First, everyone wanted probiotics. Then prebiotics. Now postbiotics are showing up on supplement labels. Here is what each one does, and why Bio Complete 3 includes all three.
Walk down any supplement aisle, and you can read the recent history of gut health on the labels. First came the probiotic supplement, packed with live bacteria. Then came the prebiotic supplement, made from the fiber those bacteria feed on. The newest arrival is the postbiotic supplement, and it asks a simple question. If what we really want is the good stuff gut bacteria produce, why not supply some of it directly? Gundry MD Bio Complete 3 was built around that idea, and it combines all three in one daily formula.*†
Are Postbiotic Supplements the New Prebiotics?
They are better thought of as the next step after prebiotics. The easiest way to understand the three is as a chain.
- Prebiotics are the food. They are fibers your body cannot digest, which travel to your gut and feed the bacteria living there.
- Probiotics are the helpers. They are live bacteria that add to the population already in your gut.
- Postbiotics are what the helpers make. When gut bacteria eat fiber, they produce useful compounds, and those compounds are what postbiotics are about.
A prebiotic supplement or a probiotic supplement covers one link in that chain. A postbiotic supplement goes straight to the end of it.
What Does a Prebiotic Supplement Do?
A prebiotic supplement gives the bacteria already in your gut something to eat. Your own digestive system cannot break down certain soluble fibers, so they pass through to the large intestine, where gut bacteria ferment them.
Bio Complete 3 uses two of these fibers, acacia gum and partially hydrolyzed guar gum (Sunfiber®), for a combined 450 mg per serving.
Why Isn’t a Probiotic Supplement Always Enough?
A probiotic supplement adds bacteria, but those bacteria have to survive the trip through your stomach first. Gundry MD’s position is that most probiotic bacteria are destroyed by stomach acid before they reach the gut.
Its answer is a spore-based probiotic. Bio Complete 3 uses Bacillus coagulans, a bacterium that can form spores, a dormant, protected state it can wake up from when conditions are right. Gundry MD says the spores are designed to survive heat, stomach acid, and bile on the way through digestion. The formula also includes a second probiotic, Bifidobacterium bifidum.*†
What Is a Postbiotic Supplement?
Postbiotics are new enough that an international panel of scientists, convened by the International Scientific Association for Probiotics and Prebiotics, only published a consensus definition in 2021. Supplement brands generally use the word more broadly, for the useful substances gut bacteria produce. The one getting the most attention is butyrate.
Butyrate is a short-chain fatty acid that gut bacteria make when they ferment fiber. A 2025 review in Frontiers in Nutrition describes it as “produced by the gut microbiome from indigestible carbohydrates.” It is also the main fuel for the cells lining your colon. A 2021 review in the International Journal of Molecular Sciences puts butyrate’s share of the energy those cells need at 70 to 80 percent. That number is why so many people are now searching for a butyrate supplement.
Why Choose a Tributyrin Supplement Over a Plain Butyrate Supplement?
Butyrate has one big drawback as a supplement. Taken by itself, it is cleared from the body within seconds to minutes.
Tributyrin solves that. It is three molecules of butyrate attached to a backbone of glycerol, which makes it a fat. A tributyrin supplement is stable, absorbed readily, and converted into butyrate gradually, so it works as a slow-release form of a compound the body would otherwise clear almost at once.*†
Butyrate even takes its name from butter, one of the few foods that contains it naturally. Bio Complete 3 includes 300 mg of tributyrin per serving.
What Is Gundry MD Bio Complete 3?
Bio Complete 3 is Gundry MD’s flagship gut health supplement. The company describes it as one of the first supplements to combine prebiotics, probiotics, and postbiotics in one daily formula, and says it has sold more than 10 million bottles since launching in 2020.*†
It was formulated by Dr. Steven Gundry, a former cardiothoracic surgeon, host of The Dr. Gundry Podcast and author of four New York Times best-sellers, including The Plant Paradox. “I designed this unique 3-pronged blend of probiotics, prebiotics, and postbiotics,” he says of the product.
As Gundry M.D. puts it, most probiotics only add bacteria. Bio Complete 3 is designed to feed good bacteria, add good bacteria, and support the gut environment itself, all in the same capsule.*†
What Is in Bio Complete 3?
