Most won’t… but a few can.
With record-breaking temperatures all across the country, a lot of people are wondering how that affects their probiotics.
Whether you buy them locally but have to leave them in the car… or they get delivered and left in your mailbox or on the porch… your probiotics have probably been exposed to extremely high temperatures. That can be fatal for them, making them useless to you.
Most probiotics, that is.
Because there are some probiotics that can survive intense heat and remain completely intact and viable.
Those are probiotics you can count on no matter what’s going on in the forecast. And those are the probiotics you want.
What Happens to Probiotics in the Heat?
Like all living things, probiotic bacteria can be sensitive to heat, humidity, and other uncomfortable conditions.[1]
Most probiotics are especially heat-sensitive and can’t tolerate high temperatures. Popular probiotic strains such as Lactobacillus acidophilus and Bifidobacterium bifidum begin to lose stability and potency at around 72°F.[2]
That means during shipping, storage, and while sitting in mailboxes or cars those probiotics can begin to die off.[3] Even if they do survive, heat exposure can cause:
- breakdown of cellular structures
- lost viability
- impaired metabolic activity
- lost ability to produce short chain fatty acids and other beneficial compounds
And when you really think about that, you may start to wonder: If my probiotics can’t survive warm weather, how will they survive my body temperature?
Truthfully, most don’t.
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The Refrigeration Myth
You grab a bottle of probiotics from the refrigerated case at the store. Or maybe your probiotics get delivered surrounded by ice packs. And as soon as you can, you put the bottle in the fridge just like the label says to do.
But what about all the other steps along the way? Cold storage isn’t guaranteed along every step in the chain. “Keep refrigerated” doesn’t mean that your probiotics were kept cool and comfortable the whole way from the manufacturer to your house.
They sit in warehouses. They sit in trucks. They sit in storerooms. Maybe all of those places were refrigerated or air conditioned…
But maybe they weren’t. There’s no way to know.
So there’s no way to know that the probiotics in the bottle are still viable and beneficial. Meaning they probably won’t work for you the way you want them to.
What About Shelf-Stable Probiotics?
Shelf-stable probiotics don’t require refrigeration to survive. They’re usually created with freeze-dried strains that can then easily live at room temperature.
The freeze-drying process dehydrates the probiotics at very low temperatures and puts them into a sort of dormant state. They’re supposed to reactivate when they’re rehydrated in the body.
Sounds good… but it doesn’t always work that way.
Many probiotic bacteria die during the drying stage of this process. The freezing rate can also kill off probiotics. And unless the capsule they’re in is specially coated to survive stomach acid, the probiotics won’t.[4]
The probiotics that do survive are shelf-stable at room temperature. That means they can live longer without being refrigerated. It doesn’t mean they can tolerate extremely high heats. Like being left out on a sunny porch on a 95° day.
How Much Does the CFU Matter?
Probiotic supplement labels include their CFU (colony forming units) count, with those counts usually in the billions.
But what they don’t specify is whether the CFU reflects the count at the time of manufacturing or the time when the product is set to expire.
Most often, it’s the manufacturing count. The number of active, live probiotics when they hit the bottle. Not after they’ve been stored, shipped, and stored again in uncontrolled environments. So the CFU on the label could be billions off from what’s actually in the bottle by the time you get it.
Manufacturers know that probiotics are vulnerable. So it’s common practice to overpack the CFU count knowing that a lot of the bacteria will die. The more CFU they start with, the better chance that at least some of them will get to you alive.
And after heat exposure? You really have no idea how many live, active probiotics you’re getting in any particular capsule. You’re left with guesswork, not knowing if any probiotics survived the heat. And probiotics only work if they arrive alive and become active in your gut microbiome.
Survivor: Probiotics Edition
When it comes to probiotics, you want strains that are proven survivors.
Spore probiotics are designed by nature to survive practically anything. They have protective shells that allow them to withstand even the harshest conditions. Extreme heat—hotter than boiling. Sub-zero temperatures, even permafrost. Acidic environments, like your stomach.
