By WPG Research Team • Published May 6, 2026 • Last verified July 14, 2026

How Long Does GLP-1 Last After Opening?

Your answer depends on the exact pen, syringe, or vial in your hand — not the brand name alone. Here’s the complete, device-by-device breakdown, plus an interactive calculator that gives you your personal throw-it-out date.

Quick answer: discard windows at a glance

* 30 days from first use, 30 total days at room temperature, or 4 weekly doses — whichever comes first.

Discard-by date calculator

Enter your drug, device, and first-use date. The tool applies the four-path framework below and gives you a personal discard date — no email, no account, everything stays in your browser.

First: figure out which of four things you have

Almost every question on this page collapses into one of four handling paths. Know which one is yours before you read further.

Why does every website give a different number?

Answer in one line: Most conflicting answers mash together four different clocks — time after first use, time after first puncture, time out of the fridge before use, and single-dose disposal — and many older articles were written before newer devices like the Zepbound KwikPen, the Wegovy FlexTouch, and Ozempic single-dose syringes existed. The number you saw wasn’t always wrong; it may just not be about your device.

Three things cause almost all the confusion.

“28 days” is not a GLP-1 rule. It’s a general safety default for punctured multi-dose vials. Public health guidance from the CDC, based on the USP standard pharmacies follow, says: once you puncture a multi-dose vial, use it within 28 days unless the product says otherwise — and don’t save leftovers from a single-dose vial at all. Plenty of GLP-1 pens do say otherwise. Ozempic multi-dose pens say 56 days. So “everything expires in 28 days” is a myth. It’s a default discard period for one type of container, not a rule for the whole class.

The same brand can come in more than one device now. This trips up even good writers. Here’s the current lay of the land:

If an article says flatly “Wegovy lasts 28 days,” it’s answering for only one version. The real question is: do you have a device you use once, or a device you use for a month?

People keep asking because it feels wasteful — and that’s fair. Spend a few minutes in any GLP-1 forum and you’ll see the same frustration on repeat, especially from folks using compounded vials: the label says discard after 28 days, but there’s clearly a lot of medicine left, and tossing it feels like pouring money down the drain. That instinct is completely reasonable. But — and this is the part that matters — the amount of liquid you can see doesn’t tell you whether the medicine is still strong or still sterile. We’ll come back to that, because it’s the single most important idea on this page.

What even counts as “opening” a GLP-1?

Answer in one line: “Opening” isn’t one event across GLP-1 products. A multi-dose pen usually starts its clock at first use, a multi-dose vial usually starts at first needle puncture, and a single-dose device has no after-opening clock because it’s discarded after one shot.

Multi-dose pen (Ozempic, Saxenda, Victoza, KwikPens): the clock starts at first use — your first injection from that device. In normal use, mark the date of that first shot. And here’s a common trap: putting the pen back in the fridge does not reset that clock. Refrigerating an in-use Ozempic pen at week two doesn’t buy you a fresh 56 days. The countdown keeps running.

Multi-dose vial (compounded, or a brand multi-dose vial): the practical starting point is usually the first puncture — the first time a needle goes in. That’s when the sterile seal is broken and the discard window your pharmacy set starts to matter.

Single-dose pen, syringe, or vial (most Wegovy, Ozempic syringes, single-dose Mounjaro/Zepbound, Trulicity): there’s no ongoing “opened” period. It’s built for one shot, then the sharps bin. If you’re looking at a single-dose device wondering how many more days you can stretch it, the answer is zero — it was one dose. (CDC is blunt about single-dose vials specifically: don’t save what’s left for later, even for yourself.)

Pill bottles (Rybelsus, Ozempic tablets, Wegovy tablets, Foundayo): no “28 days after you open the bottle” clock. You go by the printed expiration, keep the tablets in their original bottle, keep them dry, and close the cap.

How long do Ozempic and Wegovy last after opening?

Answer in one line: Ozempic multi-dose pens last 56 days after your first injection, while Ozempic single-dose syringes are used once (with a 28-day pre-use room-temperature allowance). Most Wegovy is single-dose — you use it once and discard it — but a multi-dose Wegovy FlexTouch pen also exists and is discarded 56 days after first use.

Ozempic multi-dose pen — 56 days after first use

Once you take your first dose, per Novo Nordisk’s prescribing information you can keep the pen in the fridge or at room temperature (up to 86°F) and use it for 56 days. After that, toss it — even if there’s still medicine in the window. Keep the cap on between doses, and take the needle off after each shot.

Ozempic single-dose prefilled syringe — use once

The current Ozempic label also includes single-dose prefilled syringes (0.25, 0.5, and 1 mg). These are one-and-done: use it, then discard it. Before use, an unused syringe can sit at 46–86°F for up to 28 days if needed.

