Do probiotics need to be refrigerated?

Written by: Kari Raman, PharmD, RPh
Published June 25, 2023

When it comes to probiotics, a common question I receive in the pharmacy is: “Do probiotics need to be refrigerated?” In fact, I get this question often enough that it’s time that I write an article about it. 

I understand where the confusion comes from – some packages clearly state that refrigeration is required, while others say nothing. But when you buy them, they are usually just sitting on the pharmacy shelf, not being kept cold. And, it’s pretty obvious that many probiotic-containing foods like yogurts need to be kept in the fridge. 

The truth is a bit more nuanced and depends on a variety of factors including the specific strain, formulation, and manufacturer’s recommendation. 

Understanding Probiotic Stability

One of the critical factors that determine if a probiotic needs to be refrigerated is its stability. Probiotics, being live organisms, have to stay alive in order to exert their beneficial effects on the body. They need to survive not just in the bottle, but also the harsh conditions of the stomach and the upper part of the small intestine. 

Side note – they are alive!

Yup, probiotics are alive. It’s a fascinating concept, isn’t it, and not every patient that comes into the pharmacy understands this. These microscopic organisms, often referred to as “good bacteria,” are alive and teeming with potential benefits for our bodies – note that they can be other types of organisms than just bacteria; learn more in my species article. 

Found in a variety of foods like yogurt, sauerkraut, and certain types of cheese, as well as in supplement form, probiotics are live bacteria and yeasts that may be able to contribute positively to our health, especially our digestive system. They work by helping maintain a balance of “good” and “bad” bacteria in our bodies. This balance is vital for keeping our gut healthy, supporting our immune system, and even influencing our mood and mental health. As living entities, probiotics need certain conditions to survive, which is why questions about their storage and care, such as the need for refrigeration, often arise. It’s vital to remember that keeping them alive is key to reaping their potential health benefits.

The stability of a probiotic can be affected by several factors, such as heat, light, moisture, and oxygen exposure. Too much of any of these can potentially kill the bacteria, thereby reducing their efficacy. This is why some products are recommended to be stored in the refrigerator, as it helps maintain a stable environment that supports their survival. 

Do All Probiotics Need to be Refrigerated?

Not all probiotics require refrigeration. Many are freeze-dried during production to keep them dormant and stable, meaning they can be kept at room temperature. However, once the bottle is opened, the contents are exposed to environmental factors such as heat, light, moisture, and oxygen that were previously sealed out. These elements can threaten the survival and effectiveness of the live cultures. Refrigeration after opening helps to create a more stable and cool environment, reducing the impact of these factors and helping to extend the life and potency of the probiotics. Before opening, the product is sealed and often packaged to prevent exposure to these potentially damaging factors, allowing for room temperature storage. So that explains the mystery of how they can be on the shelf at the pharmacy but need to go into the fridge at home once opened. 

How the probiotic is formulated plays a large role in its stability. For example, some are encapsulated in a way that protects them from heat and moisture, enabling them to be stored at room temperature. 

On the other hand, there are probiotics, often found in liquid or fresh food products like yogurts and drinks, that do require refrigeration. These products typically have a shorter shelf life and need to be kept cool to keep them alive. And you probably need to keep that yogurt in the fridge, but you already knew that!

Bacteria phases of life

One item that impacts if the supplement needs to be refrigerated is the phase of life that the bacteria are packaged in. The life cycle stages of bacteria can influence their storage needs, including whether they need to be refrigerated. When bacteria are actively growing and dividing, they’re in what’s called the “log phase” of their life cycle, and they tend to be very sensitive to environmental conditions. 

Many probiotic bacteria are packaged in what is called the “lag phase,” which helps them survive the manufacturing process and shelf life. However, once these bacteria are exposed to favorable conditions (like the warm, moist environment of your gut), they can exit the spore phase, become active, and start dividing again. 

Refrigerating probiotics can help keep the bacteria in a less active phase, preserving their lifespan and efficacy until they reach your gut. By slowing metabolic activity, it prevents the bacteria from using up their energy stores and dying off.

The Manufacturer’s Recommendation is Key

The best way to know if your probiotic needs to be refrigerated is to check the product label or packaging. The manufacturer’s storage instructions will provide the necessary guidance. If refrigeration is recommended, it’s best to keep the product in the fridge. If it says ‘refrigerate after opening,’ it means the product can be stored at room temperature until it’s opened.

