Short answer: in the US you can carry refrigerated vials and medication through the checkpoint in your carry-on, with frozen or partly frozen gel packs, as long as you declare them and let the officer screen them. The rest of this page is the rule as TSA writes it, how to keep a case cold for a day of travel, and how to find out whether your setup actually worked.
What the TSA rule says
We quote the TSA's own words rather than paraphrase them, because most of what is written about this on shopping pages is slightly wrong.
TSA allows larger amounts of medically necessary liquids, gels, and aerosols in reasonable quantities for your trip, but you must declare them to TSA officers at the checkpoint for inspection.
Source: tsa.gov, What Can I Bring: Medical
Ice packs, freezer packs, gel packs and other accessories may be presented at the screening checkpoint in a frozen, partially frozen or melted state to keep medically necessary items cool.
Source: tsa.gov, TSA Cares: Disabilities and Medical Conditions
The final decision rests with the TSA officer on whether an item is allowed through the checkpoint.
Source: tsa.gov, Medications (Liquid)
In plain words: the 3.4 oz (100 ml) limit does not apply to medically necessary liquids, you tell the officer before screening starts, you put them in a separate bin with the gel packs, and the officer has the last word. Frozen solid is the easiest to explain, but TSA says packs may be presented frozen, partially frozen or melted.
One wording point. The TSA does not approve products, so a case sold as "TSA approved" is using a phrase the TSA itself does not use. We say TSA compliant: built to be used inside this rule.
The EU rule, in plain words
Under the EU aviation security regulation (2015/1998), medicines you need during the trip are exempt from the 100 ml liquids limit. The exemption names medicines; it does not name gel packs, so whether a pack goes through is down to the screener on the day. What helps: vials in a sealed case, packs frozen solid, a short note or prescription if you have one, and a request for a manual inspection if you would rather not send vials through the X-ray. Other countries and airlines differ, and rules change, so check your own airport's page before you fly.
Three ways to keep a case cold, and what each really does
Gel packs in an insulated bag. The cheapest option and the one most people start with. Case in the middle, a frozen pack on each side, never a pack touching glass. It needs no charging and it stops working when the packs thaw. We cannot give you an honest number of hours, because it depends on the bag, the packs, the starting temperature and the room, and we have not run our own timed tests on packs. Plan on hours, not days.
A better-insulated cooler bag. Same idea with thicker walls. It stretches the same pack for longer and weighs more. It is still a countdown.
An active cooler. The VialHaus Cold is thermoelectric: it cools to a set point instead of counting down. It holds 36 to 46 F in rooms up to about 80 F, and runs warmer above that, so it is not for a parked car or a sunny window. Its built-in battery is rated at 10 to 20 hours (that is the maker's figure; we are still logging our own), and after that it runs from a wall adapter, a car USB port or a power bank. The battery is about 50 Wh, under the 100 Wh airline limit, so it goes in carry-on, never in checked baggage. How it works and where it stops is in what a thermoelectric cooler can and cannot do.
Which one for which trip
- One flight or a day out, and a fridge at the other end: gel packs in an insulated bag.
- A long travel day with connections, or several nights in places you do not control: an active cooler, with a pack as backup.
- A hotel that says it has a fridge: ask before you rely on it, and put a thermometer in it when you arrive. Many room fridges and mini-bars run warm or cycle widely. Here is how to check.
A carry-on plan
- The night before: freeze the packs flat. Put a probe thermometer in the bag with the case and a pack on each side for an hour or two at home, so you know how your setup behaves before you rely on it.
- Pack: vials upright in a hard case, the case in the insulated bag, a pack on each side. A hard case matters most here, because vials loose in a bag knock together. The 15 Vial Case and 30 Vial Case hold 3 ml vials upright; the 26 Protocol Case also takes 10 ml vials.
- At the checkpoint: tell the officer before screening starts that you have medically necessary liquids, take the bag out, and put it in a separate bin with the packs.
- In the air: keep it with you, under the seat, away from heat. Carry-on only; hold temperatures swing.
- On arrival: straight into a fridge you have checked, or into the cooler on its charger, and set a phone alarm titled VIALS IN FRIDGE for checkout day.
The card for your wallet
Every VialHaus order includes a printable travel card with the TSA and EU wording above. The same rules are on our travel page, with the date-tracking tools in the expiry calculator.
Storage accessories only. Nothing here is medical advice. Rules change; check tsa.gov and your airline before you fly.