Exactly What Happens To Your Body When You Start Taking A Probiotic? Experts Weigh In

Sure, you may have heard that probiotics can have a positive influence on gut health—but, have you ever questioned why? What are the gut-friendly bugs so many people talk about, and what exactly happens to the body when they're added to a supplement routine?

Probiotics are a live bacteria that help support gut health.* When you take a probiotic supplement, you contribute more good bugs to your gut.* "The probiotics are like good cops," Robert Rountree, M.D., renowned integrative physician, previously told mbg. "We're putting in the good cops, and the good cops can keep watch over the bad guys."

By introducing good bacteria to the gut microbiome, probiotic supplements and foods can help support gut microbial balance and promote healthy digestion.* 

Since they are literally alive, functional medicine doctor Amy Shah, M.D., says probiotics will metabolize differently for different people. Depending on a person's existing gut health, they may take longer to start working or lead to side effects initially. 

For some people, probiotics can start to work within 24 to 48 hours, Shah says, while others may not experience results for weeks. Significant, positive changes in the gut microbiome could even take months to settle in.

The physical changes may vary from person to person, but if a probiotic is working properly, the gut health support should be noticeable and felt. 

According to Gandhi, an effective probiotic can help ease bloating and gas and promote abdominal comfort.* "For some it may translate to less fatigue, less brain fog, more energy, and being able to eat foods they could not tolerate before," she adds.* 

Before seeing improvements, some people may experience gastrointestinal side effects. "Many people can get gas or bloating in the first week or two since it's new bacteria for your ecosystem," Shah explains.  

Eventually, these effects should dissipate. If they don't, stop taking probiotics and consult a gastroenterologist or primary care physician for next steps. 

External effects, including environment, diet, prescriptions, and more, can change the microbiome daily. "But when you stop taking probiotics for at least three days, your microbiome changes drastically," Gandhi says.