicity-your body reacting to the drug as if it’s foreign. This can cause rashes, fatigue, or even reduce the drug’s effectiveness. But studies show this risk is no higher with biosimilars than with the original biologics. The FDA’s adverse event database shows biosimilar infliximab had 0.12 adverse events per 100 patient-years; the original had 0.15. That’s not a meaningful difference.

Real-world stories back this up. A patient with rheumatoid arthritis in Bristol switched to an adalimumab biosimilar and saved over $8,000 a year-without a flare-up. A colon cancer patient on bevacizumab saw her out-of-pocket cost drop from $450 to $75 per infusion. Her tumor markers stayed stable.

When should you avoid switching?

There are rare cases where switching might not be ideal. If you’re on a drug with a narrow therapeutic index-where even small changes in blood levels can cause harm-your doctor may prefer to stick with the original. But even here, data shows biosimilars are safe. For example, insulin biosimilars like Semglee are now approved as interchangeable, meaning pharmacists can swap them without asking your doctor.

Some patients feel anxious about switching. A 2022 survey found 42% of people with psoriasis worried biosimilars wouldn’t work as well. That’s understandable. But education helps. When your doctor explains the science-how the drug is made, how it’s tested, and why it’s safe-patients feel more confident. Many who were nervous at first end up reporting the same results.

What about cost and insurance?

Generics are almost always covered with low copays. Most insurance plans put them in the lowest tier. Biosimilars are trickier. Some insurers still favor the original biologic because of contracts with manufacturers. Others push biosimilars to save money. Check your formulary. Ask your pharmacist: “Is there a biosimilar for my drug? Is it covered?”

Many biosimilar manufacturers offer patient support programs-like Amgen’s SupportPlus-that help with copay assistance, insurance navigation, and even training on how to use the injection device. These don’t exist for generics, because generics are cheap and simple.

And here’s something new: the Inflation Reduction Act of 2022 removed a financial penalty for doctors who prescribe biosimilars in Medicare Part B. That means more providers are now willing to switch patients, because they’re not losing money on it.

What’s the future?

Biosimilars are growing fast. In 2023, the global market hit $12.4 billion-and it’s expected to reach $58.7 billion by 2030. In Europe, biosimilars make up 65% of the market for drugs they’re approved to replace. In the U.S., it’s only 35%, but that’s climbing. By 2027, nearly half of all biologic prescriptions in the U.S. could be biosimilars.

More approvals are coming. The first interchangeable biosimilar for Stelara (ustekinumab) is expected in 2024. That’s a blockbuster drug with $5 billion in annual sales. If it gets replaced by a biosimilar, patients could save billions.

Meanwhile, generics continue to dominate. Over 11,000 are approved in the U.S. They’re the backbone of affordable care for conditions like diabetes, depression, and infections.

What should you do next?

If you’re on a brand-name drug and wondering if you can switch:

1. Ask your doctor: “Is there a generic or biosimilar version of this drug?”
2. Check the drug’s name. If it’s a small molecule (pill), it’s likely a generic candidate. If it’s injected and used for autoimmune or cancer conditions, it’s probably a biologic-and a biosimilar may be available.
3. Call your pharmacy. Ask if they have a biosimilar or generic on hand, and what your out-of-pocket cost would be.
4. Don’t assume switching is risky. The science says it’s safe. The data says it works.
5. If you’re nervous, ask for a patient education resource. Many manufacturers offer free videos, brochures, or one-on-one counseling.

There’s no one-size-fits-all answer. But if you’re paying hundreds or thousands a month for a medication, it’s worth asking. You might be eligible for a cheaper, equally effective option.

Bottom line: Choose based on your drug, not your fear

Generics are for pills. Biosimilars are for injections. One isn’t better than the other-they’re just different tools for different jobs. If you’re on a biologic, a biosimilar could save you thousands. If you’re on a pill, a generic is almost always the smartest choice. Talk to your doctor. Ask your pharmacist. Look up your drug in the FDA’s Purple Book (for biosimilars) or Orange Book (for generics). You don’t have to accept a high price tag if there’s a safe, approved, cheaper option waiting.