The 14 best supplements for gut health and weight loss

If you’re on a health or weight loss journey, you may want to know which supplements actually support gut health and weight loss, as well as how to choose options that are worth your time and money. This guide breaks down what the research shows and what to expect.

Here are the main categories we’re exploring:

• Probiotics

• Prebiotics

• Synbiotics (probiotic + prebiotic combos)

• Digestive enzymes

• Fiber supplements

• Omega-3s

• Apple cider vinegar

• Other gut-supporting supplements

• Vitamins that help with digestion

Let’s look at these in more detail so you can decide what makes the most sense for your goals.

Supplements may support gut health and weight loss efforts, but they work best in conjunction with a healthy diet and lifestyle, rather than as standalone weight-loss solutions.

When considering which are the best supplements for gut health, you may wonder whether gut health supplements can actually help you lose weight, too. Here’s what to know about some popular choices:

See if you qualify

1. Probiotics

Obesity has been linked to imbalances in gut bacteria. Probiotics are helpful bacteria that support intestinal health, and research suggests they may also play a role in weight management.

They can help keep gut bacteria in balance, strengthen the gut barrier, and support the body’s natural immune responses. Gut microbes also help break down food and regulate cholesterol and blood sugar, make vitamins, and influence brain health. 

Several probiotics, including Lactobacillus, Bifidobacterium, and Saccharomyces, have been studied for their potential to help with excess weight. These microbes connect to metabolism and may influence the signals and inflammation linked to weight gain.

Research so far shows encouraging trends. In many clinical trials, people taking probiotics saw reductions in body weight and body mass index (BMI), and some trials also found decreases in waist size or body fat.

The most consistent results appeared when products combined multiple strains, especially mixes of Bifidobacterium and Lactobacillus, rather than using a single strain.

2. Prebiotics

Prebiotics are nutrients that your gut bacteria break down and use as fuel. When gut microbes digest prebiotics, they produce short-chain fatty acids that can influence the gut and other parts of the body through the bloodstream.

Two well-known types are fructo-oligosaccharides and galacto-oligosaccharides, which naturally occur in small amounts in certain foods.

Early research combining prebiotics with probiotics and lifestyle changes shows meaningful results. In one 3-month study of those following a reduced-calorie, high-fiber (prebiotic) eating pattern plus daily probiotic yogurt and regular exercise, participants saw significant improvements in weight and body composition.

Their gut bacteria also shifted toward more beneficial strains such as Lactobacillus, Bifidobacteria, and Bacteroidetes. These findings suggest that prebiotics can help nourish helpful gut bacteria and may support healthy weight changes.

3. Synbiotics (probiotics + prebiotics)

Synbiotics combine two things: live beneficial microorganisms (probiotics) and the specific “food” that those microorganisms, or your body’s own gut bacteria, can use to grow (prebiotics).

Early research shows that synbiotics may support gut health during weight-loss programs, even if they don’t directly increase weight loss. In a three-month clinical trial alongside a reduced-calorie, high-protein, low-carbohydrate diet, people taking a synbiotic didn’t lose more weight than the placebo group.

But the supplement did increase beneficial bacteria like Bifidobacterium and Lactobacillus. Some patterns also emerged, such as increases in Lactobacillus being linked with lower blood glucose.

This suggests synbiotics may help nourish helpful gut bacteria while you’re working on weight management.

4. Digestive enzymes

Digestive enzymes are substances your body naturally makes to break down fats, proteins, and carbohydrates so you can absorb nutrients from food. When someone has trouble digesting certain nutrients, enzyme supplements may help.

One established example is orlistat, but it’s not a digestive enzyme supplement. Orlistat (aka Alli or Xenical) is an FDA-approved medication that works by blocking the breakdown and absorption of dietary fat. Its weight-loss effects are mild, but it can help reduce risk factors associated with conditions like diabetes and heart disease. 

This success has motivated researchers to look at new supplements that block the digestion of carbohydrates or fats.

Some ingredients, such as acarbose and phaseolamine, have shown early, promising signs for weight effects, but many enzyme-blocking agents have not yet been tested in solid clinical studies.

At this stage, more evidence is needed before these products can be recommended for weight loss.

5. Fiber supplements (including glucomannan/β-glucans)

Research shows that adding fiber supplements to a reduced-calorie eating plan can lead to meaningful improvements in weight and metabolic markers.

In a study of adults with overweight or obesity, people who took fiber supplements alongside energy restriction saw greater reductions in body weight, BMI, fat mass, visceral fat, inflammation, and lipid levels compared to those who followed the diet alone.

A blend containing glucomannan, inulin, psyllium, and apple fiber produced the largest drops in BMI and body weight.

And in a 180-day trial in adults with obesity, a supplement containing glucomannan, inulin, and psyllium led to significant reductions in body weight, BMI, fat mass, and visceral fat compared to placebo.

