Do Probiotics Actually Work For Everyone? Here's What Experts Have To Say

Unless you've been living completely off the grid, you've likely heard a lot about probiotics by now. But do they actually work? And if so, how long does it take to see results? We dove into the research and picked the brains of a couple of gut health M.D.s to answer these burning probiotic questions and more.

Think of probiotics like little helpers in your digestive tract that work to maintain harmony in your gut ecosystem,* says Vincent Pedre, M.D., a board-certified internist and gut health expert. Adequate numbers of good bugs in the gut, "outnumber and antagonize unwelcome pathogens, including unfavorable bacteria, yeast, and parasites."

In other words, probiotics—which are live bacteria and yeasts—are fighting for you, helping to restore and maintain balance in your gut.* When you're getting poor sleep, are overly stressed, or are living off processed foods (to name a few things), these challenges can knock your gut out of balance.

Probiotics are the good bacteria that enter your gut, providing nourishing strains of bacteria to elevate your gut microbiome and combat microbial imbalance.*

But how does that happen, exactly? Probiotics essentially push out the unwanted gut residents.* The good bacteria invade their space and steal their food and nutrients2, creating an environment where the undesirable organisms can't survive. Eventually, those guys die off while the probiotics thrive and grow in numbers. 

As probiotics feed on fibers, they also produce beneficial byproducts called short-chain fatty acids (SCFAs). SCFAs fuel your intestinal cells and help strengthen your gut barrier3, two things that can improve your overall gut health and help strengthen it for future threats.* Will Bulsiewicz, M.D., MSCI, a gastroenterologist and internationally recognized gut health expert, calls SCFAs a "real game-changer" and says that their production can literally transform your gut—and overall—health.*

According to Shah, some people can see some positive results in 24 to 48 hours.* For others, it can take weeks or months to start seeing any changes.* It also depends on what you're trying to achieve with probiotics. 

Because of this, many people give up taking probiotics too soon, but those who stay consistent may be rewarded with better gut health and a more regularly functioning digestive system, among other potential health benefits like improved mood4, a better physiological response to stressors5, and a healthier immune system6.*

Your initial response to probiotics depends on your baseline gut health and how your body processes them.* Amy Shah, M.D., a double board-certified integrative doctor, explains that because probiotics are live organisms, everyone metabolizes them differently. 

You might start to feel gut health benefits within a day or two, or you might not for a while.* We are unique individuals, and so our responses to targeted supplements differ.

On the opposite end of the spectrum, you might experience some unwelcome side effects, like more gas and/or bloating—signs of detoxification die-off process called a Herxhemier (or Herx) reaction. The more imbalanced your gut is to start, the more uncomfortable this transition can be.

Shah says that this unpleasant phenomenon should start to go away after the first week or two as your body gets used to the new routine and your gut microbiome starts to return to balance.* If they don't, it could be a sign that you're dealing with some more chronic GI issues, like small intestine bacterial overgrowth (SIBO) or irritable bowel syndrome (IBS), which would require more targeted support from a trained physician.

There are several things that go into choosing the right probiotic. You want to make sure it's a high-quality supplement that actually contains enough viable—or living—bacteria to make a difference in your gut health.* The amount of each probiotic strain included should be based on clinical research evidence.

As a rule of thumb, Pedre recommends selecting a probiotic that has 5 to 100 billion colony-forming units (CFUs) and multiple strains that are targeted to your specific health needs.* He also says that your probiotic should undergo quality testing to make sure the claims on the bottle actually match what you get.

While refrigerated probiotics used to be the gold standard, there are a lot of high-quality, shelf-stable options out there now, so that's no longer an important deciding factor.

Probiotics are a wonderful supplement innovation. While some people see results in as little as 24 to 48 hours, for others, it can often take four weeks to three months to experience sustained benefits.*

If you want to see if probiotics can work for you, it's important to choose a high-quality supplement with multiple, science-backed living probiotic strains and stay consistent with taking it. And make sure you're prepared: Sometimes things can get a little worse before they get better. Of course, it's always a good idea to talk with your own doctor before taking any new supplements, including probiotics.