Before You Buy Another Probiotic: How to Choose the One You Actually Need
How to Choose the Right Probiotic
More strains and more billions aren't automatically better. The right probiotic depends on what you're trying to accomplish.
Walk into almost any supplement aisle and probiotics can become confusing very quickly.
Ten billion. Thirty billion. A hundred billion CFUs. One strain, five strains, eight strains. Lactobacillus, Bifidobacterium, Saccharomyces. Refrigerated. Shelf stable. Women's formulas. Daily formulas. Digestive formulas.
It is easy to look at all those numbers and assume that the bottle with the most billions and the longest list of organisms must be the best one.
It doesn't work that way.
I've worked in preventive and functional medicine for years, and when someone asks me which probiotic to take, my first question isn't about the brand.
It's why do you want to take a probiotic?
That question can narrow the choices considerably.
First, what is a probiotic?
Probiotics are live microorganisms that, when taken in appropriate amounts, may provide a health benefit. Many are bacteria similar to microorganisms already living in the digestive tract, although some probiotics are beneficial yeasts.
The important thing to understand is that "probiotic" describes an enormous category.
Different microorganisms can behave differently in the body. Even two probiotics belonging to the same species aren't necessarily interchangeable.
That's why a good probiotic label tells you more than Lactobacillus or Bifidobacterium. Ideally, you want to know the genus, species and strain.
Think of it a little like a family name. Knowing that someone is a Smith doesn't tell you which Smith you're talking about. With probiotics, those additional letters and numbers after the species name can matter because research may have been performed on that particular strain.
Don't choose a probiotic by the biggest number
CFU stands for colony-forming units, an estimate of the number of viable microorganisms in a probiotic.
It is useful information, but it has become an easy marketing tool.
If one bottle contains 15 billion CFUs and another contains 100 billion, it is tempting to assume that 100 billion must be better.
The National Institutes of Health specifically cautions against that assumption. Higher CFU counts do not necessarily mean greater health benefits. What matters is the particular microorganism, the amount studied and what you're trying to accomplish.
The same goes for the number of strains.
A probiotic containing eight strains isn't automatically better than one containing two. A simpler product containing well-studied strains may be exactly what someone needs.
More isn't the goal. Appropriate is the goal.
So how do I choose?
I start with the reason someone is considering a probiotic.
Are you generally healthy and simply interested in supporting digestive health?
Are you dealing with occasional bloating or changes in bowel habits?
Have you recently taken antibiotics?
Are you traveling?
Are you looking for something specifically formulated for women's health?
Are you dealing with persistent digestive symptoms that really should be evaluated rather than repeatedly trying supplements?
Those are very different situations.
One reason I use professional supplement lines is that they make it possible to choose among formulas rather than treating every person as though they need the same generic product. Metagenics is one of the professional lines available through my practitioner storefront, and its UltraFlora line is a useful example of how different probiotic formulations can serve different purposes.
If you're looking for basic daily support
UltraFlora Balance is one of the simpler places to begin looking.
It contains two researched strains, Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07, with 15 billion CFUs per serving.
For someone looking for straightforward daily digestive and immune support rather than trying to address a particular problem, I like the logic of starting simple.
There isn't a prize for taking the most complicated probiotic.
If you want broader strain diversity
UltraFlora Complete takes a different approach, combining multiple strains rather than relying on two.
This may appeal to someone looking for broader microbiome support, but here's where I want to make an important distinction: the value isn't simply that there are more strains.
A multistrain product should be chosen because its formulation makes sense for what you want from it, not because eight or nine names on a label look more impressive than two.
Research comparing single- and multistrain probiotics has not established that piling more strains into a capsule automatically makes a probiotic more effective.
What if bloating and abdominal discomfort are the reason you're shopping?
This is where people often start buying probiotics almost randomly.
They have bloating, gas, abdominal discomfort, irregularity or urgency, so they decide their "gut must be off" and reach for the highest-potency probiotic they can find.
That's not necessarily the best approach.
Metagenics offers UltraFlora IB, a higher-potency formulation using NCFM and Bi-07 that is designed around intestinal comfort, including occasional bloating and abdominal discomfort.
But persistent bloating isn't a diagnosis.
There are many possible reasons for abdominal symptoms, and continually adding supplements without understanding what is causing them can delay figuring out what is actually going on.
If symptoms are persistent, worsening, severe, associated with bleeding, unexplained weight loss, fever or other concerning changes, that's a conversation for your health care provider—not another trip down the supplement aisle.
