Out of the fridge: storage and beyond-use dating on a compounded GLP-1
The approved products put a number on it. A Wegovy pen may sit between 8 and 30 degrees Celsius for up to 28 days before its cap comes off. A Zepbound single-dose pen or vial gets 21 days at up to 30 degrees. An opened Zepbound multi-dose vial is thrown away after 30 days at room temperature, 30 days after first use, or after four weekly doses, whichever comes first. On compounded products, a 2026 survey found the number missing far more often than it was there.
What this comes down to
- Of 33 unique compounded semaglutide and tirzepatide products identified in early 2025, 18% reported a beyond-use date and preferred storage conditions, and 28% reported preferred storage conditions.
- The FDA recommends discarding a multi-dose sterile vial 28 days after first use, and says so even when the compounder's own instructions say longer.
- The agency says it has received complaints that compounded GLP-1 drugs arrived warm or with inadequate ice packs, and recommends not using one that does.
- Exposed to light, compounded semaglutide and the originator products diverged significantly in strength, total impurity and high-molecular-weight protein in a 2026 laboratory analysis.
What the approved labels allow, precisely
These figures come off the prescribing information for each product, read on the dates recorded below. They aren't interchangeable and they aren't roughly the same: a single-dose device and a multi-dose vial are governed by different rules, and the multi-dose rules turn on first use rather than on the date of purchase.
| Product and presentation | Refrigerated | Out of the refrigerator |
|---|---|---|
| Wegovy single-dose pen or syringe | 2 to 8 degrees Celsius | Up to 28 days at 8 to 30 degrees, before the cap is removed |
| Wegovy FlexTouch single-patient-use pen | 2 to 8 degrees Celsius before first use | After first use, 56 days at 15 to 30 degrees |
| Zepbound single-dose pen or single-dose vial | 2 to 8 degrees Celsius | Up to a total of 21 days not exceeding 30 degrees |
| Zepbound multi-dose vial or KwikPen, unopened | Until the expiration date on the label | 30 days at up to 30 degrees |
| Zepbound multi-dose vial or KwikPen, opened | 2 to 8 degrees Celsius | 30 days at room temperature, 30 days after first use, or 4 weekly doses |
Room-temperature allowances printed on the approved labels, as read September 11, 2026
Both labels also say not to freeze the product and not to use it if it has been frozen, and both say to protect it from light and keep it in its original carton[1][2]. The carton instruction is easy to treat as packaging advice. It isn't: light exposure is one of the two conditions under which a 2026 analysis found compounded semaglutide and the originator products diverging in strength and impurity content[5], which is covered in the impurities article.
What compounded products publish
One group went looking. Between February 3 and March 20, 2025 they searched compounding sites and identified 33 unique semaglutide or tirzepatide products whose strength, route or formulation differed from the approved ones. Of those 33, 18% reported information about a beyond-use date and preferred storage conditions, and 28% reported preferred storage conditions[3].
An expiration date comes off stability testing the manufacturer performed on that formulation in that container. A beyond-use date is assigned by the compounding pharmacy, under pharmacy standards, and it is the date after which the preparation should not be used. The two are set by different people using different evidence, and a compounded preparation has the second kind, when it has one at all.
PubMed, via the E-utilities API
("compounded semaglutide"[tiab] OR "compounded tirzepatide"[tiab]) AND (stability[tiab] OR "beyond-use"[tiab] OR "beyond use"[tiab] OR storage[tiab] OR degradation[tiab])Returned 2. Positive control — insulin, identical filter — returned 17676 through the identical filter in the same session.
Insulin is the control because it is the other refrigerated self-injected peptide most households keep, and its handling literature runs to five figures. The two hits here are the impurity analysis and the formulations survey already cited on this page — neither is a dedicated stability study of a compounded GLP-1 preparation.
The FDA's two storage instructions
The agency addresses compounded GLP-1 storage directly on the page we read, dated September 1, 2026[4]. Its first instruction is about vials that hold more than one dose, which is how most compounded GLP-1s on these platforms are shipped.
“Do not continue using medication from the vial after 28 days, even if instructions from the compounder say the medication can be used for longer than 28 days.”
[4]
The second is about how the product got to you. The agency says injectable GLP-1 drugs require refrigeration as indicated in their package inserts, that it has received complaints of compounded GLP-1 drugs arriving warm or with inadequate ice packs, and that it recommends patients not use a drug that arrives that way. Nothing about a delivery box tells you what the temperature was in the middle of it, which is the honest limit of that advice.
