How Long Does Compounded Tirzepatide or Semaglutide Last in the Fridge? (And Does It Expire?)

A compounded tirzepatide or semaglutide vial lasts until the beyond-use date printed on its label — and that date is set by the pharmacy that made it, not by the drug. There is no single number that applies to every compounded vial. Keep it in the refrigerator (36°F to 46°F), never freeze it, and throw it out on the label date even if there is medicine left.

The day counts you see online — 21 days, 28 days, 56 days — come from the branded products' labels. They are useful for comparison, but they describe Zepbound's and Wegovy's own formulations, not yours.

How long does compounded tirzepatide last in the fridge?

As long as the beyond-use date on your vial says. A compounding pharmacy assigns that date for the specific preparation it made, based on how it was compounded, what is in the vial (preservative, additives such as B12) and how it was tested. Two pharmacies can give the same drug very different dates.

For comparison, Lilly's label says an unopened Zepbound multi-dose vial kept in the refrigerator can be used "until the expiration date on the label," and once opened must be thrown away "after a total of 30 days at room temperature, 30 days after first use, or after taking 4 weekly doses"¹.

How long does compounded semaglutide last once opened?

Again, until the beyond-use date on its label. Many compounded vials hold several weeks of doses, so ask the seller before you order whether the date covers the whole vial at your dose.

On the branded side, a Wegovy FlexTouch pen can be kept for 56 days after first use, at room temperature or in the refrigerator².

Does it go bad at room temperature or if it freezes?

Freezing: both branded labels say not to use the drug if it has frozen¹². Keep vials away from the back wall and cooling element of the refrigerator.

Room temperature: the branded labels allow limited time out of the refrigerator — up to 21 days for a Zepbound single-dose pen or vial at or below 86°F¹, and up to 28 days for a Wegovy single-dose pen or syringe before the cap is removed². Those allowances were tested for those products. A compounded vial gets only what its own label or pharmacy says. If yours sat out — a late delivery, a warm car — call the pharmacy before using it.

Sellers do not always agree with themselves on this. BetterMe Rx's returns policy says it does not ship refrigerated products, while its product pages say to keep the same medication at 36°F to 46°F. Nex Gen Health Rx describes refrigeration both ways on different pages. Ask how your order ships before you need to know.

Where do I find my vial's beyond-use date?

On the pharmacy label on the vial or its box, usually marked "BUD," "Use by" or "Discard after." If you cannot find one, ask the dispensing pharmacy — it is the only source for that number. Write the date you first pierced the vial on the box.

If your vial is a powder you mix yourself, the diluent changes the date too. Our reconstitution and storage article shows how the same drug gets different dates depending on the water used, and our bacteriostatic water guide explains why.

What do the Zepbound and Wegovy labels say for comparison?

The table above has the full list. The short version: refrigerate, never freeze, protect from light, and count the days out of the refrigerator. Lilly also says to keep Zepbound in its original carton¹; Novo says the same for Wegovy².

What are signs a vial shouldn't be used?

• •It is past the beyond-use date on its label.
• •It has been frozen.
• •It looks different than it should. Lilly's label says Zepbound "should appear clear and colorless to slightly yellow" and not to use it "if particulate matter or discoloration is seen"¹. Ask your pharmacy what yours should look like.
• •It spent time at room temperature longer than your pharmacy allows.
• •The vial or seal is damaged.

When in doubt, call the pharmacy that dispensed it. For dose amounts, see our tirzepatide and semaglutide dosing charts; for technique, where to inject tirzepatide and semaglutide.