Wegovy single-dose — use once, then discard

This is what most Wegovy users have: one pen per weekly dose. Each single-dose pen is for one-time use. The 28-day number you’ll see is different. It’s how long an unused pen (or single-dose syringe, or the HD pen) can sit out of the fridge — between 46°F and 86°F, in its carton — before you remove the cap. It’s a before-use allowance, not a keep-using-it window.

Wegovy FlexTouch multi-dose pen — 56 days after first use

There’s also a multi-dose Wegovy pen (the FlexTouch) that holds four weekly 2.4-mg doses in one device. If yours is a pen you use across a month rather than one-and-done, discard it 56 days after your first dose, kept in the fridge or at room temperature. This is the exact spot where a generic “Wegovy = 28 days” answer sends people wrong.

How long do Mounjaro and Zepbound last after opening?

Answer in one line: Single-dose Mounjaro and Zepbound pens and vials are used once and discarded, with up to 21 total days out of the fridge allowed before use. Their multi-dose vials and KwikPens follow a “whichever comes first” rule: 30 days after first use, 30 total days at room temperature, or 4 weekly doses.

Single-dose Mounjaro or Zepbound (pen or vial)

One shot, then discard. An unused single-dose device can sit at room temperature (up to 86°F) for up to a total of 21 days before you use it; once that cumulative total hits 21 days, discard it. There’s no ongoing after-opening window, because there’s only one dose.

Multi-dose Mounjaro or Zepbound (vial or KwikPen) — the 30 / 30 / 4 rule

Discard when the first of these three things happens:

• 30 days have passed since your first use, or
• 30 total days at room temperature have added up (you can move it between fridge and counter — the room-temperature days just can’t total more than 30), or
• You’ve taken 4 weekly doses.

Whichever hits first wins. In real life, that usually means you finish four weekly shots and discard the device even if a little medicine is left.

What about Trulicity, Saxenda, Victoza, and the older shots?

Answer in one line: Trulicity is single-dose (used once, with a 14-day pre-use room-temperature allowance). Saxenda and Victoza are multi-dose pens discarded 30 days after first use. Byetta is a multi-dose pen with a stricter 77°F ceiling, and Bydureon BCise is single-dose and is supposed to look cloudy after mixing.

Trulicity (dulaglutide) — single-dose

One pen, one shot, discard. An unused pen can stay at room temperature for up to a total of 14 days before use — the shortest room-temperature duration in this group, so it’s the one to be most mindful about leaving out.

Saxenda (liraglutide) — 30 days after first use

This is a daily multi-dose pen, so you’ll use it more often than the weekly shots. Once you start it, use it within 30 days, kept in the fridge or at room temperature (up to 86°F).

Victoza (liraglutide) — 30 days after first use

Same 30-day window as Saxenda once you open it.

Byetta (exenatide) — 30 days, and stricter on heat

After first use, Byetta follows a 30-day window, and its ceiling is lower than the newer shots: no warmer than 77°F. If you have an older exenatide product, confirm the exact rule on your own label.

Bydureon BCise (exenatide extended-release) — single-dose, and cloudy is normal

This one is used once, with up to 4 weeks out of the fridge before use. The important thing to know: after you mix it, Bydureon BCise is supposed to look cloudy, opaque white to off-white. For this specific product, cloudy doesn’t mean bad — follow its Instructions for Use.

If your medication isn’t in this list at all, that’s your cue to read the Instructions for Use in the box, or call the pharmacy that filled it. Don’t borrow another drug’s rule.

How long do GLP-1 pills last after opening?

Answer in one line: Oral GLP-1 medications — Rybelsus, Ozempic tablets, Wegovy tablets, and Foundayo — don’t carry a separate “28 days after you open the bottle” countdown. Follow the printed expiration date and keep the tablets in their original, closed bottle, protected from moisture (and, for Foundayo, from light in its original carton).

Pills are the easy ones. No fridge, no injection clock. Store oral GLP-1 tablets at room temperature, keep them in the original bottle they came in (the bottle helps protect them from moisture), and close the cap after each use. Foundayo also calls for keeping it in its original light-protective carton. There’s no “use within X days of opening the bottle” — you simply use them by the expiration date on the label. Don’t move them into a pill organizer or another container, since that can let moisture in.

How long does compounded semaglutide or tirzepatide last after opening?

Answer in one line: There is no universal after-opening date for compounded semaglutide or tirzepatide. The dispensing pharmacy’s label controls it — the Beyond-Use Date plus any separate “discard after first puncture” or single-use instruction — and when both apply, the earlier date wins. When the label is missing or unclear, call that pharmacy before using the vial.