After antibiotics is a different question
Antibiotics can disrupt the intestinal microbial community along with killing the bacteria they were prescribed to treat. That is one reason people frequently ask about probiotics during or after a course of antibiotics.
There is research suggesting that certain probiotics may reduce the risk of antibiotic-associated diarrhea, but this is another area where the strain matters. We can't take evidence about one particular probiotic and automatically apply it to every bottle labeled "probiotic."
Some formulations also include Saccharomyces boulardii, which is a beneficial yeast rather than a bacterium and has been studied in gastrointestinal health.
Metagenics UltraFlora Spectrum, for example, combines several bacterial strains with S. boulardii. That makes it fundamentally different from a simple two-strain daily probiotic.
If you're taking antibiotics, particularly if you have other medical conditions or take multiple medications, talk with your health care professional about whether a probiotic is appropriate and how to time it.
Women's probiotics demonstrate why the strain matters
Women's probiotic formulas provide one of the clearest examples of why I don't recommend choosing according to CFUs alone.
Metagenics' women's formulations include specific strains such as Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 that have been studied in relation to vaginal microflora.
That's a completely different goal from choosing a general digestive probiotic.
The important question isn't, "Which bottle has the most bacteria?"
It is, "Does this formula contain organisms that have actually been studied for the reason I'm taking it?"
That's a much better way to shop.
What about the 100-billion-plus probiotics?
There are high-potency formulations, including Metagenics BiomePro, with CFU counts exceeding 100 billion.
There can be reasons for using a high-potency formulation. But I wouldn't choose one simply because the number looks impressive.
If 15 billion CFUs of appropriate, researched strains are suitable for what you're trying to accomplish, taking seven times that amount doesn't automatically make the product seven times better.
This is one of the biggest mistakes I see in supplement shopping generally: we confuse dosage with quality.
We do it with vitamins. We do it with magnesium. And we certainly do it with probiotics.
Your diet still matters
I don't want probiotics to become another way we try to put health into a capsule while ignoring food.
Your intestinal microbiome responds to what you eat.
Fiber-rich vegetables, fruits, legumes, whole grains, nuts and seeds provide substrates that beneficial organisms can use. Fermented foods can also contain live microorganisms, although not every fermented food contains probiotic strains with demonstrated health benefits.
This also brings us to prebiotics, which aren't the same thing as probiotics.
Probiotics are microorganisms. Prebiotics are substances—often particular types of fiber—that can be used by microorganisms already living in the gut.
Sometimes the question isn't simply, Which bacteria should I swallow?
It may also be, What am I feeding the microbial community I already have?
I'll come back to that in another article because prebiotics deserve their own discussion.
Not everyone should simply start taking probiotics
For most healthy people, probiotics generally have a good safety record, but "natural" doesn't mean universally appropriate.
People who are seriously ill, severely immunocompromised or otherwise medically vulnerable should discuss probiotic use with their health care team. Probiotics also shouldn't be used as a substitute for evaluating persistent gastrointestinal symptoms or treating a diagnosed condition.
And if a probiotic makes you feel substantially worse, don't assume that's proof that it's "working" or that you need to push through it.
Stop and reconsider why you're taking it.
Before you buy another probiotic
Turn the bottle around.
Don't start with the giant number on the front.
Look at the genus, species and strain. Look at the CFUs. Look at whether the manufacturer guarantees those CFUs through expiration rather than simply reporting what was present when the product was manufactured. Check the storage instructions.
Most importantly, ask what evidence exists for that particular formulation and the reason you want to take it.
That is a much better standard than buying whichever bottle promises the most billions.
If you're interested in the Metagenics probiotic formulations I've discussed here, you can explore them through my professional Metagenics practitioner storefront:
You don't need every probiotic on the shelf.
You need to understand what you're choosing—and why.
Sources
National Institutes of Health, Office of Dietary Supplements — Probiotics: Fact Sheet for Consumers
National Institutes of Health, Office of Dietary Supplements — Probiotics: Health Professional Fact Sheet
National Center for Complementary and Integrative Health — Probiotics: Usefulness and Safety
McFarland LV, Evans CT, Goldstein EJC — Strain-Specificity and Disease-Specificity of Probiotic Efficacy: A Systematic Review and Meta-Analysis
McFarland LV — Efficacy of Single-Strain Probiotics Versus Multi-Strain Mixtures: Systematic Review of Strain and Disease Specificity
Metagenics — UltraFlora and BiomePro probiotic product information and clinical research materials
This article is for educational purposes and is not intended to diagnose, treat or replace individualized medical care.