Short answer: It depends on the product. Some labels ask for it: Lantus says to take a new pen out of the fridge at least an hour early because cold insulin hurts more, Prolia allows 15 to 30 minutes, and Evenity asks for at least 30. Others do not: Mounjaro and Zepbound say warming is not necessary, and Forteo says to inject right after taking it out. Labels that mention warming say never to use heat.
| Product | What the label says |
|---|---|
| Lantus SoloStar | Take a new pen out of the fridge at least 1 hour before injecting; cold insulin is more painful to inject |
| Prolia | May be brought to room temperature (up to 77°F) in its carton; usually takes 15 to 30 minutes; do not warm any other way |
| Evenity | Let it sit at room temperature for at least 30 minutes; do not warm any other way |
| Ozempic and Wegovy prefilled syringes | Do not warm using heat sources such as hot water or a microwave |
| Mounjaro and Zepbound pens | It is not necessary to warm the pen to room temperature |
| Forteo | Inject right away after taking the pen out of the fridge, then put it back |
The Lantus instructions give the reason directly: cold insulin is more painful to inject. Prolia and Evenity come in prefilled syringes kept in the fridge, and their labels build the wait into the steps before injecting.
For Forteo, the label goes the other way. One pen delivers 28 daily doses and goes back in the fridge after each one, so it is used cold. Mounjaro and Zepbound single-dose pens can be injected straight from the fridge.
Where a label covers warming, it rules out shortcuts. Prolia and Evenity say not to warm "in any other way" than leaving them out. The Ozempic and Wegovy syringe instructions name hot water and the microwave. The labels also set top temperatures for storage.
Room temperature in these labels means up to the stated limit, often 77°F (25°C) or 86°F (30°C). Leaving a product out longer than its label allows is a different question; see left out of the fridge.
The wait is a natural time to read the label and look at the medicine. The Evenity label asks for a check for particles and discoloration and of the expiration date, and the Prolia label asks for a visual check for particles and discoloration. Product-by-product details are on the Prolia, Evenity and Lantus storage pages.
If a product is not in this list, its own Instructions for Use is the place to look, or ask the pharmacist. Dose Track keeps each pen or vial with its open date, which helps with the room-temperature day limits some products carry.
Read more on Dose Track: Left out of the fridge · How to use an injection pen · Sub-Q injection guide · Vials and inventory in Dose Track