Research library / Guides
Why dry vials travel without cold packs, and what to do when yours arrive.
No. Lyophilized peptides are dry powder, which handles normal transit at room temperature, so they ship without ice. Heat and moisture still matter over longer periods, so move your vials somewhere cool, dry and dark when they arrive.
01
Why can dry peptides travel without ice?
Water drives many of the reactions that break peptides down. Freeze-drying removes most of it, which leaves the peptide in a far more stable solid. A 1999 study of a freeze-dried test peptide found that one breakdown reaction, deamidation, ran faster as the water content rose.
Mixed vials are different. Once dissolved, a peptide sits in water full time and belongs in the fridge: how to store peptides.
02
What does the research show?
The closest public data we know of is a 2015 FDA laboratory study of a freeze-dried peptide hormone, secretin, which is labeled for storage at −20 °C. Vials were kept at −20 °C, 4 °C, 25 °C, and 25 °C with 60% humidity, then tested at 1, 4 and 8 weeks. Measured content had dropped by week 8, and in the warm, humid condition particles had grown by week 1.
So time, heat and humidity all count, and long-term stock belongs somewhere cold and dry.
That study covers one peptide, and it is not one we sell. We know of no published shipping study on the compounds in our catalog, so we can’t give you a tested temperature limit for a hot day.
03
How does Prism Labs ship?
Orders placed before 4:30 PM Central ship the same day, seven days a week. UPS Ground is estimated at 1 to 5 business days, and UPS 2nd Day Air at 2. Each vial is bubble-wrapped, and we don’t add ice or cold packs.
In summer heat, 2nd Day Air shortens the trip.
04
What should I do when my vials arrive?
Check them first, then store them:
- Expect very little powder. 10 mg is a tiny amount, so a vial can look almost empty.
- Clumps, or powder on one side of the vial, are normal after shipping. They should dissolve once mixed.
- A cracked, open or leaking vial is not normal. Contact support within 48 hours of delivery, with photos.
- Store unopened vials somewhere cool, dry and dark. Many labs keep long-term stock at −20 °C.
- Let a cold vial reach room temperature before you open it, so moisture does not condense on the powder.
A little more clarity
Questions, answered
Do peptides need to be refrigerated during shipping?
Not as dry powder. Lyophilized peptides handle normal transit at room temperature. Mixed peptides are a different matter and belong in the fridge.
What if my peptides sat in a hot mailbox?
Bring them inside and store them somewhere cool. No published study we know of sets a limit for these compounds, so contact support if a vial is damaged or looks wrong.
How long can lyophilized peptides stay at room temperature?
There is no single figure, because it depends on the peptide. Short periods such as shipping are fine; for long-term storage, keep them cold and dry.
Should I put unopened vials in the freezer?
For long-term stock, many labs do, at −20 °C. For the short term, somewhere cool, dry and dark is enough.
Are Prism Labs peptides for human use?
No. Prism Labs sells them for laboratory research use only.
Follow the evidence
Sources & reading notes
Open the original record for its methods and limitations. The sources below do not certify the supplied product or its finished formulation.
- Journal of Pharmaceutical Sciences · 1999 ↗
Water content speeds deamidation of a peptide in dry solids.
- International Journal of Pharmaceutics · 2015 ↗
FDA laboratory study of storage temperature and humidity on a freeze-dried peptide, secretin.
Prepared by Prism Labs from the linked source records and public product documentation. Research context only; not a preparation protocol or a claim about outcomes. Send a source correction.
Keep exploring
More from the research library.
How to store peptides
What water, heat, light and repeated freezing do to a peptide, and how to limit each.
Read the article ↗GuidesHow to reconstitute peptides
Seven steps from dry powder to a clear, labeled vial, plus the concentration math.
Read the article ↗Guides
How to read a peptide COA
Three results, three different questions. Read them separately.
Read the article ↗