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Lost or damaged insulin

Damaged insulin usually looks normal, so circumstances decide rather than inspection. The UK routes to a replacement today, and what not to do while you wait.

Written by Updated 5 December 2025 6 min read
The 60-second answer

Insulin gets left on trains, dropped on tiled floors, cooked in cars and frozen in coat pockets. The two questions are always the same: is this insulin still usable, and how do I replace it today. In the UK the second question has a proper answer.

  • Damaged insulin usually looks normal. You cannot inspect your way to confidence.
  • If you genuinely suspect heat, freezing or a hard knock, treat that one as finished.
  • NHS 111 runs an emergency prescription service for a regular repeat medicine.
  • A pharmacy can supply an emergency amount at their discretion. Bringing the box or a photo makes it far easier.
  • Never ration what is left to make it stretch. Ask for help sooner instead.
Is it usable

What damage looks like, and what it does not

Sometimes there is a visible sign. Insulin that should be clear turning cloudy, clumps, floating particles, or a frosted appearance inside the cartridge all mean that one is finished. So does a cracked cartridge or a pen that has obviously been damaged.

Far more often there is nothing to see. Insulin that has been too hot or has frozen loses strength while looking exactly as it always did, which is why the honest advice is about circumstances rather than inspection. If a pen spent an afternoon in a hot car, went through a freezing night in a coat, or came out of a hold on a flight, the sensible assumption is that it may be affected.

A drop onto a hard floor is its own case. If the cartridge is intact and nothing is leaking it is usually fine, and if there is any crack or any leak it is not. Pens can also be damaged internally by a hard knock without showing it, so a pen that starts behaving oddly after being dropped is worth replacing rather than persevering with.

The behavioural clue is the one that catches people. Insulin that seems to be doing nothing, with your sites, technique and routine unchanged, is one of the ordinary explanations for a stretch of unexplained highs. That is worth telling your team about rather than adjusting around, because insulin changes are worked out with your diabetes team.

Replacing it

The routes, in the order to try them

Your GP is the normal route if there is time. A phone call explaining that insulin has been lost or damaged is usually enough for an urgent prescription, and most practices will handle it the same day, particularly if you make clear this is insulin rather than a routine reorder.

Out of hours, or when the practice is closed, NHS 111 operates an emergency prescription service specifically for people who have run out of a regular repeat medicine. It exists for exactly this and it is not an imposition to use it.

A pharmacy can also supply an emergency amount of a prescription medicine at the pharmacist’s discretion, which is often the fastest route of all if you can get to one. Take the box, an old pen, a repeat slip or a photograph of the packaging, because the pharmacist works from the exact name and strength rather than from a description.

All of these depend on knowing what you take. This is the practical reason for keeping a photo of your boxes on your phone, and it is worth doing before you need it rather than trying to remember a name in a chemist. If you are abroad the routes are different and we cover those separately in problems getting supplies abroad.

The gap

What not to do while you wait

The instinct when supplies are short is to make them last, and it is the wrong one. Reducing your insulin to stretch a supply puts you back toward the state you were in before diagnosis, and ketones can build within hours rather than days. If you are short, that is a reason to seek help sooner, not to manage it quietly.

Contact your diabetes team early too, especially if the gap might be more than a few hours or if you are a pump user, since a pump user has no long-acting insulin behind them and a supply problem becomes urgent much faster. If you are unwell as well as short, treat it as urgent rather than administrative, and ring 111 or your team.

Afterwards, it is worth a moment to make the next one easier. Holding more stock than you strictly need, splitting supplies rather than keeping everything in one bag, and keeping a photo of your boxes are all small habits that turn this from a crisis into a phone call. Most people learn them by having exactly one bad afternoon.

What varies

What decides how serious it is

Which insulin has gone matters most: losing your long-acting is a faster problem than losing mealtime insulin, and a pump user losing supplies is faster again. Bank holidays are the practical one, since a Friday problem can become a four day problem. And being unwell at the same time moves the whole thing from admin to urgent.

how much you have leftwhether it is your background insulinpump or penstime of daya weekend or bank holidayhow far you are from homewhether you are also unwell
Real-life examples

How it happens

Examples, not instructions or doses.

The afternoon in the car

A pen left on a passenger seat in July, looking completely unchanged afterwards. Circumstances rather than inspection decide this one.

The tiled bathroom floor

A dropped pen with no visible damage that started behaving oddly. Internal damage does not always show.

The bag left on the train

Everything in one place and none of it recoverable. A pharmacy or 111 can sort it, and a photo of the boxes makes it quick.

What to notice

Worth paying attention to

That damaged insulin usually looks completely normal, so circumstances rather than inspection decide whether to bin it
That cloudiness, clumps, particles or frosting mean that one is finished, as does any crack or leak
That insulin apparently doing nothing, with nothing else changed, is worth telling your team about
That NHS 111 runs an emergency prescription service, and a pharmacist can supply an emergency amount at their discretion
Taking the box, an old pen or a photo of the packaging, since a pharmacist works from the exact name and strength
Never rationing what is left to make it stretch, and contacting your team early if the gap could be more than a few hours
What to ask your team

Questions that make an appointment useful

"I think my insulin got too hot or frozen, should I be using it?"
"What should I do if I lose my insulin at a weekend?"
"How much spare stock should I be holding?"
"My insulin seems to have stopped working properly, what should I be looking at?"
"As a pump user, how quickly does a supply problem become urgent for me?"
Sources