Bio Complete 3 Reviews: Effective for gut health and weight management?

Among U.S. adults, probiotics and prebiotics together constitute the third most commonly used dietary supplement, after vitamins and minerals.1 It may have something to do with the fact that around 40% of Americans experience gut health symptoms that significantly disrupt their lives.46 When a problem is that prevalent, so is the pursuit of a readily available remedy.

The subject of this review, Gundry MD Bio Complete 3, is one such possible remedy. Combining prebiotics, probiotics, and a postbiotic, it’s a three-pronged approach to digestive health aimed at supporting the gastrointestinal lining and the healthy bacteria that thrive in one’s gut microbiome. Having examined the science behind Bio Complete 3’s formulation, we offer here our analysis of and testing experiences with the product so you can determine whether it’s the right remedy for you.

Bio Complete 3 consists of three proprietary blends containing promising ingredients that mostly fall short in terms of dosage or compelling research support. Specifically, its prebiotic blend is several grams short of clinically relevant amounts, and its probiotics lack strain-specificity. That being said, its 300mg dose of tributyrin does align with clinical studies, and its probiotics are well-studied on the species level. They may hold potential to support gut lining and a healthy gut microbiome. But at the one-time-purchase tier, the price tag still sits higher than that of better-formulated competitors such as Seed and Ritual, which we think are better options for most people.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions involving staying healthy and living healthier lifestyles.

To provide you with an unbiased review, we extensively researched and evaluated Bio Complete 3 by examining more than 55 scientific studies relevant to its ingredients. We also ordered the product ourselves so that we could assess the customer experience and measure Bio Complete 3 against top competitors across the probiotic landscape. Our combined evaluation of theoretical and practical knowledge areas allows us to present you with the most comprehensive evaluation possible, and empower you to make the best-informed consumer decision.

Additionally, like all health-related content on this website, this review was thoroughly vetted by one or more members of our Medical Review Board for accuracy, and has been continually reevaluated in the light of new research, ensuring that it remains up-to-date.

We based our evaluation of Bio Complete 3 on the following four criteria:

• Efficacy: how well the formulation aligns with available research evidence
• Safety: the degree to which the product may pose potential health risks
• Cost: the product’s affordability relative to the probiotic landscape
• Customer experience: the measures by which the company facilitates the customer journey

Here’s how Gundry MD and Bio Complete 3 fared in each criterion.

Safety

Gundry MD manufactures its products in GMP-certified facilities, subjects its products to third-party testing, and publishes the test results to its product pages — all the baseline safety measures we like to see. So we’re off to a good start, safety-wise.

And it gets better, because two of Bio Complete 3’s ingredients are FDA-affirmed GRAS (“Generally Recognized as Safe”): the acacia gum and the tributyrin.4 40

As for the remaining ingredients:

• PHGG: In a 2016 randomized clinical trial with 108 patients, a 6g dose of PHGG produced no adverse effects.20 Bio Complete 3’s dose is way under 6g and therefore poses even less risk.
• Probiotics: The B. bifidum and B. coagulans species hold Qualified Presumption of Safety (QPS) status with the European Food Safety Authority.41 42 QPS is conceptually similar to GRAS.

On the safety front, Bio Complete 3 is almost as ideal a supplement as you can get. The primary factors subtracting from a perfect 10 score relate to the potential side effects and risks associated with probiotics in general, which we discuss later in this guide.

