Handling & safety guide · chapter 04

Warning signs: when to throw it out

A checklist for dry powder, mixed liquid, vials over time, and the injection site afterwards: what is normal, what means discard, and what means see a doctor.

General information, not medical advice. Approved drugs: follow your prescriber and the product's instructions for use.

One rule covers every list on this page: if any box is ticked, or you are not sure, discard the vial. A vial costs money. An abscess, a bloodstream infection or an unknown dose costs more. The CDC's instruction to clinics applies equally at home: discard a vial "whenever sterility is compromised or questionable" [1].

A clean-looking vial is not proof of anything. Bacterial contamination, chemical breakdown and wrong contents are usually invisible. These checks catch the obvious failures only.

1. Dry powder: before you mix

Discard if any of these is true:

  • The vial is cracked or chipped, or the metal crimp or stopper is loose
  • The flip-off cap is missing, or the stopper already shows a needle hole
  • There is no label, the label is unreadable, or it does not state the substance and the amount
  • The expiry date has passed
  • There is liquid or visible moisture inside a vial that should be dry
  • The contents look wet, sticky or melted
  • The powder is an unexpected colour (most peptide powders are white to off-white; a few, such as copper-containing peptides, are naturally coloured)
  • You can see dark specks, fibres or anything that is not powder
  • It arrived hot, or you do not know how it was stored (see storage)

Not a reason to discard on its own: the powder is a solid "cake", a loose powder, or a thin film on the glass. Freeze-dried products vary in appearance, and a small amount can be hard to see at all.

2. Liquid: after mixing, and before every dose

Approved labels describe what a usable peptide solution looks like: clear, free of particles, and colourless (or the colour the label states), and not frozen [2][3]. The diluent's own label says to inspect anything mixed with it for clarity, unexpected precipitation and discolouration before use [4]. General patient guidance says the same: do not use medicine that has changed colour, has small pieces floating in it, or is cloudy [5].

Discard if any of these is true:

  • Cloudy, milky or hazy, and still not clear after standing a few minutes
  • Particles, flakes, crystals, fibres or anything floating or settled
  • Jelly-like strands or a gel
  • A colour it should not have, or a change in colour since it was mixed
  • Powder that will not fully dissolve (see troubleshooting)
  • Bits of grey or dark rubber from the stopper in the liquid
  • It has been frozen, even if it looks normal after thawing [2][6]

Usually harmless: small air bubbles, or a thin layer of foam that clears when the vial is left to stand.

3. Over time: every time you take the vial out

Discard if any of these is true:

  • It is past the product's labelled in-use period
  • There is no labelled period and it is more than 28 days since a preserved vial was first punctured [1][7]
  • It was mixed with plain (unpreserved) sterile water and has already been used once [1][7]
  • There is no mixing date on the vial and you cannot remember it for certain
  • It was left out of the fridge for hours, got hot, or you do not know how long it was out
  • A needle was left sitting in the stopper (this gives bacteria a direct route in) [1]
  • The stopper is leaking, torn, or badly chewed up by repeated punctures
  • The stopper was touched or wiped with something that was not a fresh alcohol swab, then punctured
  • A used needle or syringe went back into the vial
  • Anyone else has drawn from this vial for themselves
  • The liquid now fails any check in list 2

4. After an injection: your body

Usually normal (watch, no action needed):

  • A brief sting or burn during the injection
  • A drop of blood or clear fluid at the site
  • A small bruise
  • Mild redness, itching or a small raised bump at the site that fades within a day or two. Injection-site reactions are listed among the common side effects of approved injectable peptides [3][8][9].

See a doctor or pharmacist soon (within a day or two; stop injecting until you have):

  • Redness, swelling or pain that is still getting worse a day or two after the injection
  • The area is hot, hard, or very tender [10]
  • Pus, or a lump that feels fluid-filled
  • Itchy welts or a rash at each injection site, or a rash anywhere else
  • Lumps, dents or thickened skin where you inject repeatedly (see site rotation in injection basics) [2]
  • Any new symptom you cannot explain since starting

Get medical help today, or call emergency services (see the emergency page):

  • Redness that spreads quickly, or red streaks moving away from the site [10][11]
  • Fever or chills together with a sore injection site [10][11]
  • Swelling of the face, lips or tongue, trouble breathing, widespread hives, or feeling faint [12]
  • Severe abdominal pain, chest pain, or collapse

If you discard

Do not pour it down the sink and reuse the vial, and do not keep it "just in case". Dispose of the vial and any used syringe as described in disposal. If the product is an approved medicine from a pharmacy, tell the pharmacy: they may replace it and they can report a defect.

Sources

Checked 13 November 2026.

  1. U.S. Centers for Disease Control and Prevention. "Preventing Unsafe Injection Practices." https://www.cdc.gov/injection-safety/hcp/clinical-safety/index.html
  2. Tirzepatide (Zepbound) single-dose vial, Instructions for Use (revised April 2026). (link not shown: non-primary host)
  3. Tesamorelin for injection (Egrifta WR), US prescribing information and instructions for use, DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75
  4. Bacteriostatic Water for Injection, USP (0.9% benzyl alcohol), US product labeling. (link not shown: non-primary host)
  5. MedlinePlus Medical Encyclopedia. "Drawing medicine out of a vial." https://medlineplus.gov/ency/patientinstructions/000530.htm
  6. Nugrahadi PP, Hinrichs WLJ, Frijlink HW, Schöneich C, Avanti C. "Designing Formulation Strategies for Enhanced Stability of Therapeutic Peptides in Aqueous Solutions: A Review." Pharmaceutics. 2023;15(3):935. https://doi.org/10.3390/pharmaceutics15030935
  7. American Society of Health-System Pharmacists. "The Pharmacist Guide to Assigning a Beyond-Use Date to a Compounded Sterile or Nonsterile Preparation" (summarising USP <797>). https://www.ashp.org/-/media/assets/pharmacy-practice/resource-centers/compounding/docs/The-Pharmacist-Guide-to-Assigning-a-Beyond-Use-Date.pdf
  8. Tirzepatide injection (Zepbound), US prescribing information, DailyMed. https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b&type=display
  9. Bremelanotide injection (Vyleesi), US prescribing information, DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf
  10. U.S. Centers for Disease Control and Prevention. "About Cellulitis." https://www.cdc.gov/group-a-strep/about/cellulitis.html
  11. MedlinePlus Medical Encyclopedia. "Subcutaneous (SQ) injections." https://medlineplus.gov/ency/patientinstructions/000430.htm
  12. MedlinePlus Medical Encyclopedia. "Anaphylaxis." https://medlineplus.gov/ency/article/000844.htm