How long does semaglutide last? Learn fridge and room-temperature storage limits, compounded 28-day rules, and how to spot expired semaglutide safely.
Semaglutide lasts about one week per dose in the body, which is why it is injected weekly, and it takes roughly five weeks to clear your system after the last injection. How long it lasts in storage is a separate question: brand-name pens remain usable for 28 to 56 days after first use depending on the product, and compounded vials last until the beyond-use date printed on the label. In short, there are two timelines to track — one for your body and one for your refrigerator.
How Long Semaglutide Stays in Your Body
Semaglutide has a half-life of about seven days, so roughly half of a dose is still circulating a week after you inject it. That long half-life is exactly why the medication is dosed once weekly instead of daily.
Blood levels reach steady state after about four to five weeks of consistent weekly dosing. After your final dose, it takes about five half-lives — close to five weeks — for most of the drug to leave your system.
| Milestone | Approximate timing |
|---|---|
| Half-life of semaglutide | About 7 days |
| Time to steady state | 4 to 5 weeks of weekly dosing |
| Time to clear after the last dose | About 5 weeks |
These figures are averages, and individual metabolism, dose, and injection technique can shift them a little.
How Long Brand-Name Semaglutide Lasts in Storage
Ozempic, Wegovy, and Rybelsus each have their own storage rules, and the countdown usually begins when you first use or open the product.
| Product | Before first use | After first use | Maximum time at room temperature |
|---|---|---|---|
| Ozempic pen | Refrigerate at 36–46°F | Refrigerate or keep at room temp | Up to 56 days |
| Wegovy pen | Refrigerate at 36–46°F | Refrigerate or keep at room temp | Up to 28 days |
| Rybelsus tablets | Room temperature in the original blister pack | Room temperature in the blister pack | Follow the bottle instructions |
Two rules apply to every form: never freeze semaglutide, and keep it away from direct sunlight and heat. A pen that has been frozen should be discarded even if it looks completely normal.
How Long Can Semaglutide Be Unrefrigerated?
After the first use, an Ozempic pen can stay at room temperature, up to 86°F, for a total of 56 days whether or not you refrigerate it between doses. A Wegovy pen can stay at room temperature for up to 28 days after first use. Before the first use, both products belong in the refrigerator.
Room temperature is not the same as a hot car. A pen left in a glovebox on a summer afternoon can blow past 86°F in minutes, and heat degrades the peptide. If your medication gets too warm, freezes, or sits in direct sun, replace it rather than guess.
Anyone who mixes their own peptides should also check how long is bac water good for in the fridge, because the diluent has its own shelf life once the seal is broken.
Does Compounded Semaglutide Expire After 28 Days?
Compounded semaglutide does not have an FDA-approved expiration date. Instead, the compounding pharmacy assigns a beyond-use date, or BUD, based on its formulation, testing, and USP compounding standards.
The 28-day figure comes from general multi-dose vial guidance, not from a rule written specifically for semaglutide. Many 503A and 503B pharmacies assign BUDs between 28 and 90 days, and refrigerated, preserved formulations sometimes carry longer dates.
The label on your vial is the final word. If it says to discard 28 days after the first puncture, that date stands even if the vial still looks full, so write the puncture date on the label with a marker.
How long is a semaglutide vial good for in the fridge?
A refrigerated compounded vial is generally good until the BUD on its label when it is stored between 36°F and 46°F. Keep it upright in its original carton, away from the freezer compartment and away from door shelves where the temperature swings.
What Happens If You Use Expired Semaglutide?
Using expired semaglutide is usually not an emergency, but it is a risk with no upside. The most common outcome is reduced potency, which can show up as weaker appetite control or higher blood sugar than you normally see.
Multi-dose vials that are past their beyond-use date also carry a higher chance of bacterial contamination, especially after many punctures. Contaminated product can cause redness or swelling at the injection site, and in rare cases fever or a more serious infection.
Discard the medication if you notice any of the following:
- Cloudy, discolored, or grainy liquid
- Floating particles or visible specks
- A cracked pen, damaged seal, or leaking stopper
- A vial that is past its beyond-use date
- Any sign the product was frozen or overheated
When in doubt, do not inject it. Call your pharmacy, explain what happened, and ask about a replacement.
Safety, Side Effects, and When to Ask a Professional
Storage problems and side effects are separate concerns, and one does not explain the other. Many people search does everyone have side effects from semaglutide before their first dose, and the answer is no — plenty of users have mild symptoms or none at all.
Timing questions are common across the peptide world as well. People comparing options often ask how long does retatrutide take to work or how long does sermorelin take to work, and the honest answer depends on dose, delivery route, and how the product was stored.
Semaglutide is a prescription medication in the United States, and it is not approved for casual weight-loss or wellness use outside its labeled indications. Talk to your prescriber or pharmacist before restarting an old pen, stretching a vial past its beyond-use date, or switching products.
Frequently Asked Questions
How long can semaglutide be unrefrigerated?
After the first use, an Ozempic pen can stay at room temperature, up to 86°F, for a total of 56 days, while a Wegovy pen can stay out for up to 28 days. Before first use, both products should stay refrigerated between 36°F and 46°F. Never freeze semaglutide or leave it in a hot car.
Does compounded semaglutide expire after 28 days?
Not automatically. The 28-day rule comes from general multi-dose vial guidance, and the binding number is the beyond-use date your pharmacy printed on the vial. Some pharmacies assign 28 days, while others assign 60 to 90 days for refrigerated formulations. Always follow the label on your own vial.
What happens if you use expired semaglutide?
The most likely result is reduced potency, so appetite suppression or blood sugar control may be weaker than expected. Expired multi-dose vials also carry a higher risk of bacterial contamination. Discard the vial if the liquid is cloudy, discolored, or contains particles, and ask your prescriber or pharmacist for a replacement.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.