Efficacy

With its label alone, Bio Complete 3 presents a mixed bag. On the one hand, it clearly shows that the formulation uses well-studied probiotic species (Bacillus coagulans and Bifidobacterium bifidum) as well as recognizable support ingredients for those species (Corebiome, PHGG, and tributyrin). But on the other hand:

• Its Bifidobacterium bifidum strain is unspecified. A critical omission because probiotic efficacy is strain-specific.2 Other strains of Bifidobacterium bifidum may have demonstrated gut health effects in clinical research,32 33 but we can’t say whether Bio Complete 3 uses a well-studied strain, and Gundry’s customer support team is unforthcoming about the matter.
• Its Bacillus coagulans strain (ProDura) lacks strain-specific evidence. An exact-term search on PubMed yields no results related to probiotics.
• Colony-forming units (CFUs) are not listed. That is, Gundry doesn’t specify how many live microorganisms in its product are capable of reproducing, which leaves a lingering question as to Bio Complete 3’s true ability to achieve benefits.3 Previously, we were able to verify with Gundry customer support that the probiotic blend totaled 2 billion CFU, but in a recent correspondence, they were unwilling to divulge the count. In a pessimistic view, their caginess could imply that Bio Complete 3 no longer contains 2 billion CFU of live probiotics. But even if we aren’t being pessimistic, we can no longer validate the count we’d previously reported.
• The prebiotic blend is severely underdosed. Of acacia gum and partially hydrolyzed guar gum (PHGG), it contains just 450mg altogether, when clinical studies point to a minimally effective dose exceeding multiple grams of each.35 20

The only ingredient in the formulation that’s clinically dosed for gut health is the tributyrin, a postbiotic that produces butyrate and therefore may support colon cells, the intestinal barrier, anti-inflammatory activity, and other potential areas of gut health.5 6 But Bio Complete 3 is hardly the only probiotic supplement that contains a clinical dose of tributyrin. Ritual does, too.

Apart from the tributyrin, we suppose it’s possible that Bio Complete 3’s probiotic blend is, in fact, well-formulated, but there’s no knowing for certain. Right now, then, all we have to go on is species-level plausibility.

Cost

For non-members, a one-month supply of Bio Complete 3 costs $69.95 on a one-time-purchase basis, which is significantly pricier than better-formulated competitors such as Seed ($49.99).

But Gundry has a saving grace: membership pricing. Registration is free, and it gains you access to steeply discounted prices:

• 1 bottle: $49.95
• 3 bottles: $134.85 ($44.95 per bottle)
• 6 bottles: $251.70 ($41.95 per bottle)

Prices are even better if you combine membership pricing with a subscription. Indeed, even a one-bottle membership subscription outdoes Seed and isn’t much pricier than another competitor, Ritual, neither of which offers bulk pricing:

There are some important product caveats here related to efficacy, as both Seed and Ritual offer products that are more likely to be effective. Gundry just has a potential cost edge here, at least in a vacuum.

Customer experience

Gundry MD operates live chat support, which is a major plus. In our experience, an agent typically connects within a minute and provides succinct answers in as much time. We couldn’t always pry out the answers we wanted (i.e., about CFUs and strain specificity), but we can’t fault the customer support team for their employer’s directive about protecting proprietary information.

In other areas of Gundry’s customer experience, too, we’ve found practically nothing to vex us. There isn’t anything obnoxious about the website or checkout process: they’re as straightforward as you’d want from an online merchant. Maybe we could complain about having to register an account, but it’s such a small thing that reaps such a big discount that we’d only be picking a nit for nitpicking’s sake. Gundry hasn’t even bothered us with marketing emails after the fact.

Gundry’s dosing protocol shouldn’t cause discontent, either. The two-capsule regimen is preferable to others, and it’s equal to Seed’s. Among top alternatives, only Ritual’s one-cap dose is more convenient.

Bio Complete 3 is a probiotic-based dietary supplement that purportedly reduces cravings, eases digestion, and boosts energy — claims that we’ll scrutinize shortly. Each bottle contains 30 servings (60 capsules, or a one-month supply) with two capsules taken once daily.

