Refrigerating insulin is essential to maintain its effectiveness before use. However, while most people with diabetes know the importance of storing insulin at the correct temperature, there is still some confusion about whether it is safe to inject cold insulin.

So, let's finally answer that critical question: "Can you inject cold insulin straight from the fridge?". And, most importantly, what happens if you do?
4AllFamily Insulin Coolers and Organizers for Diabetics

Can you Inject Cold Insulin?

While your unopened insulin pens, vials, and cartridges must be kept refrigerated at 36°F to 46°F (2°C to 8°C), it is not recommended to inject insulin straight from the fridge.
Indeed, cold insulin can increase pain or discomfort during the injection. It's a matter of comfort rather than safety, as cold insulin is as effective as room-temperature insulin. Therefore, when cold insulin is the only available option, you can safely inject it.
Related article: 10 Tips That Work to Inject Insulin Without Pain!

Why is injecting cold insulin more painful?

When injecting insulin straight from the fridge, some people report suffering from a stinging or burning sensation at the injection site. Generally, this type of discomfort lasts for a few seconds or minutes only.
There are several reasons why injecting cold insulin may be more painful. First, the liquid may be more viscous or thicker than insulin that has been stored at room temperature.
The coldness may also cause the tissue at the injection site to react and contract, leading to increased resistance and pain during the injection.
Another explanation could be that cold insulin may take longer to absorb into the bloodstream, leading to increased discomfort for the patient. However, there's no study on that specific point.
Related article: What are the Best Insulin Injection Sites?

Is cold insulin less effective?

Cold insulin that has been kept at the recommended fridge temperature between 36°F and 46°F (2°C and 8°C) is not less effective. Quite the opposite in fact, as refrigeration is the only way to maintain and prolong insulin’s efficacy.
However, be aware that insulin loses effectiveness when exposed to extremely cold temperatures. When frozen, insulin solution becomes crystals that break the molecule. Once it has frozen, insulin isn’t safe for use anymore, even if it has thawed afterward. Therefore, it’s essential to ensure your insulin never freezes!
Insulin freezing point is the same as water: 32°F (0°C). To maintain a safety margin, insulin should never be exposed to temperatures under 36°F (2°C).
That’s why our insulin travel coolers are equipped with anti-freeze security!
Insulin Travel Coolers by 4AlLFamily

Should you warm insulin before injecting?

When taking a new bottle or pen of insulin straight from your refrigerator, you can gently warm it up to prevent pain during the injection.
Roll the vial or pen between your palms, or let it sit at room temperature for a few minutes before injecting. But never warm insulin in any other way, such as with a microwave or hot water, as exposure to hot temperatures can quickly spoil your medicine!

Related article: How to Tell if Your Insulin Has Gone Bad?

Why Should Insulin Be Stored Cold?

All types and brands of insulin should be stored in the refrigerator before first use, including Lantus, Novolog, Humalog, Levemir, and others.
Insulin is a protein hormone that quickly becomes unstable and breaks down when exposed to heat or extremely cold temperatures, affecting its effectiveness and ability to lower blood sugar levels.
Following insulin manufacturers' storage instructions is essential. Failure to do so can seriously affect the quality of your injection and, ultimately, the success of your therapy and diabetes management.

How long can insulin be unrefrigerated?

Fortunately, most insulins allow for flexibility as they can stay unrefrigerated for a few days or weeks once opened. For example:

  • Lantus, Novolog, and Humalog can be kept at room temperature (below 86°F / 30°C) for 28 days.
  • Levemir can stay at room temperature for up to 42 days.
  • Premixed insulins can generally be unrefrigerated for 7 to 14 days only.

How to Avoid Pain When Injecting Insulin? 

Insulin needles and syringes have considerably improved in recent years. Today’s needles are much smaller and thinner than they used to be, with sharper and more lubricated tips.

Unfortunately, some people never get used to insulin injections and still experience pain and discomfort.

Besides allowing cold insulin to reach room temperature, a few tips may help reduce pain and discomfort during the injection:

  • Choose the right insulin needle size
  • Never reuse insulin pen needles or syringes
  • Gently massage the injection site before the injection
  • Always rotate injection sites before each shot
  • Insert the needle at a 90-degree angle in a quick motion
  • Dry your skin before the injection
  • Relax and breathe deeply
  • Consider using injection pain-reducing tools like the Medtronic I-Port Advanced or the ShotBlocker by Bionix.

Related article: How Does Mounjaro Work for Diabetes and Weight Loss?

Do you find insulin injections painful? Have you noticed that injecting cold insulin straight from the fridge tends to be more painful?
April 04, 2023

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The information presented in this article and its comment section is for informational purposes only and is not intended as a replacement for professional medical advice. Always consult with a qualified healthcare provider for any medical concerns or questions you may have.