OptiPin
Beyond-use date calculator
When to throw away a vial you mixed or a pen you started. Each date shows where it comes from: the product label, the pharmacy rule or nothing at all.
The short answer
If the product has a label, the label's in-use window is the date: 60 days for Pregnyl, 30 for Novarel, 28 for most growth hormone cartridges and 56 days after first use for an Ozempic pen. If you mixed a peptide yourself with bacteriostatic water, nobody has tested your vial. The 28-day rule for opened multiple-dose vials is a ceiling for contamination, not a promise about the peptide.
Mixed with plain sterile water there is no preservative at all. The strictest published reference, USP <797>'s immediate-use rule, allows 4 hours from the start of mixing. Treat it as a single dose.
OptiPin dates every vial for you
Log a reconstitution once and OptiPin tracks the beyond-use date, what is left in the vial and when to reorder. On your phone, with no account and nothing in the cloud.
Download on the App StoreHow to use this calculator
Three kinds of date: only one is about your product
- The label's in-use window. The manufacturer tested that product in that container with that diluent, then wrote the result on the label. It is the only one of the three that describes the medicine itself.
- The multiple-dose vial rule. CDC guidance says an opened multiple-dose vial should be dated and discarded within 28 days unless the manufacturer gives another date. USP <797> says the same for pharmacies. The rule exists because every needle entry is a chance to contaminate the vial. A preservative only holds that off for so long. It says nothing about whether the drug inside is still intact.
- The immediate-use rule. For something mixed outside a clean room from no more than three sterile products, USP <797> requires administration to begin within 4 hours of the start of preparation, or the preparation is discarded. Plain sterile water has no preservative, which is why this is the reference point for it.
When two of them apply, the shorter wins. The peptide storage guide goes deeper into why the numbers quoted online disagree and what physically degrades a peptide in solution.
In-use windows from US labels
Every figure below is from the product's US prescribing information or patient instructions on DailyMed. The clock starts at the point in the second column.
| Product | Clock starts | Refrigerated | Room temperature |
|---|---|---|---|
| Pregnyl (hCG) | Mixing | 60 days | Not on label |
| Novarel (hCG) | Mixing with bacteriostatic water | 30 days | Not on label |
| Chorionic Gonadotropin, Fresenius Kabi | Mixing | 60 days | Not on label |
| Omnitrope 5 or 10 mg cartridge | First injection | 28 days | Not on label |
| Omnitrope 5.8 mg vial | Mixing | 21 days | Not on label |
| Genotropin 5 or 12 mg cartridge | Mixing | 28 days | Not on label |
| Genotropin MiniQuick | Mixing | 24 hours, single use | Not on label |
| Norditropin FlexPro | First injection | 4 weeks | 3 weeks at up to 25 °C |
| Humatrope cartridge | Mixing | 28 days | No more than 30 minutes a day |
| Egrifta WR (tesamorelin) | Mixing | Do not refrigerate | 7 days at 20–25 °C |
| Ozempic pen | First use | 56 days, refrigerated or at 15–30 °C | |
| Wegovy FlexTouch pen | First use | 56 days, refrigerated or at 15–30 °C | |
| Wegovy single-dose pen | Out of the refrigerator | Until the carton expiry date | 28 days at 8–30 °C |
| Mounjaro or Zepbound KwikPen or multi-dose vial | First use | 30 days or 4 weekly doses, whichever comes first | |
| Mounjaro or Zepbound single-dose pen or vial | Out of the refrigerator | Until the carton expiry date | 21 days in total, up to 30 °C |
| Victoza or Saxenda pen | First use | 30 days, refrigerated or at 15–30 °C | |
| Trulicity pen | Out of the refrigerator | Until the carton expiry date | 14 days in total, up to 30 °C |
Labels change. Labels outside the US can differ. The leaflet in your own box overrides this table. The hCG windows assume the diluent the label names: Pregnyl's own solvent and the bacteriostatic water named on the Novarel and Fresenius Kabi labels both contain 0.9% benzyl alcohol.
When there is no data: research peptides
A vial of BPC-157, TB-500, retatrutide or any other peptide bought for research comes with no in-use testing at all. Nobody has measured how long it stays intact once dissolved, at what concentration or in which water. Stability in solution varies widely from one peptide to the next, so a single number quoted across all of them is a guess.
So the calculator does not invent one. With bacteriostatic water and refrigeration it shows the 28-day multiple-dose rule and labels it as a contamination limit. At room temperature it shows no date, because no published source gives one and a mixed vial is not meant to be kept that way. If a vial will outlast 28 days at your dosing rate, the fix is a smaller vial or less powder per mix, not a longer date.
Pharmacy-compounded vials
A vial from a compounding pharmacy carries a beyond-use date the pharmacy assigned. Under USP <797>, once a multiple-dose compounded vial is first punctured it can be used for the shorter of that assigned date or 28 days. Enter the label date and the day you first drew from the vial. The calculator applies whichever comes first. The vial longevity calculator tells you whether the doses run out before either date.
Throw it away sooner if
- The liquid is cloudy, colored or has particles, unless the label says that is normal for the product.
- It has been frozen. Nearly every label in the table says not to freeze. Freeze–thaw also damages peptides in solution.