I have seen more and more probiotics in special fridge end caps at expensive supermarkets. These (most likely) need to be kept cold at all times – again, check the package. 

Should you put them into the fridge if the package doesn’t say so?

This is a lot harder of a question. It seems unlikely that refrigeration will damage most of these supplements, but it’s possible that some yeasts won’t love the fridge. If you have serious questions, call the manufacturer and ask! 

Impact of Refrigeration on Probiotic Potency

Refrigeration can help extend the shelf life of probiotics and maintain their potency, especially for certain strains that are more susceptible to heat and moisture. However, not all probiotics will lose their effectiveness if not refrigerated. Advances in technology have made it possible for many to remain stable at room temperature – if your package doesn’t say that they need to go into the fridge, you are probably Ok leaving them out. 

Can you store probiotics in the car?

No… storing probiotics in the car is generally not advisable. Cars can experience significant temperature fluctuations, especially on hot days or in direct sunlight, which can result in heat levels that could damage or kill the live bacteria. Additionally, cars can also become very cold in winter months, which may also adversely affect the supplement. Moisture is another concern, as condensation could potentially seep into the product. Remember, probiotics are live organisms that require certain conditions to survive and remain effective. It’s best to store them as recommended by the manufacturer, typically in a cool, dry place away from direct light, or in the refrigerator if specified. A car doesn’t provide the stable environment that they need to maintain their potency and efficacy.

It’s not just temperature

One last thing I want to remind everyone is that the potency of a probiotic is not just about whether or not it is refrigerated, but also about the count of colony forming units (CFUs) it provides, the specific strains it contains, and whether these strains are suited to your specific health needs.

So, while the question, “Do probiotics need to be refrigerated?” is a valid one, it’s not the only consideration when it comes to choosing a probiotic. Consider talking with a healthcare provider to ensure you’re choosing the right probiotic for your needs.

Overall, whether a probiotic needs to be refrigerated depends on the product’s specific formulation and the manufacturer’s recommendation. Read the package! Or ask your pharmacist, who will probably … read the package.

What are Probiotics?

Sometimes at the pharmacy I think it’s helpful to explain what probiotics are when I remind patients that they need to be refrigerated after opening. So let’s talk about what they are.

Probiotics are live microorganisms, often referred to as “good bacteria,” that when consumed in adequate amounts may provide health benefits to the host, usually humans. They are found in many foods and supplements and are intended to assist the body’s naturally occurring gut microbiota. Some can also be yeasts, which may also need to be kept in the fridge.

How do they work?

The human body, especially the gut, is home to trillions of bacteria and other things like yeasts – a mixture of both beneficial and harmful species. It’s called the microbiome. Sometimes, due to factors like antibiotics, stress, or poor diet, the balance between the good and bad bacteria can be disrupted. Probiotics supplements or even some foods may help restore this balance by introducing beneficial bacteria into the body.

Possible Benefits

Probiotics might aid in several health areas. 

Probiotics may help in treating conditions like diarrhea, especially when caused by antibiotics. In that case, the ones you are most likely to see in the pharmacy are Florastor and Culturelle, although there are others that you should consider as well. They might also help in managing symptoms of irritable bowel syndrome (IBS). Some research suggests that probiotics could boost the immune system by promoting the production of natural antibodies in the body. There is a growing body of evidence linking gut health to mood and mental health. Some studies suggest that taking probiotics might help reduce symptoms of depression and anxiety. Certain probiotics might help lower LDL (bad) cholesterol and blood pressure, benefiting heart health. Some strains of probiotics may prevent the absorption of dietary fat in the intestine, which could aid in weight loss. 

So those are a lot of possible benefits, although research is still emerging – and also, again, results will really vary by person and situation. Not everyone will get a benefit from supplementation. If you are having a health condition, like recurring upset stomach or even something worse, you should always see your primary care physician before beginning a supplementation program.


Pharmacist Kari Raman

I’m Kari Raman PharmD, RPh, and I am a licensed, practicing pharmacist. I hold a Doctorate in Pharmacy from The University of the Pacific, and I’ve served patients in retail, compounding and hospital pharmacies.

Probiotics are confusing!

One of the most common questions I get asked by patients is about probiotics. And the truth is, probiotics are not as well understood by the healthcare community as they should be.

So I’ve been reading a lot of probiotic clinical trials, and sharing what I’m learning here.

I hope Pharmacist Probiotics helps you find out if there is a type of probiotic that works for you!