FDA Rarely Tests Generic Drugs: What ProPublica’s 2025 Investigation

• 90% of U.S. prescriptions are affordable generics, but the FDA rarely tests them post-approval for quality or effectiveness.
• ProPublica (2025) found the agency relies on manufacturers' self-testing, especially for overseas-made drugs (India/China).
• Independent Valisure lab tests revealed issues: some bupropion and metoprolol generics dissolved improperly, potentially reducing effectiveness; tacrolimus variants dissolved too fast, risking side effects.
• Most drugs still pass FDA standards, but quality can vary between manufacturers.

Nine out of ten prescriptions filled in the U.S. are generics. These medications save billions each year and make treatment more affordable for millions of patients.

We tend to trust that they work just as well as brand names, and most of the time, they do. But how does the FDA actually make sure of that?

How the FDA Oversees Generics

The FDA’s "Orange Book" serves as the gold standard for drug equivalence. To get approved, a generic manufacturer must prove bioequivalence. This means the drug must:

• Contain the same active ingredient
• Work in the body with the same strength and dosage
• Be delivered in the same way (e.g., a pill vs. an injection)

That determination (bioequivalence) is based on data submitted by the manufacturer. Once approved, manufacturers are expected to monitor quality, maintain proper manufacturing processes, and notify the FDA if problems arise.

What many people don’t realize is that, after approval, the FDA rarely re-tests generic drugs already being sold. Instead, it primarily relies on companies’ self-reporting and occasional inspections.

What ProPublica Found

A recent investigative series by ProPublica, in partnership with the independent lab Valisure, questioned how consistent generic quality remains once drugs hit pharmacy shelves.

Much of America’s generic drug supply is made overseas in countries like India and China, where FDA inspections can be infrequent. This can make it hard to track whether all versions perform as expected.

When ProPublica and Valisure independently tested several commonly used generics, they found that most met expected standards. But some did not.

Case Examples

Bupropion (antidepressant)

• One generic version dissolved more slowly than the brand drug. Slow dissolving can reduce the amount of medicine absorbed over time.
• FDA records showed only a handful of tests done in recent years, with some years showing no testing at all.
• A previous generic version from Teva was pulled from the market years earlier for not performing like the brand name. Other manufacturers, including Sun Pharma, have issued multiple recalls due to dissolving issues.

Metoprolol Succinate (for blood pressure and heart failure)

• A generic sample released medication much more slowly than the brand over six hours, which could affect how well it controls blood pressure or heart symptoms.
• Dozens of companies sell metoprolol in the U.S., yet post-market FDA testing remains limited.
• Only a small number of samples were tested over several years.

Tacrolimus (immunosuppressant for transplant patients)

• An independent lab found one generic dissolved too quickly, increasing side effect risks such as tremors or kidney issues.
• In 2023, the FDA stated this version might not work the same as the brand, but it remained available for prescribing.

Manufacturing Concerns and Overseas Inspections

In several cases, FDA inspectors found serious issues at overseas factories. Violations included manipulated records and repeated quality failures.

Some facilities were restricted from shipping new products to the U.S. But drugs already on the market were sometimes allowed to stay to avoid shortages.

According to investigators, testing of these affected drugs remained limited.

How Europe Does It Differently

In Europe, regulators take a stricter approach: every batch must be tested in a certified lab before it’s released. The U.S. has no similar blanket rule.

Since 2018, FDA data show fewer than 650 total drug samples tested under its surveillance program, including both brand and generic drugs. Most passed, but that number is small compared to the thousands of products in circulation.

What It Means for Patients

The investigation doesn’t suggest that most generics fail. In fact, generics remain essential, cost-saving, and FDA-approved.

But it does raise questions about whether post-market oversight goes far enough to ensure ongoing consistency, especially for drugs made overseas or produced by multiple manufacturers.

If a medication feels different or less effective after a refill, speak with your pharmacist or prescriber. They can help confirm if a switch to a different generic or back to the brand may make a difference.