A dry shipper is a vacuum-insulated container that keeps frozen embryos, eggs and sperm at about -196°C during transport. Its inner walls soak up liquid nitrogen like a sponge, so the specimens stay in ultra-cold nitrogen vapor while there is no free liquid that can spill. That is what makes a dry shipper safe to move by car or carry onto a plane.
Below, our embryologist-led team explains how a liquid nitrogen dry shipper works, how long it stays cold, and what to ask before your own specimens travel in one.
What is a dry shipper?
A dry shipper is a cryogenic transport container built to hold biological material at liquid nitrogen temperature without carrying any loose liquid nitrogen.
From the outside it looks like a heavy, oversized thermos. Inside, a narrow chamber holds the canister with your straws or vials. Around that chamber sits a thick layer of absorbent material, and around that, a vacuum jacket that keeps outside heat from getting in.
The word “dry” does not mean the container is warm or empty. It means the liquid nitrogen has been fully absorbed, so if the shipper tips over, nothing pours out.
How does a liquid nitrogen dry shipper work?
A dry shipper works by storing liquid nitrogen inside its walls and letting it slowly turn into cold vapor around the specimens.
1. Charging
Before a mission, the shipper is filled with liquid nitrogen and left to soak. The absorbent lining takes up the nitrogen until it is saturated. Any liquid that is not absorbed is poured off.
2. Holding in vapor phase
As the absorbed nitrogen evaporates, it fills the inner chamber with nitrogen vapor close to -196°C. The specimens sit in this vapor, not in liquid.
3. Insulation and venting
The vacuum jacket slows heat transfer dramatically. A vented lid lets the evaporating gas escape safely, so pressure never builds up inside.
Dry shipper vs. liquid nitrogen tank: what’s the difference?
The difference is free liquid: a storage tank holds pooled liquid nitrogen, while a dry shipper holds none.
- Storage tank (dewar): holds specimens in or above pooled liquid nitrogen. Built for long-term storage in a lab, not for travel.
- Dry shipper: all nitrogen is absorbed into the walls. Built for transport, because it cannot spill.
This is why specimens are moved from the clinic’s storage tank into a charged dry shipper right before pickup, and back into the receiving clinic’s storage tank on arrival.
Can you fly with a dry shipper?
Yes. A properly charged dry shipper can travel on passenger flights, because it contains no free liquid nitrogen.
Under international air-transport rules, a dry shipper with fully absorbed nitrogen is generally not treated as dangerous goods. Individual airlines and airports can still have their own procedures, so a courier who travels with dry shippers regularly will know what each route requires.
Security screening matters too. At LifeParcel, specimens are never put through X-ray screening. You can read why in our guide to what X-rays can do to fertility specimens.
How long does a dry shipper stay cold?
The dry shippers we use hold -196°C for up to 21 days once fully charged.
That is far longer than a typical LifeParcel mission, which takes 3 to 4 days door to door. The extra margin is what protects your specimens if a flight is cancelled or paperwork takes longer than planned.
Real-world hold time depends on a few things:
- The size and model of the shipper
- How completely it was charged before the trip
- How many times the lid is opened (each opening lets cold vapor out)
- Whether it is kept upright and handled gently
For more on timing, see how long eggs, sperm and embryos can safely travel.
Why the temperature has to stay at -196°C
Frozen embryos, eggs and sperm stay viable only as long as they remain at cryogenic temperature.
At -196°C, cell activity effectively stops. If the temperature rises too far, even briefly, ice can form inside the cells and damage them. That is why the shipper, the handling and the monitoring all matter. Our article on why every degree matters in IVF transport explains this in more detail.
How temperature is monitored during transport
A data logger inside or on the shipper records the temperature for the whole journey.
At LifeParcel, every mission has 24/7 GPS and temperature logging. After delivery, a temperature report is available on request, so the receiving clinic and the patient can see that the specimens stayed cold from start to finish.
Hand-carry vs. sending a dry shipper as cargo
A dry shipper can travel two ways: carried by a dedicated courier, or sent as cargo through commercial cryoshipping networks.
With commercial cryoshipping, the tank moves through sorting facilities and cargo holds, often passing through several hands. With hand-carry, one dedicated courier keeps the shipper in sight from pickup to delivery. There are no handoffs, the shipper stays upright, and the courier can respond immediately if a flight changes.
We compare both options in hand-carry vs. commercial cryoshipping.
Questions to ask your transport provider about dry shippers
Before you book, ask any provider these five questions:
- What model of dry shipper will you use, and what is its hold time?
- When is it charged, and who checks it before pickup?
- Is the temperature logged for the whole journey, and can I get the report?
- Will one person stay with the shipper the entire way, or does it travel as cargo?
- What is the plan if a flight is cancelled or the shipment is held?
Clear, specific answers are a good sign. Vague answers are a reason to keep looking.
How LifeParcel handles dry shippers
LifeParcel is an embryologist-owned international IVF courier with more than 3,200 missions across 32+ countries.
- One dedicated courier keeps the shipper in sight from pickup to delivery
- 24/7 GPS and temperature logging, with a temperature report on request
- No X-ray screening, ever
- We have never had to open a tank at customs
If you are planning a transfer, you can request a quote and we will reply within 24 hours.
Frequently asked questions
What is a dry shipper used for?
A dry shipper is used to transport frozen biological material, such as embryos, eggs, sperm and reproductive tissue, at about -196°C without free liquid nitrogen.
Is a dry shipper the same as dry ice?
No. Dry ice is frozen carbon dioxide at about -78°C, which is far too warm for frozen embryos, eggs or sperm. A dry shipper uses liquid nitrogen and holds about -196°C.
Does a dry shipper contain liquid nitrogen?
Yes, but it is fully absorbed into the shipper’s inner walls. There is no free liquid, which is why it can’t spill and can travel on passenger flights.
How long can specimens stay in a dry shipper?
The dry shippers we use hold -196°C for up to 21 days, while a typical mission takes 3 to 4 days. You can find more answers on our FAQ page.
Planning to move embryos, eggs or sperm between clinics? Request a quote and our team will get back to you within 24 hours.
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