How to store peptides depends on which peptide, in which form, and whether the vial has been opened, and the only reliable source for any of it is the label on the product in your hand. FDA-approved peptide drugs carry detailed storage sections, and they differ from one another in ways that matter when a package sits on a porch.
This page walks through what those labels say, what changes for a compounded vial, how a shipment is supposed to arrive, and what FDA advises when a medicine may have been kept outside its range. For what a month of each prescribable peptide costs, see the price boards.
What the approved labels say
The clearest examples are the GLP-1 peptides. Tirzepatide, sold as Zepbound, is labeled for the refrigerator at 2°C to 8°C (36°F to 46°F), with a single-dose pen or vial allowed up to 21 days in total unrefrigerated at no more than 30°C (86°F) [1]. The label says to discard it after those 21 days at room temperature [1].
Semaglutide, sold as Wegovy, has a similar structure with different numbers. A single-dose pen or syringe is labeled for the refrigerator, and before its cap comes off it can be kept at 8°C to 30°C (46°F to 86°F) for up to 28 days [2]. The patient instructions say to throw it away if it has been exposed to temperatures above 86°F [2].
Not every peptide needs cold. Vyleesi, the approved form of bremelanotide, is labeled “Store at or below 25°C (77°F). Do not freeze. Protect from light” [3].
| Product | Labeled storage | Time allowed out of the fridge |
|---|---|---|
| Zepbound single-dose pen or vial | Refrigerator, 2°C to 8°C | Up to 21 days total, not above 30°C |
| Zepbound multi-dose vial, opened | Refrigerator or up to 30°C | 30 days, or 4 weekly doses |
| Wegovy single-dose pen or syringe | Refrigerator, 2°C to 8°C | Up to 28 days at 8°C to 30°C, cap on |
| Vyleesi autoinjector | At or below 25°C | Not refrigerated; do not freeze |
Two rules repeat across the refrigerated labels. Both Zepbound and Wegovy say not to freeze the product and not to use it if it has been frozen, and both say to protect it from light by keeping it in its carton [1] [2].
Compounded vials follow the pharmacy's label
A compounded peptide such as sermorelin has no FDA-approved label, so there is no national storage section to look up. The storage instructions come from the pharmacy that made it, printed on the vial label or an insert, and they are the ones to follow.
A compounded peptide may arrive as a powder that is mixed with bacteriostatic water before use. The water itself is labeled for room temperature, 20°C to 25°C [4]. Its label also says not to store a mixed drug unless the drug's maker directs it [4], which again points back to the pharmacy's instructions for the mixed vial. More on the diluent is in the guide to bacteriostatic water.
How shipping is supposed to work
A refrigerated product has to reach you inside its labeled range, whatever packaging the pharmacy uses to get it there. The labels set the limits the trip has to respect: a refrigerated peptide should not freeze on the way, and it should not spend longer out of range than its label allows [1] [2].
That makes delivery timing part of storage. A box left outside in summer, or held over a weekend at a carrier depot, can use up a label's allowance before it is opened. Asking the seller which days it ships, and whether it avoids shipping late in the week, is a fair question for anyone in a hot or cold climate.
If the box arrives warm
FDA's guidance for medicines kept outside their recommended temperature is written for power outages and disasters, but the rule is general. It says to check the medicine's storage instructions, or contact a pharmacist, health care provider or the manufacturer, to find out whether it can still be used [5]. It also warns that temperature-sensitive medicines may lose potency when not stored at the recommended temperature [5].
In practice that means comparing what happened with what the label allows, and letting the pharmacy that shipped it make the call. Noting the delivery time and keeping the packaging gives the pharmacy something concrete to judge. Ask whether the product is still within its label, and whether the seller will replace a shipment that was not.
Replacement terms belong in the same conversation as price and cancellation. How prepaid plans handle refunds is covered in canceling a peptide subscription, and the supplies that come with a shipment are covered in the guide to peptide needles and syringes.
The one question to ask a seller before the first order is this: if a box arrives outside its temperature range, will you replace it, and how do I report it?