Storing peptides

Why are peptide drugs stored cold?

Protein and peptide drugs are open to physical and chemical instabilities such as aggregation, adsorption to surfaces, deamidation, chain cleavage, and oxidation, and to breakdown by enzymes. ^[12] For this reason, the shelf life and storage conditions of each licensed product are defined in its own SmPC, specific to that product, and one product’s rule is not transferred to another: even two products carrying the same active substance (for example the Mounjaro pen and vial) have different periods. ^{[4] [5]}

The SmPCs also describe signs that storage has been compromised. According to the Ozempic and Saxenda SmPCs, the product is not used if the solution does not appear clear and colorless or almost colorless, or if it is frozen. ^{[1] [6]} According to the Mounjaro SmPC, the product is visually inspected before use; if there are particles or a color change, it is not used and is discarded, and a frozen product is not used. ^[4]

How are GLP-1 pens in Türkiye stored according to the label?

The table below is summarized from sections 6.3 and 6.4 of the SmPCs approved by TİTCK (Turkish Medicines and Medical Devices Agency). Product information may be updated over time; what applies is the current SmPC and patient information leaflet in the package.

The Mounjaro KwikPen contains four weekly doses; according to the SmPC, the pen is discarded after the four weekly doses. ^[4] Usage details are on the How is Ozempic used? and How is Mounjaro used? pages.

Is the needle left on the pen?

No. According to the Ozempic SmPC, the patient should be advised to discard the needle after each injection and to store the pen without the needle attached; this prevents needle blockage, contamination, infection, leakage of solution, and inaccurate dosing. The same SmPC states that the pen is for use by one person only. ^[1] The Wegovy and Saxenda SmPCs state storage without the needle attached for the same reason. ^{[3] [6]}

What to watch for while traveling and at home

In the “Care of your pen” section, the Ozempic patient information leaflet states that the pen should not be left in a car or elsewhere where it may become very hot or very cold, and that Ozempic that has been exposed to direct sunlight or frozen should not be injected; it notes that the desired effect of the medicine may not be obtained in these cases. The same leaflet states that the pen should not be exposed to dust, dirt, or liquid, should not be washed, and should not be dropped. ^[2] According to the leaflet, the medicine is kept in its package, out of the sight and reach of children. ^[2]

How are used pens and needles disposed of?

The SmPCs state that unused products and waste materials are destroyed in accordance with the “Medical Waste Control Regulation” and the “Packaging Waste Control Regulation.” ^{[1] [4]} The Saxenda SmPC additionally states that the used needle must be discarded after each injection in accordance with the requirements of the Medical Waste Control Regulation. ^[6] According to the Ozempic patient information leaflet, expired or unused medicines are not thrown in the trash but handed over to the collection system designated by the Ministry of Environment, Urbanization and Climate Change. ^[2]

What are the cold chain and counterfeit product risks?

Storage rules rest on the assumption that the product arrives under the right conditions from the manufacturer to the pharmacy. Two separate problems have been documented for products obtained outside this chain: counterfeit products with different content, and products transported under the wrong conditions.

• WHO, June 2024: Three counterfeit Ozempic batches were detected in Brazil (October 2023), the UK (October 2023), and the US (December 2023), and these had been distributed in the regulated supply chain. According to the WHO, a counterfeit product may lead to ineffective treatment because of incorrect dose, contamination with harmful substances, or containing unknown or other substances, and because it is injected subcutaneously it may carry life-threatening risks. The alert lists as distinguishing signs of counterfeit pens a scale that extends outside the pen when the dose is being set, a low-quality label that does not adhere well to the pen, and spelling errors on the box. ^[7]
• UK medicines authority (MHRA), November 2023: By October 2023, 369 suspected counterfeit Ozempic pens had been seized; pens containing insulin relabeled as Ozempic were caught. By 20 November 2023, 16 reports had been received about suspected counterfeit products claimed to contain semaglutide or liraglutide; in five cases, Saxenda and Ozempic pens were confirmed to be counterfeit products containing insulin; some people were hospitalized and serious side effects, including hypoglycemic shock, were reported. The MHRA states that Ozempic and Saxenda in the legal supply chain are not affected. ^[8]
• US Food and Drug Administration (FDA): Injectable GLP-1 drugs require refrigeration as stated in their package inserts. The FDA reports that it has received complaints that some compounded GLP-1 products arrived hot or with inadequate ice packs and advises that no injectable GLP-1 product that arrives hot or inadequately cooled be used. ^[9] The FDA also states that in multi-dose sterile drug vials, the risk of contamination increases over time after first use. ^[9]
• European Medicines Agency (EMA) and EU Heads of Medicines Agencies (HMA), September 2025: They announced a sharp rise in illegal medicines marketed as GLP-1 receptor agonists, saying these products are mostly sold through fake websites and social media, may not contain the declared active substance at all, and may contain other substances at harmful levels. ^[10]

The licence and reimbursement status of these drugs in Türkiye is described in the relevant drug guides: Semaglutide, Tirzepatide, Liraglutide.

How are unlicensed “research” peptides stored?

There is no safe answer to this question. For an unlicensed vial, neither shelf life, nor storage condition, nor sterility has been evaluated by an authority; the storage information written on the label is unverified, like the product itself. No storage method makes a product of unknown content and sterility safe. This guide gives no information on preparing, mixing, or storing unlicensed products.

Measured findings show that this uncertainty is concrete. In a market surveillance study by a Hungary-based research team, three freeze-dried semaglutide vials obtained from illegal online pharmacies selling without a prescription, with “for research use only” on their labels, were examined in the laboratory. No live microorganisms were found in the vials at the time of testing; however, endotoxin (a residue of the Gram-negative bacterial cell wall) was detected in all three samples, with levels between 2.1645 and 8.9511 EU/mg. Measured purity was between 7.7% and 14.37% and was markedly far from the 99% claim on the labels; the semaglutide amount exceeded what was written on the label by 28.56–38.69%. In the same study, three Ozempic pens that were ordered were never delivered. ^[11] The study examines only three vials and may not represent the whole market.

The FDA also reports that it has warned companies about products containing substances such as semaglutide, tirzepatide, and retatrutide that are falsely labeled “for research purposes” or “not for human consumption” and sold directly to consumers with dosing instructions, and that the quality of these products is unknown and they may be harmful to health. ^[9] The legal and practical meaning of the “for research use” label is covered in detail in the What is a research peptide? guide.

Where to go after this guide?

How long a drug stays in the body after it is stopped is covered in What does half-life mean?, and the GLP-1 hormone and drugs in the What is GLP-1? and GLP-1 agonists guides. The general definition of peptides is in What are peptides?, their types in Types of peptides, legal status in Are peptides legal?, and side effects in Peptide side effects. The decision on whether a product that has been outside storage conditions can be used is made by a pharmacist and physician according to the product’s current SmPC.