Are Probiotics Dead on Arrival? A Research Review

Are Probiotics Dead on Arrival? A Research Review

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More and more consumers worldwide are taking probiotics because of their proven health benefits. Clinical studies show that probiotics can support optimal gut health and may even improve mental health.

But because probiotics are living organisms, are they dead by the time they arrive to your house in the mail? Are any probiotic brands tested and proven to be alive at the point of delivery? Does taking whole food probiotics resolve this potential issue?

In this article we'll answer all of these questions and more, as we analyze clinical studies to give our take on whether probiotics are likely to be dead on arrival.

We'll compare the benefits of whole food probiotics to supplemental probiotics, and summarize the research on the health benefits of probiotic supplementation.

We'll also share a third-party testing resource that consumers can use to check if a probiotic brand has as many live probiotics as they claim after shipping.

Do Probiotics Survive Delivery?

Probiotics are living organisms. They’re typically measured in colony-forming units (CFU), and most probiotic supplements contain a CFU figure in the billions.

For probiotics to be optimally effective, they should be alive when consumed. We haven’t come across any clinical research suggesting that consuming dead probiotics is beneficial to human health.

But when purchasing a probiotic supplement online, it has to be shipped (from a warehouse it was likely at for months or years) and can be exposed to high temperatures which can cause probiotic death.

Even when purchasing a probiotic supplement off-the-shelf in a drugstore or grocery store, that product was still likely warehoused and delivered from elsewhere, which raises the concern of how long probiotics stay alive post-manufacturing.

Some probiotic supplements are shelf-stable, meaning they’re stored at room temperature. This may lead to increased rates of probiotic death, because many probiotic strains are sensitive to heat. 

A medical review on two of the most popular probiotic species, Lactobacillus acidophilus and Bifidobacterium spp., found that their health benefits are directly related to what percentage of probiotics survive the manufacturing and storage processes.

A medical review published in the Journal of Functional Foods found that heat levels over 45° Celsius were harmful to probiotic survival, and these temperatures are regularly achieved during supplement manufacturing.

Probiotics aren’t only exposed to stressful conditions during manufacturing, but also during storage, transit and due to degradation over time.

Some dietary supplement warehousing facilities aren’t adequately heat-controlled, and probiotics sitting in hot warehouses for months on end aren’t likely to be very effective.

Very few freighting companies have adequate temperature-monitoring technology in our experience, and this is another factor that can cause probiotic death.

So how can consumers ensure that the probiotic supplement they're considering will actually have live probiotics when it reaches their door? We'll explain in the next section.

How Third-Party Testing Helps

ConsumerLab third-party tested probiotic results

There are third-party testing companies that test off-the-shelf probiotics to see if they contain as many live probiotics as their label claims.

The testing company we trust the most is called ConsumerLab, because this company is run by scientists and publishes the full raw data from their tests of off-the-shelf supplements.

ConsumerLab has tested a wide variety of probiotics, and found some of them (like the Nature's Bounty probiotic shown in the screenshot above) to contain as many CFU of probiotics as advertised.

Are Whole Food Probiotics Better?

One core difference between getting probiotics from dietary supplements and from whole foods is that probiotics in supplements typically die over time, while probiotics in food are exposed to enzymes and other naturally-occurring compounds which actually encourage growth over time.

A medical review published in the Foods journal documents how the fermentation process encourages growth of health-promoting organisms.

Here are a few whole foods rich in probiotics:


Sauerkraut is one of the most popular probiotic foods because it’s cheap, easy to find, and versatile.

Because ‘kraut can be stored at room temperature, it tends to be significantly cheaper than other probiotic foods, and can be acquired in bulk at many grocery stores.

We generally recommend choosing sauerkraut with a label notice stating "contains live and active cultures," because pasteurized kraut (which is heat-treated) won't have the same probiotic benefits as raw kraut.


Kimchi is a fermented cabbage product similar to sauerkraut which is common in Asian cuisine. It tends to be more expensive than sauerkraut and also usually has other spices added.

A medical review, published in the Journal of Medicinal Food, describes how kimchi has clinically proven anticancer, antiobesity, anticonstipation and cholesterol reduction benefits.


Yogurt is one of the oldest and most popular probiotics. It tends to have fewer CFU than sauerkraut and kimchi, but can be more tolerable and more accessible.

Medical research shows that yogurt consumption is associated with a reduced risk of cardiovascular disease and obesity.

We recommend choosing a yogurt that's free of added sugar and sourced from grass-fed animals, as animal products from grass-fed animals are more nutritionally dense than products from conventionally-raised animals.


Pickles are another probiotic food that can benefit health. It’s important to select fermented pickles, as some brands sell pickles in vinegar which aren’t truly fermented and won’t have the same probiotic benefits.

A video published by TIME highlights ten foods that are naturally rich in probiotics:

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There are many factors that can negatively impact probiotics in supplemental form, such as heat, storage conditions, transit and time.

We recommend checking a third-party lab testing resource like ConsumerLab before purchasing supplemental probiotics, to make sure they contain as many CFU as stated on the label.

Otherwise, you may be paying for probiotics that are dead when they reach your door.

For consumers purchasing probiotics in stores, purchasing refrigerated probiotics may be a better bet than purchasing shelf-stable probiotics, because the refrigeration process preserves live cultures.

Fermented whole foods like yogurt and sauerkraut are naturally rich in probiotics, and the probiotic content generally increases over time, while the probiotic content in dietary supplements generally decreases over time.

Whole food probiotic sources also provide other nutritional benefits.