A discarded vial is a month of medication you paid for. Sellers that ship a large multi-dose vial priced by the milligram are pricing a supply that has a clock on it once it's opened, and that clock is not always the same as the plan's billing month. The calculator keeps a medication charge apart from a membership charge for the same reason: the two run on different schedules.
How the sellers we have read describe it
A vial is the default presentation here. Fourteen priced lines across four of our 242 sellers name a vial in the product label the seller wrote, from single-dose vials up to large multi-milligram ones. Blis MD publishes a lowest-dose and a highest-published-dose vial as separate lines, and Pepti prices its vial as an all-in monthly charge.
What none of them can tell you from a price list is the beyond-use date the pharmacy assigned. That's a question for the seller, not for a comparison table. How we source what we do print is in how we verify prices.
The other thing a large vial changes is how a dose gets measured, since the strength printed on it decides what a mark on a syringe is worth. That is its own problem, and it has a case series behind it.
Questions people actually ask
How long can a compounded semaglutide vial stay out of the fridge?
Whatever the compounding pharmacy's beyond-use date and storage instructions say, which a 2026 survey found only a minority of products published. The approved products give exact figures for their own presentations, and the FDA separately recommends discarding any multi-dose sterile vial 28 days after first use, even where a compounder's instructions say longer.
My GLP-1 arrived warm. Is it still good?
The FDA's recommendation, on its page dated September 1, 2026, is not to use an injectable GLP-1 drug that arrives warm or with insufficient refrigeration, because that can affect the drug's quality. It also asks people to report the problem to the compounder or the platform, and to MedWatch. We are not a clinical service and cannot assess an individual shipment.
What is a beyond-use date?
The date a compounding pharmacy assigns, after which its preparation should not be used. It's set under pharmacy standards rather than from the manufacturer stability testing that produces an expiration date on an approved product, and the two are not the same kind of claim even though they look alike on a label.
Does light really matter for these drugs?
The approved labels say to protect the product from light and keep it in the original carton until it is used. A 2026 laboratory analysis found significant disparity in strength, total impurity and high-molecular-weight protein between compounded semaglutide and originator products after light exposure, which is a measurement in a lab rather than an outcome in people.
Sources
Every source here was fetched and read for this article, with the identifier taken off the record that came back and the claim it supports written down beside it. All of it was read in September 2026, the same session the rest of this page draws on.
- 1.WEGOVY (semaglutide) injection, solution; WEGOVY (semaglutide) tablet — prescribing information. Novo Nordisk, via the DailyMed Structured Product Labeling service, 2026. Source · Document dated June 2026Refrigerated storage at 2 to 8 degrees Celsius; up to 28 days at 8 to 30 degrees for a single-dose pen or syringe prior to cap removal; 56 days at 15 to 30 degrees for the single-patient-use FlexTouch pen after first use; the instructions not to freeze, to protect from light, and to keep the product in its original carton until administration.
- 2.ZEPBOUND (tirzepatide) injection — prescribing information. Eli Lilly and Company, via the openFDA label API, 2026. Source · Document dated August 2026Refrigerated storage at 2 to 8 degrees Celsius; up to a total of 21 days not exceeding 30 degrees for a single-dose pen or vial; 30 days at room temperature for an unopened multi-dose vial or KwikPen; and the rule to discard an opened multi-dose vial or KwikPen after 30 days at room temperature, 30 days after first use, or after four weekly doses.
- 3.Compounded Semaglutide and Tirzepatide Products Use Unique Formulations but Efficacy and Safety Largely Unknown. Annals of Pharmacotherapy, 2026. PMID 41689811 · doi:10.1177/10600280261421979Thirty-three unique compounded semaglutide or tirzepatide products identified between February 3 and March 20, 2025, of which 18% reported information about beyond-use date and preferred storage conditions and 28% reported preferred storage conditions.
- 4.FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. U.S. Food and Drug Administration, 2026. Source · Document dated September 2026The recommendation that multi-dose sterile vials be discarded within 28 days after first use including the verbatim instruction not to continue past 28 days even where a compounder says otherwise; and the statement that injectable GLP-1 drugs require refrigeration, that complaints have been received of products arriving warm or with inadequate ice packs, and that patients should not use such a product.
- 5.Impurities and Potential Immunogenicity Associated With Follow-on and Compounded Glucagon-like Peptide-1 Receptor Agonists. Pharmaceutical Research, 2026. PMID 42533250 · doi:10.1007/s11095-026-04146-9Significant disparity in strength, impurity sum and high-molecular-weight protein level between compounded semaglutide and originator products when exposed to light, from a photostability arm of the same analysis.
Key figures