Toujeo can be left out of the refrigerator for up to 28 days, as long as the temperature stays below 86°F (30°C). This applies to both opened pens you’re actively using and unopened pens that have been taken out of the fridge. After 28 days at room temperature, the pen should be discarded regardless of how much insulin remains inside.
Storage Rules for Unopened vs. In-Use Pens
Unopened Toujeo SoloStar pens belong in the refrigerator at 36°F to 46°F (2°C to 8°C) until you’re ready to use them. Refrigerated pens stay good until the expiration date printed on the packaging. Once a pen leaves the fridge, whether you’ve used it or not, the 28-day countdown begins.
Once you start using a Toujeo pen, do not put it back in the refrigerator. The FDA-approved prescribing information is explicit on this point: opened pens should be kept at room temperature only, below 86°F (30°C), and away from direct heat and light. Refrigerating an in-use pen can cause temperature fluctuations that affect the insulin.
What Counts as “Room Temperature”
Room temperature for Toujeo means anything below 86°F (30°C). That’s a comfortable indoor environment for most homes, but it’s easy to exceed that threshold in certain situations. A car parked in the sun, a bag left on a sunny windowsill, or an un-air-conditioned room during summer can all push well past 86°F. At those temperatures, the insulin can break down and lose its effectiveness without any visible change to the liquid.
Freezing is equally damaging. If a Toujeo pen freezes at any point, it should be thrown away. Never store it directly on ice or against a gel pack in a cooler.
How to Tell if Toujeo Has Gone Bad
Toujeo is a clear, colorless solution. Before each injection, take a quick look at the liquid in the pen. If it appears cloudy, discolored, or contains visible particles or clumps, the insulin has degraded and should not be used. That said, heat damage doesn’t always produce visible changes. If you know a pen has been exposed to temperatures above 86°F or has been out of the fridge for more than 28 days, discard it even if the liquid looks normal. Unexplained high blood sugar readings can also be a sign that your insulin has lost potency.
Keeping Toujeo Safe During Travel
Traveling with Toujeo requires a bit of planning, especially in warm climates. An insulated cooling case or pouch designed for insulin is the simplest solution. These keep pens within a safe temperature range for hours without electricity. If you’re using a cooler with ice packs, wrap the pen in a cloth or towel so it never touches the ice directly.
The CDC recommends never leaving insulin or diabetes equipment in a hot car, even briefly. Dashboard temperatures can exceed 150°F on a sunny day. If you’re flying, pack your Toujeo in a carry-on bag rather than checked luggage, since cargo holds can drop below freezing at altitude.
For longer trips, keep unopened backup pens refrigerated whenever possible. Hotel mini-fridges work fine as long as you place the pens away from the back wall or any freezer compartment, where temperatures can dip below safe levels. If refrigeration isn’t available, your unopened pens follow the same 28-day rule as opened ones from the moment they leave cold storage.
What Happens if You Exceed 28 Days
Insulin that has been at room temperature for longer than 28 days may not lower your blood sugar effectively. The protein structure of the insulin gradually breaks down with time and heat exposure, reducing its potency. You won’t necessarily feel different after injecting degraded insulin, but your blood sugar readings will trend higher than expected. If you notice your levels creeping up and you’ve been using the same pen for close to a month, switching to a fresh pen is a reasonable first step before adjusting your dose. Return expired or degraded pens to your pharmacy for proper disposal rather than tossing them in household trash.