Insulin in practice — the first two weeks become a lifelong craft

You leave the clinic holding a vial of insulin and a bag of syringes. At home, opening that bag, the heart drops — "me? twice a day? into this cat?"

First things first: you can. Hundreds of thousands of caregivers do it every day, and most arrive within two weeks at "that was easier than I feared." The needle is hair-thin, and most cats never notice past their treat. This article is the complete craft of those two weeks — with the three safety rules that prevent 90% of accidents set in bold along the way.

1. For the needle-afraid caregiver — the craft of the first two weeks

• The first injection happens at the clinic — give one (ideally two) in front of the vet before going home. Once the hands remember, home fear halves
• Build a ritual — same time, same spot, same order: meal → treat ready → injection → treat. Within two weeks, cats that show up on their own at injection time are not rare
• Your tension is contagious — one deep breath beats a trembling hand. For the first days, work in pairs (one person on treats) and the difficulty drops sharply
• Does it hurt? — insulin needles (29–31 gauge) are finer than lancets; done properly, most cats show no reaction at all. If yours reacts, it is usually to being held, not to pain — so the fix is the ritual, not the restraint

2. The insulin catalogue — knowing what is in your hand

3. Storage and handling — housekeeping that protects potency

• Refrigerate (2–8°C); never freeze — insulin that has frozen is discarded. The back of the fridge is steadier than the door shelf
• Suspensions (cloudy insulins) are rolled between the palms, never shaken — shaking damages the protein. Glargine is a clear solution needing no mixing — and if it turns cloudy, that vial is done
• In-use life — the label says 28 days, but with feline micro-doses, veterinary practice commonly uses refrigerated vials much longer (months). Ask your clinic's rule and follow it — and when potency inexplicably fades, suspect the old vial first
• Bubbles — stand the syringe upright, tap them to the top, push them out. At tiny doses, a bubble is a real error
• Travel — cooler bag with an ice pack (a towel between; no direct contact). Some pens specify room temperature while in use — check the product

4. The injection itself — six steps

1. Meal first — confirm eating, then inject. If the cat will not eat, do not inject; follow your vet's rule (half or skip, plus a call). Empty stomach + insulin = the hypoglycemia formula
2. Draw the dose — good light, markings at eye level; roll suspensions first
3. Pick the site — the scruff is easy to grab but can absorb slowly; the recommendation is to rotate along the flanks and sides, a new spot each time. Repeated same-site injections build lumps (granulomas), and lump tissue absorbs insulin poorly — one cause of "it worked, then suddenly it doesn't"
4. Tent the skin — lift a triangle of skin with thumb and forefinger and enter the side wall of the tent at 45° — without passing through to the far side (a through-and-through leaves wet fur)
5. Push, withdraw — inject slowly, withdraw straight, no rubbing
6. Treat — always, regardless of how it went. The ritual builds the next injection

5. The study of failure — the rules for when it goes wrong

• The 12-hour rhythm, with slack — aim for 12-hour spacing; in real life ±1–2 hours is usually tolerable (your cat's own margin: ask the vet). Later than that, skip the round and rejoin at the next scheduled time — never compress the interval to catch up
• Vomiting — vomited before the shot: apply the meal-and-dose rule you agreed with the clinic (usually half/skip). Vomited after the shot: the insulin is already in and cannot be recalled — switch to low-sugar watch mode (spot checks, honey on standby) and call
• Syringe reuse and disposal — single-use is the rule (dull needles hurt). Collect used syringes in a thick plastic container and hand them to the clinic for disposal

6. The dose — the caregiver's role, and what is not

• Start low, go slow — adjustments usually come at 1–2-week intervals, in small steps. Responses take days to settle; daily fiddling leads into a maze
• A high morning number ≠ automatic increase — it may be rebound after an unseen overnight low, or the insulin running out early. Only a curve (or a Libre) can tell those apart — which is why "since when has it been high?" precedes "raise it"
• The falling-requirement signal (same dose, ever-lower numbers) is the signal of the remission chapter — never miss it, always share it

7. What to ask your vet

• "Is this insulin U-40 or U-100 — and do these syringes match?"
• "How long do we use an opened vial, by this clinic's rule?"
• "Please write down the rules for a day she won't eat, or eats half"
• "How many hours can the injection time safely drift?"
• "Could you watch one more practice injection now — site rotation included?"
• "Is this a dose where half-unit syringes would help?"

8. Related

• Measuring glucose at home — the pre-injection spot check, this chapter's partner
• Feeding — why the meal and the injection are one body
• The day of diagnosis — the honey drill, memorised before any injection technique
• The Diabetes Bible — contents — chapter 08, the crises, is this chapter's emergency exit