Bio Complete 3 is Certified Vegetarian by the American Vegetarian Association and Certified Gluten-Free by GFCO. It is lectin-free, with no sugar, soy, dairy, or artificial sweeteners, and every lot is tested for microbial contaminants and heavy metals.
A quick checklist for choosing any gut health supplement:
- It tells you which parts of the chain it covers: prebiotic, probiotic, postbiotic, or all three
- It names its probiotic strains and explains how they survive stomach acid
- It lists the amount of each ingredient per serving
- It is batch tested for quality
What Do Bio Complete 3 Reviews Say?
Gundry MD’s 2025 press materials cite more than 2,400 positive reviews. Customers tend to describe changes in everyday comfort. One reviewer said the product “calmed things down greatly.” Another said the first thing she noticed was that bloating had diminished, and that her energy returned. Others mention more regular bowel movements and better digestion, enough to recommend it to family.*†
Individual results will vary. Users may have been compensated to share their honest experience.
The product has also been recognized in the 2025 Nourish Awards in the supplements category, where judges praised its “balanced, research-driven design.”
Who Should Consider a Gut Health Supplement Like Bio Complete 3?
Bio Complete 3 is aimed at adults, particularly those over 40, who deal with occasional bloating, irregularity, low energy, or cravings, and who have tried a basic probiotic supplement without noticing much. It may help support comfortable digestion and regularity* and help with occasional bloating.*†
Anyone with a medical condition, or who takes medication, should speak to a doctor first. Dr. Gundry says as much himself. “As a physician, I know that individual bodies can react differently to the very same compounds,” he says.
What Are the Pros and Cons?
Pros
- Combines a prebiotic, a probiotic, and a postbiotic in one daily formula
- Delivers butyrate as tributyrin, a stable, slow-release form
- Uses a spore-based probiotic designed to survive digestion
- Certified Vegetarian and Gluten-Free
Cons
- Results build over weeks, not days
- It is priced above basic probiotic supplements
- If you have a health condition, or take any medication check with your doctor before starting
How Do You Take Bio Complete 3?
Take two capsules daily with water. Dr. Gundry recommends taking it consistently for at least 90 days for best results.
Research on the formula is continuing. Gundry MD is running a gut-model study and a human clinical study on Bio Complete 3, with the human study scheduled to conclude in November 2026. Dr. Gundry’s next book, Feed Your Brain, due on February 23, 2027, looks at the connection between the gut and the brain.
Where to Buy Bio Complete 3, and Is There a Coupon?
Buy Bio Complete 3 from the official Gundry MD website, or on Amazon only when it is sold by the Gundry MD Store and fulfilled by Amazon. Listings on Walmart, Etsy, eBay, and other third-party sites may be counterfeit or expired and do not carry the guarantee. Purchases are covered by a 90-day purchase price guarantee, minus shipping.
You can use code PODCAST25 for 25% off regular-priced items. Valid until 4/9/27. Excludes My Account and subscription pricing, bundles, devices, and digital products. Cannot be combined with other offers.
Frequently Asked Questions
1. What is the difference between a prebiotic, a probiotic, and a postbiotic supplement?
A prebiotic supplement feeds your gut bacteria, a probiotic supplement adds bacteria, and a postbiotic supplement supplies the useful compounds those bacteria make, such as butyrate.
2. Is tributyrin the same as butyrate?
Tributyrin is three butyrate molecules joined to glycerol. The body converts it into butyrate gradually, which is why it is used as a slow-release butyrate supplement.
3. How long does Bio Complete 3 take to work?
Results vary from person to person. Dr. Gundry recommends taking it consistently for at least 90 days for best results.
4. How do I take it?
Two capsules daily with water.
5. Is Bio Complete 3 lectin-free?
Yes. It is also free of sugar, soy, dairy and artificial sweeteners.
6. Is it quality tested?
Every batch is tested for microbial contaminants and heavy metals. It is Certified Vegetarian by the American Vegetarian Association and Certified Gluten-Free by GFCO.
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
*All individuals are unique. Results can and will vary.