Dr. Steven Gundry, a heart surgeon for over 30 years, founded Gundry MD with a focus on overall gut health as a proponent of healthy weight management. His "holobiotics" approach involves administering a combination of prebiotics, probiotics, and postbiotics to support “good” bacteria that face off against lectins, pathogens, and gut yeasts, which can harm proper cell function, cause illness and infection, and hinder healthy digestion.38 39

As a company, Gundry MD has an A+ rating with the Better Business Bureau (BBB) and is BBB-accredited. The majority of online customer reviews of Bio Complete 3 are positive, with most 5-star reviews reporting improvements in digestion and energy. Negative reviews typically come from people who have experienced unpleasant side effects, such as bloating or gas, which are common complaints among those who start a probiotic supplement.

Our Bio Complete 3 purchasing experience

We ordered Bio Complete 3 directly from the Gundry MD website. Between the shopping cart and checkout screen, we encountered several upselling opportunities.

Gundry MD makes it easy to track your order from your account interface and gives a link to your tracking information in an email confirmation. We received frequent order status emails.

We had mostly positive experiences interacting with customer support, too. The live chat option is a huge plus. We were able to connect to a live representative within a minute and just as quickly get our question answered. Emailing is slower, naturally. It took a couple of days to get a response, and our question wasn’t fully answered.

The ingredients in Bio Complete 3 are intended to support the growth and colonization of the beneficial gut bacteria we need, as well as to support the lining of the gastrointestinal tract. They’re combined as three proprietary formulas that each serve a specific broad function:

Probiotics

Probiotics are bacteria that restore and replenish gut flora. Generally, they’ve been found to help with several common conditions in scientific research:

• Antibiotic-associated diarrhea8
• Bacterial vaginosis9
• Inflammatory bowel disease10
• Irritable bowel syndrome11
• Constipation12
• Periodontal disease13

But probiotics encompass a vast and varied landscape of different species and strains. Members of a species share basic characteristics, whereas a strain confers specific benefits, so a discussion of a probiotic’s true health potential centers on strain designations.

And here we encounter one major obfuscation in the Bio Complete 3 formulation, because while its 22mg probiotic blend consists of two species, only one of them is specified to the strain level.

It’s not that the probiotic blend is a critical weak point, as it at least contains species that have generally produced excellent gut health outcomes in research. Rather, it’s more of an uncertainty, like a machine part of unknown reputation and origins: you can’t be sure of its quality. And the uncertainty widens further by the fact that Gundry MD lists the blend by weight rather than colony-forming units (CFUs). With the kinds of probiotic species we’re dealing with, you probably need at least 2 billion CFU per serving to see meaningful differences in your health,2 but there’s no telling anymore whether Bio Complete 3 hits the mark, and in recent correspondence, the customer support team was unwilling to divulge what the company deems to be proprietary information.

Probiotic dose specification is a point in which almost every one of Gundry’s top competitors does better. Ritual, for instance, lists both weights and CFUs, as does Seed, and they aren’t clandestine about the strains they use.

Prebiotics

With the prebiotic blend, there’s no question: it is a weak point. The problem is that the dose is too light, and that’s putting it too lightly.

Ideally, with many prebiotics, you want multiple grams of each one to feed your beneficial gut bacteria, which would then break down the prebiotics into the short-chain fatty acids (SCFAs) that can help in areas such as:14

• A balanced gut microbiota15
• Cardiovascular disease16
• Irritable bowel syndrome with constipation17
• Colorectal cancer risk18
• Inflammatory bowel disease19

The prebiotics in Bio Complete 3, acacia gum and partially hydrolyzed guar gum (PHGG), have been shown to help in these and other areas,20 34 but at daily intakes of 5–10g.21 35 Bio Complete 3 provides only 450mg — not even a tenth of the lower end. The meager amount may be fermented to a small extent and may produce some SCFAs, but there’s no evidence that it can confer the sorts of benefits that a clinical dose might.

Postbiotics

Postbiotics refer to the byproducts made by the healthy bacteria in your gut.22 They include, but aren’t limited to, amino acids, vitamins, and SCFAs such as butyrate.23 Postbiotics are found in fermented foods like kimchi, kefir, and tempeh.

