How to Compare Manufacturer Expiration Dates vs. Pharmacy Beyond-Use Dates for Medications

When you pick up a prescription, you might see two different dates on the bottle: one printed by the drugmaker, and another written by the pharmacist. One says expiration date. The other says beyond-use date. They look similar, but they’re not the same. Using the wrong one could mean taking a drug that’s lost its strength-or worse, one that’s unsafe.

What an Expiration Date Really Means

The expiration date on your pill bottle comes from the manufacturer. It’s not a guess. It’s the result of months, sometimes years, of lab testing. The company puts the medicine under extreme conditions-heat, humidity, light-to see how long it stays stable. The FDA requires this testing for every approved drug sold in the U.S. since 1979.

This date guarantees the drug will still have at least 90% of its labeled potency until that day. It also ensures the medicine won’t break down into harmful substances. That guarantee only applies if the drug stays in its original, unopened container, stored as directed-usually at room temperature, away from moisture.

For example, a bottle of amoxicillin might say "Exp. 06/2025." That means the manufacturer stands behind its effectiveness and safety until June 2025, as long as you haven’t opened it or stored it in a hot bathroom. Even after opening, the expiration date still holds. You don’t get extra time just because you haven’t finished the bottle.

What a Beyond-Use Date Is (And Why It’s Shorter)

Now, imagine your doctor prescribes a medication that isn’t made by a big drug company. Maybe you’re allergic to the dye in the commercial version. Or you need a liquid form of a pill. Or you’re a child who can’t swallow tablets. That’s where compounding pharmacies come in.

These pharmacies mix ingredients to create custom medicines. When they do, they can’t use the original manufacturer’s expiration date. Why? Because they changed the formula. They added water. They crushed pills. They mixed powders. That changes how the drug behaves.

So the pharmacist gives you a beyond-use date-or BUD. This isn’t a marketing claim. It’s a safety limit based on USP (United States Pharmacopeia) guidelines. The BUD tells you the last day the compounded medicine is likely safe and effective.

Here’s the catch: BUDs are almost always shorter than expiration dates. Why? Because compounded medicines lack the preservatives, stabilizers, and controlled manufacturing of commercial drugs. They’re more fragile. A liquid antibiotic made in the pharmacy might have a BUD of just 14 days-even if the original powder had a 5-year expiration. A pill made by mixing two powders might last 30 days at room temperature. A sterile IV bag? Maybe 48 hours.

When the Two Dates Collide

Sometimes, you’ll get a commercial drug that’s been repackaged. Maybe your pharmacy took 100 pills from a big bottle and put them into a child-friendly blister pack. That’s still considered an alteration. So now, instead of the original expiration date, you get a BUD.

USP rules say the BUD for repackaged drugs can’t be longer than:

• The original manufacturer’s expiration date, or
• One year from the day the pharmacy repackaged it

Whichever comes first. So if your 100-pill bottle of metformin expires in 2027, but the pharmacy repackages it in January 2026, your new BUD is January 2027. Not 2028. Not 2030. January 2027.

That’s why you should always check both dates when you get medication. If the pharmacist gave you a new bottle with a handwritten date, that’s your BUD. Ignore the original date on the big bottle from the manufacturer.

Storage Matters More Than You Think

Expiration dates assume ideal storage. But how many of us keep meds in a bathroom cabinet? Or next to the coffee maker? Heat and moisture destroy drugs faster.

With compounded medicines, storage is even more critical. A pill that was stable at room temperature might need refrigeration once it’s mixed with liquid. A cream might separate if left in the sun. The pharmacist should tell you how to store it-but they don’t always do it clearly.

One patient in Adelaide told me their compounded thyroid medication came with a BUD of 6 months. But the original bottle said 2025. They thought they were fine until the 6-month mark. Then they found out the pharmacist had changed the formula. The medicine had to be kept cold. They didn’t refrigerate it. Half the dose was gone by month three. They had to pay $120 for a new batch.

Bottom line: if the BUD says "refrigerate," put it in the fridge. Even if the original drug didn’t need it. The pharmacy changed it. So the rules changed too.

Why BUDs Lead to Waste-and Higher Costs

Compounded medications are expensive. They cost 2 to 5 times more than the commercial version. Why? Because they’re made one at a time. No automation. No bulk pricing.

And because BUDs are short, patients often throw away unused medicine. A 2022 survey found 68% of people on compounded drugs threw some away before finishing their course. Only 22% did that with regular prescriptions.

Imagine you’re on a 90-day course of a compounded hormone cream. The BUD is 60 days. You can’t refill early. You can’t store extra. You have to get a new batch after two months-even if you only used half. That’s not just inconvenient. It’s costly.

Some pharmacists are trying to fix this. They’re pushing for longer BUDs for low-risk compounds. But regulators are moving the other way. The USP is tightening rules. Proposed changes could cut maximum BUDs by up to 30% for certain formulations. Safety first. But waste increases.

What Happens If You Use Expired or Overdue Medicine?

You might hear stories: "My aspirin was 10 years past its date. Still worked fine." That’s true-for some drugs, under perfect storage. The FDA tested over 100 medications and found 90% still had at least 90% potency 15 years past expiration.

But here’s the problem: you don’t know how your medicine was stored. Was it in a hot car? A damp basement? A sunny windowsill? The manufacturer’s testing didn’t account for that. That’s why the FDA says: don’t use expired drugs.

For compounded meds, the risk is higher. No preservatives. No controlled environment. Bacteria can grow. Chemicals can break down. A liquid antibiotic past its BUD might not kill infection. Worse-it might make you sick.

There’s no benefit to stretching either date. If it’s expired or past its BUD, it’s not worth the risk.

What to Do When Your Medicine Expires

Don’t flush it. Don’t toss it in the trash. Don’t give it to a friend.

Most U.S. pharmacies offer free take-back programs. Ninety-two percent of them do, according to the National Community Pharmacists Association. Walk in with your old pills, creams, or liquids. They’ll dispose of them safely.

If your pharmacy doesn’t have a program, check with your local health department. Some cities have drop-off locations at police stations or community centers.

And next time you get a prescription, ask: "Is this a compounded medication? What’s the beyond-use date? How should I store it?" If they can’t answer clearly, ask for the pharmacist. You’re entitled to that information.

Key Takeaways

• Expiration dates are set by manufacturers and apply to unaltered, FDA-approved drugs.
• Beyond-use dates are set by pharmacists for compounded or repackaged medicines and are usually much shorter.
• Never use a compounded medicine past its BUD-even if the original bottle says it’s good for years.
• Storage conditions matter more for compounded drugs. Refrigerate if told to.
• Expired or overdue meds may not work-and could be dangerous.
• Always return old or expired medication to a pharmacy for safe disposal.

Frequently Asked Questions