- It has been left somewhere hot, such as a car in summer.
- The rubber stopper has been cored or damaged, or you cannot remember when you mixed it.
- You see signs of infection where you injected from it.
Frequently asked questions
What is a beyond-use date?
It is the date after which a prepared or opened medicine should not be used. An expiry date applies to the sealed product as made. A beyond-use date starts when you change it by mixing, opening or puncturing it. It is usually much shorter. Pharmacies assign one to anything they compound under USP <797>.
How long does reconstituted hCG last?
It depends on the brand. Pregnyl's US label gives 60 days refrigerated after mixing and the Fresenius Kabi chorionic gonadotropin label also gives 60. Novarel's label gives 30 days when mixed with bacteriostatic water. Mixed with plain sterile water, none of those windows apply and it should be treated as single use.
How long does a peptide mixed with bacteriostatic water last?
For a research peptide there is no tested answer. The working ceiling is the 28-day rule for opened multiple-dose vials from CDC and USP <797>, which is about contamination rather than the peptide. Keep it refrigerated and treat 28 days as the latest date, not a guarantee that it is still at full strength.
What if I mixed it with sterile water instead?
Plain sterile water has no preservative, so the vial has nothing to slow bacterial growth once a needle has been in it. The strictest published reference is USP <797>'s immediate-use rule: administration begins within 4 hours of the start of mixing. Anything left over is discarded.
When does an Ozempic pen expire after first use?
56 days after the first injection, whether you keep it in the refrigerator or at 15–30 °C, per the US label. Throw it away at 56 days even if medicine is left in it. Wegovy FlexTouch pens follow the same 56-day rule.
How long can Mounjaro or Zepbound stay out of the fridge?
A single-dose pen or vial can be kept unrefrigerated, up to 30 °C, for a total of 21 days. A KwikPen or multi-dose vial is discarded 30 days after first use, or after 4 weekly doses, whichever comes first, even if medicine is left in it.
Sources
- Centers for Disease Control and Prevention. Preventing unsafe injection practices: an opened multiple-dose vial should be dated and discarded within 28 days unless the manufacturer states another date.
- Washington State Pharmacy Quality Assurance Commission. USP <797> Sterile Compounding Self-Inspection Addendum (DOH 690-296): quotes USP <797> on immediate-use preparations (administration within 4 h), multiple-dose containers (28 days unless labeled otherwise) and punctured multiple-dose compounded preparations (the shorter of the assigned date or 28 days).
- American Society of Health-System Pharmacists. USP <797> key changes (2023): the immediate-use limit moved from 1 hour to 4 hours in the 2023 revision.
- PREGNYL (chorionic gonadotropin) – US label, DailyMed: discard the refrigerated reconstituted solution after 60 days; the solvent contains 0.9% benzyl alcohol.
- NOVAREL (chorionic gonadotropin) – US label, DailyMed: reconstituted with bacteriostatic water, refrigerate and use within 30 days.
- Chorionic Gonadotropin (Fresenius Kabi) – US label, DailyMed: the refrigerated reconstituted vial is discarded after 60 days.
- OMNITROPE (somatropin) – US label, DailyMed: cartridges 28 days refrigerated after first use; the 5.8 mg vial 21 days after mixing.
- GENOTROPIN (somatropin) – US label, DailyMed: cartridges 28 days refrigerated after mixing; MiniQuick single use, up to 24 hours refrigerated.
- NORDITROPIN (somatropin) – US label, DailyMed: after the first injection, 4 weeks refrigerated or 3 weeks at up to 25 °C.
- HUMATROPE (somatropin) – US label, DailyMed: reconstituted cartridges 28 days refrigerated, no more than 30 minutes a day at room temperature.
- EGRIFTA WR (tesamorelin) – US label, DailyMed: keep the mixed vial at 20–25 °C, do not refrigerate, discard 7 days after mixing.
- OZEMPIC (semaglutide) – US label, DailyMed: 56 days after first use, refrigerated or at 15–30 °C.
- WEGOVY (semaglutide) – US label, DailyMed: single-dose pen up to 28 days at 8–30 °C before the cap is removed; FlexTouch 56 days after first use.
- MOUNJARO (tirzepatide) – US label, DailyMed: single-dose pen or vial 21 days in total unrefrigerated; KwikPen or multi-dose vial 30 days after first use or 4 weekly doses.
- ZEPBOUND (tirzepatide) – US label, DailyMed: the same 21-day and 30-day rules as Mounjaro.
- VICTOZA (liraglutide) – US label, DailyMed and SAXENDA (liraglutide) – US label, DailyMed: 30 days after first use, refrigerated or at 15–30 °C.
- TRULICITY (dulaglutide) – US label, DailyMed: each single-dose pen up to 14 days in total at up to 30 °C.
Related tools
- Peptide storage and shelf life – why the numbers disagree and what degrades a peptide in solution.
- Vial longevity calculator – how many doses a vial holds and what each one costs.
- Peptide reconstitution calculator – how much water to add and how many units to draw.
- hCG dose calculator – IU to syringe units for a mixed hCG vial.
- Peptide pen calculator – whether a cartridge runs out before its date does.