Those shells keep the probiotics in stasis so they can survive until the danger has passed. Then, when they reach a favorable environment (your gut), the spore shells dissolve, allowing the probiotics to awaken and flourish. That advantage makes spore probiotics stronger and more resilient that other types of probiotic bacteria.[5]
Unlike refrigerated and shelf-stable probiotics, spore probiotics shake off the hottest days of summer. They can sit on the porch or in the mailbox when it’s 100° without breaking a sweat.[6] That’s nothing for these intrepid probiotic bacteria. Research shows that:
- Bacillus subtilis HU58 spore probiotics can survive baking temperatures of 455°[7]
- Bacillus spores including Bacillus coagulans can withstand prolonged baking times, making them a viable addition to baked goods.[8]
- Bacillus clausii spore probiotics use heat shock proteins to handle stress conditions and resist damage from heat[9]
And they always survive the digestive process, even though that’s a deadly trip for most probiotics. Spore probiotics don’t die from body heat. They skate through stomach acid and bile salts. And their armor carries them safely to the gut microbiome.[10]
As soon as spore probiotics arrive in your gut, their protective shells dissolve and the probiotic bacteria reactivate. They immediately begin to clear out their homes and have a special talent for encouraging native probiotic bacteria in the gut to establish colonies. They create an inviting space for a diverse population of beneficial bacteria to grow and flourish, keeping the gut microbiome in healthy balance.
Exactly what you want and expect from your probiotic. In every single capsule.
Support your best gut health. Try Just Thrive Probiotic today!
Just Thrive Probiotic (30/90)
The only probiotic guaranteed to arrive 100% alive
Beat the Heat with Spore Probiotics from Just Thrive
Spore-based probiotics have a built-in advantage that other forms of probiotics don’t, no matter what it says on their labels.
The protective armor that shields spore probiotics ensures they can survive heat and other harsh conditions. They arrive in your gut microbiome alive and ready to support a healthy gut microbiome. So you don’t have to wonder if your probiotics survived summer heat or freezing winters.
Just Thrive Probiotic contains four clinically studied spore probiotics:
- Bacillus indicus HU36™
- Bacillus subtilis HU58™
- Bacillus coagulans (SC-208)
- Bacillus clausii (SC-109)
This specific combination of spore probiotics is proven to support diversity and balance in the gut microbiome.
>> Trust Just Thrive Probiotic for 100% survivability in any weather, every time.
But if you’re not quite sure about trying Just Thrive Probiotic, we can help with that.
EVERY Just Thrive purchase is covered by our Bottom of the Bottle, 100% money back guarantee.
That means you can try Just Thrive Probiotic to see how well it works for you… and we’re betting that you’ll notice a positive difference.
But if for any reason you don’t feel it has helped you, you can ask for a full product refund at any time. Even if it’s 3 months or 3 years later. Even if the bottle is empty.
Sources
- Aguinaga Bósquez JP, Oǧuz E, Cebeci A, Majadi M, Kiskó G, Gillay Z, Kovacs Z. Characterization and Viability Prediction of Commercial Probiotic Supplements under Temperature and Concentration Conditioning
- Rerksuppaphol S, Rerksuppaphol L. Lactobacillus acidophilus and Bifidobacterium bifidum stored at ambient temperature are effective in the treatment of acute diarrhoea. Ann Trop Paediatr. 2010;30(4):299-304.
- Wendel U. Assessing Viability and Stress Tolerance of Probiotics-A Review. Front Microbiol. 2022 Jan 27;12:818468.
- Fredua-Agyeman M. Surviving process and transit: Controlled freeze drying, storage and enteric coated capsules for targeted delivery of probiotic Lactobacillusacidophilus. Heliyon. 2024 Mar 20;10(7):e28407.
- Elshaghabee FMF, Rokana N, Gulhane RD, Sharma C, Panwar H. Bacillus As Potential Probiotics: Status, Concerns, and Future Perspectives. Front Microbiol. 2017 Aug 10;8:1490.
- Soares M, et al., Review - Sporeforming probiotic bacteria: Characteristics, health benefits, and technological aspects for their applications in foods and beverages. Trends in Food Science & Technology. Volume 138, August 2023, Pages 453-469.
- Permpoonpattana P, Hong HA, Khaneja R, Cutting SM. Evaluation of Bacillus subtilis strains as probiotics and their potential as a food ingredient. Benef Microbes. 2012 Jun 1;3(2):127-35.
- Payne J. Determining the viability and stability of Bacillus in baked products. LWT. Volume 218, 15 February 2025, 117519
- Khatri I, Sharma G, Subramanian S. Composite genome sequence of Bacillus clausii, a probiotic commercially available as Enterogermina®, and insights into its probiotic properties. BMC Microbiol. 2019 Dec 30;19(1):307.
- Payne J, Bellmer D, Jadeja R, Muriana P. The Potential of Bacillus Species as Probiotics in the Food Industry: A Review. Foods. 2024 Aug 2;13(15):2444.