Bio Complete 3's postbiotic component is tributyrin, with 300mg in each daily dose: a clinically relevant amount, and the same as you’ll find in better-formulated Ritual Synbiotic+.5 Research on tributyrin itself is limited, with most being animal studies or unpublished trials for the manufacturer,26 but it still holds promise. Tributyrin, after all, is a butyrate precursor, and as such it supports butyrate-related benefits in areas like intestinal lining, bloating, loose stools, constipation, and gas.24

Tributyrin’s role as a butyrate precursor may even support Gundry’s claim that Bio Complete 3 can assist with energy and cravings. That’s because butyrate, as well as other short-chain fatty acids, has been found in animal studies to influence host metabolism and promote metabolic benefits through certain brain targets, some of which are involved in appetite control.28 27

So, while we can’t confirm that Bio Complete 3 will keep you and your appetite well-regulated, we acknowledge that it may potentiate mechanisms that make such regulation possible.

As a probiotic supplement, Bio Complete 3 has some potential to help healthy adults looking to improve their digestive health. After all, substantial evidence indicates that probiotics in general may improve digestion and reduce gastrointestinal discomfort,29 30 while fiber, probiotics, and tributyrin can work together to support your gut lining and immune system.

But there are also some people for whom a probiotic would be contraindicated:

• The immunocompromised or seriously ill: Per the National Center for Complementary and Integrative Health, “The risk of harmful effects from probiotics is greater in people with severe illnesses or compromised immune systems.”1 The reason is that probiotics are living organisms, and in people with immunocompromise or critical illness, they can effectively behave like opportunistic pathogens.
• People with impaired intestinal integrity: Probiotics may be beneficial when confined to the GI tract, but in people with impaired intestinal integrity, the otherwise helpful bacteria may enter the bloodstream, where they can cause harm. (Note: the same goes for people with indwelling central venous catheters.)31

Even among people who might benefit from probiotics, one should regard supplementation with measured expectations. A product formulated for the general public won’t help everyone, and it isn’t likely to make a meaningful difference in serious chronic inflammatory conditions such as Crohn’s disease. And even among products formulated for the general public, there are much better options, like Seed and Ritual Synbiotic+.

Alternatively, if you’re keen on trying a probiotic but find that a common OTC product is a poor fit, you might consider an at-home test for your gut microbiome. A good option there is Viome, which can formulate customized probiotics that meet your exact needs.

Also, and as always, it’s a good idea to speak with your doctor before starting a probiotic, or really any supplement.

The active ingredients Bio Complete 3 have been well-tolerated in scientific research studies, and the doses are all within safe limits. Plus, two of the ingredients (acacia gum and tributyrin) are FDA-affirmed GRAS,40 and the two probiotics hold Qualified Presumption of Safety status with the European Food Safety Authority.41 42

That’s not to say that side effects can’t arise. In fact, side effects are common, albeit minor, and they include:

• Increased flatulence
• Bloating
• Indigestion or mildly upset stomach
• Loose stool

Such side effects typically resolve within a couple days of starting a probiotic supplement.

Compared to other products with a pre-, pro-, and postbiotic makeup, Bio Complete 3 falls on the pricey end, at least as a one-time purchase. But once you account for Gundry’s steep membership/subscription discounts, the price looks more enticing:

The My Health membership brings the price down below that of Seed’s, and certain purchasing options are less costly than even Ritual. Add to that: every one of the purchasing options clears Gundry’s $49 free-shipping threshold, and every Gundry order is protected by a 90-day satisfaction guarantee — three times longer than either Ritual or Seed.

On price, then, Gundry MD Bio Complete finally has a clear advantage over its best competitors.

On the face of it, Bio Complete 3 looks like an underwhelming probiotic supplement. Were it clearer about its strains and doses, or more generous with its prebiotic blend, perhaps it would hold up better on the competitive landscape. As it stands, though, there are better options out there: