Store a peptide exactly as its label says, because the labels do not agree with each other. Of the four FDA-approved labels here, two call for the refrigerator, one allows a set number of days at room temperature, and two are stored at room temperature from the start. Once a powder is mixed, the rules change again.
This page reads four approved labels side by side. It is not a storage guide for any research-only compound such as BPC-157, which has no label.
Ready-to-use solutions
The tirzepatide label for ZEPBOUND is the most detailed [1]. Single-dose pens and vials are refrigerated at 2°C to 8°C. If needed, each can be kept unrefrigerated at up to 30°C for a total of 21 days, then discarded. Opened multi-dose vials and pens are thrown away after 30 days at room temperature, 30 days after first use, or 4 weekly doses, whichever comes first, even if medicine remains.
The bremelanotide label for VYLEESI is simpler: store at or below 25°C, do not freeze, and protect from light [2].
Powders that must be mixed
The tesamorelin label for EGRIFTA SV keeps the powder vials at room temperature, 20°C to 25°C, protected from light in the original box [3]. After mixing, the dose is injected immediately. The label says not to store, freeze or refrigerate the mixed solution.
The somatropin label for GENOTROPIN takes the opposite approach [4]. The powder is refrigerated at 2°C to 8°C until its expiration date, and must not be frozen. Once mixed, the cartridge stays refrigerated between uses for up to 28 days, and must not be shaken.
Why peptides are fussy about storage
Protein and peptide drugs are prone to both chemical and physical instability, and a standard review of the field treats stabilization in the dried state as one of the main routes to a stable product [5]. That helps explain why some peptides ship as powders, and why a mixed solution comes with its own, shorter clock.
What about research-only peptides?
When the FDA reviewed BPC-157 and MOTS-c for compounding in July 2026, its briefing documents reported literature describing the raw substances as expected to be stable when stored below −18°C and −20°C respectively [6]. Those are properties of a raw ingredient, not instructions for any finished product, and the FDA concluded against listing either substance. The regulatory picture is in what the research shows on MOTS-c.
Mixing is covered in how to reconstitute peptides, and the choice of liquid in bacteriostatic water for peptides. If a product has been left out longer than its label allows, the dispensing pharmacist is the person to ask.