First, what “compounded” means: it’s semaglutide or tirzepatide prepared to order by a licensed compounder, rather than a sealed product supplied under an FDA-approved manufacturer label. Compounded drugs are not FDA-approved. The FDA does not review them for safety, effectiveness, or quality before they’re sold, and their strength and instructions can vary. That’s not a scare tactic — it’s just why you can’t take Ozempic’s 56-day rule and stamp it on a compounded vial. Different product, different rules.

The number that counts is your pharmacy’s label. A Beyond-Use Date (BUD) is the discard date your compounder assigns and prints on your vial. It’s different from a manufacturer’s expiration date. Don’t apply a blanket 28-day rule, and don’t borrow a number from a forum — your vial’s BUD, and any separate post-puncture instruction, is your answer.

Why you might see two dates. Many compounders add a shorter “use within X days of first puncture” instruction on top of the overall BUD. The reason is sterility, not strength: puncturing the vial breaks the sterile seal. So you can end up with two dates — a longer BUD and a shorter after-puncture window — and the earlier one wins.

What to read on your pharmacy label (photograph it if it helps):

• Your name and your prescriber
• The pharmacy's name and phone number
• The drug and its concentration in mg/mL
• Total volume in the vial
• Storage temperature
• The Beyond-Use Date
• Any "discard after first puncture" or single-use instruction
• A lot or prescription number

If the label only gives a BUD, call the pharmacy and ask one question: “Does this vial also have a discard window after the first puncture, and does that replace the printed BUD or run inside it?” That single question clears up most of the confusion.

We know the frustrating part is watching medicine go in the sharps bin. But no honest page can tell you to stretch a compounded vial past its labeled date just because other people online say they do, or because there’s liquid left. Borrowing a longer window from a different product would give you false confidence about strength and sterility you can’t actually check.

Does GLP-1 need to stay in the fridge after opening?

Answer in one line: Some multi-dose GLP-1 pens can stay in the fridge or sit at room temperature (within their labeled range) after first use, while single-dose devices are discarded after one shot. Refrigerating an opened pen does not extend or restart its labeled 30- or 56-day window.

Can you keep it out of the fridge once it’s open?

For most multi-dose brand pens — Ozempic, Saxenda, Victoza, the KwikPens — yes, within their labeled window and as long as it stays inside the product’s temperature range (86°F for most). A lot of people prefer room temperature because a cold shot can sting. Just keep the pen in a stable spot, out of direct sun, away from radiators and hot cars.

Does putting it back in the fridge buy you more time?

No. This is the myth worth repeating: refrigerating an in-use pen does not reset the clock. Your Ozempic pen doesn’t get a fresh 56 days because you chilled it again. Once the countdown starts at first use, it runs wherever you store it.

For the single-dose and cumulative-time products (single-dose Mounjaro/Zepbound, Trulicity, and the multi-dose Mounjaro/Zepbound devices), track your total time out of the fridge, since that time adds up and counts against you.

Where in the fridge? Original carton, middle shelf, away from the very back wall and the cooling vents (that’s where things accidentally freeze), and not touching an ice pack. A cheap fridge thermometer settles a lot of arguments — aim for 36°F to 46°F.

Can you still use a GLP-1 after 28 days if there’s medicine left?

Answer in one line: Sometimes yes — but only when your specific product allows a longer window, like Ozempic’s 56 days. You should not stretch a 28-day pharmacy instruction just because another brand lasts longer, or because liquid remains, since the amount you can see doesn’t prove the medicine is still strong or sterile.

This is the emotional core of the whole topic, so let’s hit it straight.

When 28 days is NOT your limit: if you have an Ozempic multi-dose pen (56 days), or a Saxenda/Victoza pen (30 days), the “28-day” number simply isn’t yours. Use your product’s actual window.

When 28 days IS the limit: if your compounded pharmacy label says discard 28 days after first puncture, that’s your rule — even if the vial looks half full. It’s set for sterility, and another product’s longer window doesn’t apply to your vial.

Why the leftover medicine doesn’t change the date. Three different things get tangled here, and separating them clears it up:

• How much is left — that’s just volume. It tells you nothing about whether the medicine works.
• Whether it’s still strong — past the labeled date, no one can promise it’s still full-strength.
• Whether it’s still sterile — once a needle has punctured a vial, keeping it past its window raises the risk.

The liquid in the window answers only the first one. The date on the label is doing the other two jobs — and you can’t judge either by looking. That’s why “but there’s so much left” isn’t a reason to keep using it past the labeled date.

If you’re regularly finishing your window with a lot of medicine left, that’s worth a conversation with your prescriber or pharmacy about concentration and dose — not a reason to guess on your own.

What if it was left out, got hot, froze, or arrived warm?

Answer in one line: A short time at room temperature may still fall inside your product’s allowance, but freezing, excessive heat, warm shipments, and unknown storage histories call for caution. The FDA specifically recommends not using injectable GLP-1 medication that arrives warm or without proper refrigeration until the issue is sorted out.