Some specific fibers, like β-glucans, have been studied for their role in metabolic health. β-glucans are soluble fibers found in oats and barley. They may have benefits for insulin resistance, cholesterol levels, blood pressure, and obesity.

6. Omega-3 fatty acids (fish oil)

Omega-3 fatty acids are well-known nutrients with many general health benefits, but the research on their role in weight loss is mixed. A large review found inconsistent results: out of 20 trials, 11 found no effect on weight or body fat, while nine showed some benefits.

Because the findings vary and the studies differ widely in design, the overall evidence does not yet support omega-3 fatty acids as a reliable weight-loss supplement.

More research is needed to confirm how omega-3 supplements influence weight, fat loss, and other health measures.

7. Apple cider vinegar

Scientists have proposed many reasons vinegar might help with weight loss, by slowing how fast the stomach empties, helping the body use glucose more efficiently, supporting insulin sensitivity, and increasing satiety.

In a 12-week trial involving adults with overweight or obesity, daily apple cider vinegar at doses of 5, 10, or 15 mL led to significant reductions in weight, BMI, waist and hip measurements, and body fat ratio.

While early research is promising, experts note that much larger, long-term studies are still needed before strong conclusions can be made.

Since the evidence is still developing, apple cider vinegar may offer some support, but it’s not a guaranteed way to lose weight or improve your metabolism.

Some supplements for digestive health provide additional support for maintaining gut balance and promoting gut repair. Here are some options for you to consider if you’re looking for the best gut repair supplements on the market.

8. Vitamin D

Vitamin D is a nutrient your body can make when your skin is exposed to UVB sunlight, and you can also get it through food. Inside the body, vitamin D is converted into an active hormone that interacts with the vitamin D receptor, which helps regulate the function of certain genes.

One of vitamin D’s main target areas is the intestine. While it’s best known for supporting calcium absorption, research shows it may also help support gut health in other ways, like strengthening the gut barrier and reducing inflammation in the digestive tract.

People with obesity, type 2 diabetes, or metabolic syndrome often have lower vitamin D levels. But most studies show that vitamin D supplementation does not meaningfully improve metabolic markers except possibly in people who are deficient. Talk with a healthcare provider to determine if a vitamin D supplement is right for you and how much to take — too much vitamin D can be harmful.

9. L-glutamine

L-glutamine is often described as an amino acid for gut lining repair because it helps fuel the cells that line the intestines. Research suggests it may help support the gut barrier, especially during times of physical stress like illness, injury, infection, or surgery.

When the gut barrier is weakened, it can become more permeable (“leaky”), which may trigger inflammation. Glutamine may play a role in helping the lining recover and stay intact.

Research also links low glutamine levels with gut barrier disruption and inflammation, and shows glutamine supplements can improve intestinal barrier function and support recovery when the gut lining is under strain.

10. Berberine

Berberine has been widely studied in animals, cells, and humans for its metabolic effects. It can influence gut microbiota, affect glucose pathways, and help regulate cholesterol in human studies.

Berberine has also shown potential to impact obesity-related mechanisms, but much of the detailed evidence comes from preclinical models.

Human studies suggest it may support metabolic health, though more research is needed to confirm its role in weight management.

11. Collagen

Collagen peptides are easily absorbed forms of collagen commonly used in supplements. In a study of adults over 50, daily collagen supplementation led to meaningful reductions in body fat compared with a placebo.

While collagen is best known for skin benefits, this research suggests it may also support body-composition changes, though evidence is limited and specific to older adults.

Certain vitamins play key roles in gut health, digestion, and supporting the microbiome. Here’s an overview of vitamins that may help with digestion and what the science actually says.

12. B vitamins

B vitamins support energy production and metabolism, and they may also affect the composition of the gut microbiome. Gut bacteria can make several B vitamins, and high-dose B2 or B3 delivered to the colon has been shown to increase certain beneficial bacteria and overall microbial diversity.

But findings are mixed. Some studies show changes in gut bacteria, while others show none. Overall, B vitamins may help support a healthy gut environment, but their effects vary by vitamin type and how they’re absorbed.

13. Vitamin C

Vitamin C is an essential nutrient that acts as a powerful antioxidant and supports several functions. It helps your immune system by supporting B- and T-cells. Low vitamin C levels are linked to weaker immune defense and higher susceptibility to infections.

Because infections can lower vitamin C levels even further, getting enough through diet and sometimes supplements may help support overall immune health.

Some early research also suggests vitamin C may influence gut bacteria. In one small study, healthy adults who took 1,000 mg of vitamin C daily for two weeks had measurable shifts in their gut microbiota, including increases in certain bacterial groups linked to gut health and anti-inflammatory effects.

14. Magnesium

Magnesium is important for immune function and inflammation, which both affect gut health. In animal studies, magnesium deficiency triggered inflammatory changes and shifted the makeup of gut bacteria.

