Prebiotics vs. probiotics: What’s the difference?


If you suffer from irritable bowel syndrome or general digestive troubles, both prebiotics and probiotics can be useful in managing your symptoms.

BestReviews is reader-supported and may earn an affiliate commission. Details.

Are prebiotics or probiotics best?

The microbiome in your digestive tract is home to trillions of bacteria, a healthy balance of which is important for a range of aspects of your health, including digestive health, heart health and brain health. You may have heard about probiotics and prebiotics being good for your digestive microbiome, but what’s the difference, and which should you take? 

Probiotics contain a range of beneficial bacteria that can seed in your gut, redressing an imbalance or increasing the diversity of strains living there, while prebiotics are essentially food for the good bacteria that already exist in your digestive tract, which boosts their numbers. 


Prebiotics act as food for the bacteria in your digestive system. Prebiotic supplements generally contain plant-based fibers, such as inulin from green bananas or Jerusalem artichokes. These fibers are indigestible, but the beneficial bacteria in your intestines eat them. With more food to eat, good bacteria multiply, increasing the overall health of your gut.

You can expect to pay anywhere from around $5 for a basic prebiotic supplement to more than $25 for an advanced formula. If you want more details, head to BestReviews for the full guide to prebiotic supplements.

Prebiotics pros

  • Some prebiotic supplements contain added herbs, vitamins and minerals for an all-around boost to your health.
  • You can buy probiotic powders that you can mix with other foods to make them more palatable. So, if you don’t like swallowing capsules, you can simply add a scoop of prebiotics to your smoothie or sprinkle in on cereal.
  • On average, prebiotics cost less than probiotics, so they’re a great choice for buyers on a budget.

Prebiotics cons

  • Prebiotics can only feed the existing strains of bacteria in your digestive tract; they can’t seed new strains.
  • If you eat a varied diet, you probably already get enough prebiotic foods to fuel your good gut bacteria. Popular prebiotic foods include apples (with the skin on), peas, beans, oats, onions and garlic.

Best prebiotics 

Swanson Prebiotic Capsules

Swanson Prebiotic Capsules

These affordable prebiotics come in veggie capsules and give you enough capsules to last one person 60 days. In just four weeks, they could increase your good gut flora by up to 500%. 

Bio Schwartz Prebiotics for Advanced Gut Health

Bio Schwartz Prebiotics for Advanced Gut Health

This advanced prebiotic formula is specially designed so it feeds only the good bacteria in your intestines. It’s free from common allergens, plus it’s well-tolerated and doesn’t cause excess gas or other gastrointestinal symptoms.

Hyperbiotics Organic Prebiotic Powder

Hyperbiotics Organic Prebiotic Powder

With a powdered formula rather than capsules, this prebiotic makes it easy to adjust your dose. What’s more, it’s U.S. Department of Agriculture-certified organic, which is perfect for anyone who prefers to stick to organic foods.


Probiotics contain live bacteria of the beneficial kind. By taking them, you can seed your gut microbiome with more good bacteria or even new strains that you might lack. You can buy different probiotic formulas for different purposes — depending on the strains they contain — such as for improved immunity, digestive health or respiratory health. However, you’ll also find general probiotics without one specific purpose, which are good for general gut health and overall well-being. 

All probiotics contain a different number of bacterial strains and of individual bacteria, known as colony forming units. Although you can find some probiotics from around $15, advanced options can cost as much as $50. For more information, check out the probiotics buying guide at BestReviews.

Probiotics pros

  • Because they contain live bacteria that can seed in your digestive tract, probiotics are extremely effective at increasing levels of good bacteria and may even introduce new strains of beneficial bacteria.
  • Probiotics are especially useful after taking a course of antibiotics, which are known to kill off some gut flora and can cause an imbalance in the microbiome of your digestive tract.
  • Some probiotics also contain prebiotic ingredients, which provides food for the good bacteria in the probiotics, making them even more effective. 
  • You can find probiotics in a range of formulations, including liquids and gummies, which is great if you don’t like swallowing capsules.

Probiotics cons

  • Some probiotics require refrigeration to keep the bacteria alive, which can be inconvenient. 
  • If you don’t eat a range of prebiotic foods or take a prebiotic supplement, the bacteria in probiotics may not have enough food to multiply. 

Best probiotics 

NATURELO Probiotic Supplement

NATURELO Probiotic Supplement

With 50 billion CFUs from 11 strains, this probiotic supplement contains plenty of good bacteria and the delayed-release formula ensures that it isn’t killed off by stomach acid and digestive enzymes before it reaches your intestines. This supplement comes in vegetable capsules and is free from major allergens, like soy and dairy.

Mary Ruth's Liquid Probiotic 

Mary Ruth’s Liquid Probiotic 

This USDA-certified organic probiotic comes in liquid form, which is perfect for anyone who doesn’t want to take capsules. It contains 12 live strains, all of which are extracted from organic grasses. 

Terranics Probiotics

Terranics Probiotics

This probiotic supplement covers all your bases with 60 billion CFUs from 19 strains of good bacteria, plus added prebiotics to feed them. It has delayed-release technology so that the good bacteria aren’t killed by stomach acid, and is shelf-stable so there’s no need to keep it refrigerated. 

Should you get prebiotics or probiotics?

Now that you know the difference between prebiotics and probiotics, you might have a better idea about which option is right for you. If you’re looking to feed the existing good bacteria in your digestive tract, then a prebiotic will suffice, but if you want to boost the diversity of your gut flora and address any serious imbalances, then probiotics are right for you. Probiotics are particularly useful after taking a cause of antibiotics or taking other medication or undergoing procedures that may have affected your gut microbiome. 

Ultimately, prebiotics are like food for probiotics, so for the best results, you should take a probiotic with added prebiotic ingredients, or you should take both a prebiotic and probiotic at the same time. 


Sign up here to receive the BestReviews weekly newsletter for useful advice on new products and noteworthy deals.

Lauren Corona writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

Copyright 2021 BestReviews, a Nexstar company. All rights reserved.