Run through these before you inject.

How can you tell if your GLP-1 has gone bad?

Answer in one line: For products meant to be clear, cloudiness, unexpected color, floating particles, cracks, or leaks are reasons to stop and contact the pharmacy. A normal-looking solution does not prove the medicine is still potent, sterile, or safely stored — appearance can’t tell you those things.

Look before every dose. For the products that are supposed to be clear solutions (Ozempic, Wegovy, Mounjaro, Zepbound, and most others), these are stop signs:

• Cloudy when it should be clear
• An off or unexpected color (most are clear and colorless; Zepbound and Mounjaro can be colorless to slightly yellow — know your normal)
• Particles, flakes, or crystals
• A cracked device, a leak, or a broken seal
• A missing or unreadable label

And please don’t judge potency by your appetite. A weaker week, a plateau, more “food noise” — those happen for lots of reasons and don’t reliably mean your vial went bad. Do not bump your own dose to compensate. The FDA has reported real dosing errors with compounded semaglutide, including people confusing milligrams, milliliters, and “units,” partly because concentrations vary. If the medicine feels off, talk to your prescriber — don’t improvise the math.

How do you throw away an old GLP-1 pen, syringe, or vial?

Answer in one line: Put used needles, syringes, and needle-containing pen devices into an FDA-cleared sharps container (or a sturdy, sealable heavy-duty plastic container where local rules allow). Use a drug take-back option for leftover medicine when one is available, and never toss loose needles into household trash or recycling.

We’ve said “throw it out” a lot on this page, so here’s how to actually do it safely.

• Sharps (needles, syringes, pen devices with needles): drop them into an FDA-cleared sharps disposal container. You can often get one at a pharmacy or online. If you don’t have one, a heavy-duty plastic container with a tight, puncture-resistant lid (like a laundry detergent jug) is a common backup where your area allows it — but check your local rules, because disposal laws vary by state and city.
• Never put loose sharps in the regular trash or recycling.
• Leftover medicine (like unused pills or an unopened pen you won’t use): a drug take-back location or event is the safest way to get rid of it. Many pharmacies and police stations host them.
• When a sharps container is about three-quarters full, seal it and dispose of it according to your local guidelines.

What to do right now: a 5-step check

Answer in one line: Read your carton, identify which of the four handling paths you have, find the controlling date, check the temperature and dose-count limits, and act on the earliest one. When the device, date, pharmacy instructions, or storage history are unknown, don’t guess — call the pharmacy.

1. 1

   Read the box and label.

   Don’t go on memory or the provider’s name — the label is the source of truth.

2. 2

   Which path is it?

   Single-dose injection, multi-dose injection, tablet, or compounded (use the four-path table above).

3. 3

   Find your controlling date.

   Printed expiration, first use, first puncture, day it left the fridge, or the pharmacy’s Beyond-Use Date.

4. 4

   Check temperature and doses.

   Inside the product’s range? Never frozen? Within the 30 / 30 / 4 rule if it’s a multi-dose tirzepatide device?

5. 5

   Act on the earliest limit.

   Use it, mark the discard date on the pen, or discard and refill. If anything’s unknown, call the pharmacy.

Skip the manual counting and let the tool apply all of this for you.

What we actually verified for this guide

Answer in one line: Each branded row was checked against the current U.S. prescribing information and Instructions for Use shown in the source column. Compounded-product dates are kept pharmacy-specific and are not generalized into a single number.

Because this is your health and your money, here’s exactly what we did and didn’t do.

Sources, in order of weight: (1) current FDA-approved labels and Instructions for Use, (2) FDA safety and compounding guidance, (3) CDC injection-safety guidance, (4) manufacturer support pages where the label needs plain-language clarification, and (5) patient forums — used only to understand the confusion, never as medical evidence.

Frequently asked questions

Still figuring out your next move?

If you just learned your current pen or vial is past its window — or it froze, overheated, or arrived warm — you may need to replace a dose sooner than you planned. That’s a normal thing to run into, and it doesn’t mean you did anything wrong.

If you already know you want FDA-approved, brand-name medication, Ro is one option worth a look — it lists FDA-approved GLP-1s including Zepbound® (tirzepatide) and Foundayo™ (orforglipron), and offers insurance support plus a free coverage checker. Ro Body membership runs $39 for the first month, then $149/month, or as low as $74/month when you prepay for a year — the medication itself is billed separately. (Prices and what’s in stock change, so check current pricing and availability on Ro’s site before you commit.)

But if you’re not sure what fits your budget, your insurance, or whether you want a pen, a vial, or a pill, don’t guess on that either. That’s exactly what our free tool is for.