What Happens If You Don't Refrigerate B12?

November 17, 2025 •

4 min read

While most oral vitamin B12 supplements are stable at room temperature, certain formulations, particularly B12 injections and specific liquid or sublingual drops, require refrigeration to maintain their potency and prevent degradation. Failing to properly store these specific types of B12 can compromise their effectiveness and potentially create safety concerns.

Quick Summary

Different B12 product types have varying storage requirements. Improperly storing injectable, liquid, or certain sublingual B12 formulations can lead to a loss of potency, reduced effectiveness, and potential safety risks, though most oral tablets are stable at room temperature. Always check product labels for specific instructions.

Key Points

Check the Label: Always read the product label, as refrigeration is necessary only for specific B12 formulations, not all of them.
Injectables Require Refrigeration: B12 injections must be refrigerated to maintain potency and prevent bacterial growth.
Heat Causes Degradation: Heat exposure can break down vitamin B12 molecules, reducing the supplement's effectiveness over time.
Visible Signs of Spoilage: A change in color or cloudiness in liquid or injectable B12 is a clear sign of spoilage, and the product should be discarded.
Prioritize Safety: If an injectable B12 vial has been left unrefrigerated, consult a pharmacist before use to ensure it is still safe.
Store Oral Supplements Properly: Even shelf-stable B12 tablets should be kept in a cool, dry place away from direct heat and moisture.

The Importance of Proper Vitamin Storage

Maintaining the efficacy and safety of medications and supplements is paramount, and storage conditions play a crucial role. Environmental factors like heat, light, and humidity can break down delicate chemical compounds, diminishing a product's intended benefits. For certain sensitive products like specific forms of vitamin B12, strict storage rules are non-negotiable. It is critical to differentiate between the storage needs of common oral tablets and more sensitive formulations like injectables.

B12 Injections: The Non-Negotiable Need for Refrigeration

For many B12 injections, proper refrigeration is absolutely vital and not just a suggestion. Heat can denature and destroy the vitamin molecules, rendering the injection less effective or completely useless. The typical refrigerated temperature range is between 2°C and 8°C (36°F to 46°F), as recommended by many manufacturers. Without this controlled cold environment, the product can degrade quickly. Furthermore, refrigeration also helps prevent the growth of bacteria within the vial, which is a serious safety concern when injecting a substance into the body.

What Happens to Injectable B12 at Room Temperature?

If a B12 injection vial meant for refrigeration is left out, several things can happen:

Loss of Potency: The vitamin molecules can begin to break down, meaning that each dose will contain less active B12 than intended. This can lead to a user not receiving the full therapeutic benefit, which is especially problematic for those with a significant deficiency.
Visible Changes: In some cases, the liquid may change in appearance. It could become cloudy, thicken, or change color. Any visible alteration is a clear sign that the product is no longer safe or effective and should be discarded.
Bacterial Contamination: Temperature fluctuations and warmer environments can encourage bacterial growth, posing a significant risk of infection if the product is injected.

Oral B12 Supplements: Less Strict, but Still Important

Unlike injections, most oral B12 supplements, such as capsules or standard tablets, do not require refrigeration and are considered shelf-stable. However, this does not mean they are invincible. The manufacturer’s instructions should always be followed, and a cool, dry place away from direct sunlight is the standard recommendation. Exposure to excessive heat and humidity over a long period can still degrade the vitamin, though usually at a slower rate than with injectable forms.

Comparison Table: Refrigerated vs. Shelf-Stable B12


Feature	Refrigerated B12 (e.g., injections, some liquids)	Shelf-Stable B12 (e.g., most tablets, capsules)
Storage Conditions	Requires consistent refrigeration (2-8°C).	Store in a cool, dry place away from direct sunlight.
Temperature Sensitivity	Highly sensitive to heat and temperature fluctuations.	Tolerant of standard room temperatures (around 20-25°C).
Potency Risk	Significant risk of degradation and loss of potency if not refrigerated.	Less risk of rapid degradation, but long-term heat exposure can reduce effectiveness.
Safety Risk	High risk of bacterial growth and potential injection-site infection if contaminated.	Generally low risk, but improper storage can lead to diminished quality and potential side effects.
Visual Signs of Spoilage	Cloudy appearance, change in color or thickness.	Less obvious signs; often requires checking expiry dates.

What to Do if You Forget to Refrigerate B12

If you have a B12 product that requires refrigeration and you've accidentally left it out, here are the steps to take:

Assess the Product Type: First, confirm if the product actually requires refrigeration by reading the label. Many people incorrectly refrigerate shelf-stable oral vitamins.
Check for Changes: If it's an injectable or liquid, inspect it for any changes in color, cloudiness, or odor. If any are present, the product is compromised and should be discarded.
Check Exposure Time: Consider how long the product was out of the fridge and at what temperature. Some B12 forms can tolerate brief exposure to room temperature, but prolonged heat can be damaging.
Consult a Professional: The safest action is to contact your pharmacist or doctor. They can provide specific guidance based on the brand, formulation, and duration of improper storage. It is always better to be safe and replace a potentially compromised product.

Conclusion: Always Follow Storage Directions

In conclusion, what happens if you don't refrigerate B12 depends entirely on the formulation. While most standard oral supplements are fine at room temperature, injectable and certain other forms require strict temperature control to remain safe and potent. Ignoring these instructions can lead to a less effective treatment or, in the case of injections, potential health risks from contamination. Always read and follow the storage directions provided by the manufacturer to ensure your B12 supplement provides the maximum health benefits it is designed for.

Visit the NIH Office of Dietary Supplements for more information on B12

Frequently Asked Questions

It depends on the type. If it is an oral tablet, it is likely fine, but check the label. If it is an injectable or specific liquid form that requires refrigeration, it may have lost potency or become unsafe.

Look for visible changes like cloudiness, a change in color, or a strange odor. If any of these are present, do not use it and dispose of it safely. When in doubt, throw it out.

No, most common oral tablets and capsules are shelf-stable. The need for refrigeration is specific to certain formulations, such as injections and some liquid or sublingual products.

Extended exposure to excessive heat and humidity can slowly degrade the potency of oral supplements. For best results, store them in a cool, dry place.

For B12 injections that require refrigeration, the recommended temperature is typically between 2°C and 8°C (36°F to 46°F).

The safest course of action is to contact your pharmacist or healthcare provider immediately. They can advise you on whether the product can still be used safely, but replacement is often recommended.

Heat exposure is more likely to cause B12 to lose its potency, rather than become toxic. The bigger risk for injectables is bacterial contamination in an un-refrigerated vial, which can lead to infection.