Labels onlyStorage limits come from stability testing that a manufacturer submits for an approved product. Peptides sold as "research use only" have no approved label, so no tested storage or in-use limit exists for them. This page reports what the labels say and nothing more.
Peptide storage on FDA labels
Each approved peptide product has its own storage rules, before and after mixing; the table collects them.
| Product | Before mixing | After mixing | Freezing and light |
|---|---|---|---|
| Egrifta, original 1 mg vial (2010)[1] | Refrigerated at 2–8 °C | Inject immediately | — |
| Egrifta SV (tesamorelin 2 mg)[2] | 20–25 °C | Use immediately; discard leftover solution and water | Do not refrigerate or freeze after mixing; protect from light |
| Egrifta WR (tesamorelin 11.6 mg)[3] | 20–25 °C in the original carton | Keep at 20–25 °C; discard 7 days after mixing | Do not freeze |
| Vyleesi (bremelanotide autoinjector)[4] | At or below 25 °C | No mixing; single use | Do not freeze; protect from light |
| Bacteriostatic water (the diluent)[5] | 20–25 °C | No in-use period stated | — |
Three of the four drug products are room-temperature products. That surprises people who assume every peptide belongs in the fridge.
Do peptides need to be refrigerated?
Not always: storage depends on the formulation, not on the peptide's name. The clearest example is tesamorelin itself. The original Egrifta vials were refrigerated,[1] while today's Egrifta SV and Egrifta WR are stored at room temperature, 20–25 °C.[2][3] Same molecule, different products, different rules.
For any product without an approved label, the honest answer is that nobody has published tested data. Advice found on seller sites is not a stability study.
How long do peptides last after reconstitution?
On the labels, from "immediately" to 7 days; for everything else, unknown.
- Egrifta (2010) and Egrifta SV: use immediately after mixing, and throw away what is left.[1][2]
- Egrifta WR: one vial gives 7 daily doses, and the label says "Discard unused solution of EGRIFTA WR vial 7 days after mixing".[3]
- Vyleesi: nothing to mix; each autoinjector is used once.[4]
- Everything else: no labeled limit. Bacteriostatic water's own label says not to store reconstituted solutions "unless otherwise directed by the manufacturer of the solute".[5] For an unapproved peptide, there is no manufacturer direction to follow.
The often-quoted "28 days" comes from a different rule: the CDC, citing USP 797, says an opened multiple-dose vial should be dated and discarded within 28 days unless its manufacturer states otherwise.[6] That is a limit for the opened container in healthcare settings, not a stability result for any peptide. Note also that the preservative in bac water does not turn into an in-use date for the drug dissolved in it. Egrifta WR uses bac water and still sets its own 7-day limit.[3]
Why research peptides have no storage answer
Storage limits are part of what the FDA reviews before approval, so an unapproved product has none that anyone has checked. The FDA's safety notes for TB-500, ipamorelin and injectable GHK-Cu mention "aggregation", peptide molecules clumping together, and several notes mention "peptide-related impurities".[7] Without stability data, there is no way to know how temperature or time after mixing affects either. The safety page covers what the FDA has said about these products.
What the labels have in common
Read side by side, the approved labels repeat a few rules:
- Do not freeze (Egrifta SV after mixing, Egrifta WR, Vyleesi).
- Protect from light (Egrifta SV, Vyleesi).
- Keep in the original carton (Egrifta WR).
- Time limits run from mixing (Egrifta WR's 7 days).
- Different products of the same molecule are not interchangeable: the Egrifta WR label says it and Egrifta SV "are not substitutable".[3]
Related pages
- Bac water for peptidesWhat the diluent label says
- How to reconstitute peptidesMixing math and label instructions
- Tesamorelin calculatorEgrifta SV and WR doses in mL and units
Frequently asked questions
Do peptides need to be refrigerated?
How long do peptides last after reconstitution?
Sources
- Egrifta (tesamorelin) prescribing information, original 2010 label
- Egrifta SV (tesamorelin) prescribing information
- Egrifta WR (tesamorelin) prescribing information
- Vyleesi (bremelanotide) prescribing information
- Bacteriostatic Water for Injection, USP (Hospira) label
- Preventing unsafe injection practices (multi-dose vials, citing USP 797)
- Certain bulk drug substances for use in compounding that may present significant safety risks