This mineral is also used as a laxative to treat constipation. In a study of people with mild to moderate chronic constipation, taking magnesium three times daily for 28 days led to greater overall improvement compared to a placebo. It significantly increased the number of spontaneous bowel movements, improved stool form, and shortened how long it takes stool to move through the colon.

While magnesium can help with constipation, side effects may include diarrhea, stomach cramps, or low blood pressure. Consult your healthcare provider before taking magnesium for constipation for longer than a week. People with kidney disease, muscle-related conditions, or those taking certain medications should also check with a healthcare professional before using it.

Whole foods can provide natural alternatives to digestive enzymes and supplements for digestive health. Here are some options to help you decide when food or supplements may work best.

Probiotic-rich foods

For a food to provide probiotics, it needs to contain specific microorganisms that have proven health benefits. Yogurt is one well-known example of a fermented food that contains live cultures, including Lactobacillus bulgaricus and Streptococcus thermophilus.

Other fermented foods, such as cheeses, kimchi, kombucha, sauerkraut, miso, and pickles, often contain live cultures but not necessarily probiotic microorganisms.

Probiotic strains can also be added to unfermented foods. Products such as milks, juices, smoothies, cereals, nutrition bars, and baby formulas may contain added probiotics, which should be listed on the label along with the specific strain and the number of live microorganisms.

Prebiotic foods

Prebiotic foods help nourish beneficial gut bacteria. They naturally occur in many plant-based foods, including asparagus, sugar beet, garlic, chicory, onions, Jerusalem artichoke, wheat, honey, bananas, barley, tomatoes, rye, soybeans, peas, and beans.

Cow’s milk also contains certain prebiotic components. More recently, seaweeds and microalgae have been identified as natural prebiotic sources as well.

Why whole foods can be better

Whole-food diets are built around minimally processed, plant-based ingredients. They’re consistently linked to better health outcomes compared to diets heavy in processed foods, refined sugar, salt, and saturated fat.

Whole food eating patterns naturally include more fiber, micronutrients, phytochemicals, complex carbohydrates, and plant proteins, all of which tend to be limited in heavily processed foods.

Research shows that the quality and balance of macronutrients like carbohydrates, proteins, and fiber can meaningfully affect appetite, metabolism, and overall health.

Diets that are lower to moderate in protein and higher in complex carbohydrates have shown notable metabolic and even lifespan benefits in animal studies. 

Gut health plays a role in how the body manages weight because bacteria in the gut microbiome help with nutrient metabolism, energy use, hormone activity, and inflammation.

The gut microbiome is the collection of microorganisms that live in your digestive tract, along with their genes and the compounds they produce.

Research has linked changes in the gut microbiome to obesity and to the body's response to weight-loss efforts. These are key ways gut health may affect weight loss:

• Gut bacteria help regulate nutrient and energy metabolism: There’s a clear relationship between gut flora, how nutrients are metabolized, and how the body uses energy. These metabolic interactions may influence weight.

• Gut microbes may produce short-chain fatty acids that affect metabolism: Short-chain fatty acids are one proposed mechanism through which gut bacteria may play a role in obesity and weight regulation.

• Gut bacteria may influence appetite-related signals: Probiotics, prebiotics, and synbiotics may alter the release of hormones, neurotransmitters, and inflammatory factors that can impact eating behaviors linked to weight gain.

• The gut microbiome changes during weight-loss treatments: The diversity and composition of gut bacteria also shift in response to different obesity treatments. 

Inflammation may also affect the body’s tendency to gain weight. In animal studies, repeated episodes of acute inflammation caused long-lasting increases in inflammatory markers inside fat tissue.

When these animals later ate a high-fat diet, they gained more weight and had worse insulin sensitivity than animals without earlier inflammation.

These findings come from animal models, but they show how inflammation can change the body’s response to food and may increase susceptibility to weight gain.

Get started

Choosing a good probiotic or prebiotic supplement can feel overwhelming, and the quality really does matter. Based on what researchers have found, here are the key things to look for when you’re trying to pick a product that’s safe, reliable, and more likely to be effective:

• Check for strain specificity: Not all probiotic strains work the same way. Their effects can vary a lot depending on the exact strain, so look for products that clearly list the specific strains they use, not just the species name.

• Look for clear dosing information: Because there’s no universal standard for probiotic or prebiotic doses, choose products that tell you exactly what dose you’re getting. Some supplements labels hide the amounts of individual ingredients by listing a total dose of their “proprietary blend.” Avoid supplements that don’t provide clear information.

• Choose brands with strong quality control: Product quality can vary based on how the supplement is manufactured and stored. Pick companies that are transparent about their processes or offer third-party testing to ensure the probiotics remain viable.

• Know how the product is regulated: Probiotics and prebiotics may be sold as supplements, foods, or even medicines, depending on the country. This means the rules around quality and approval can differ. Being aware of this helps set realistic expectations.

• Be mindful of safety if you have health conditions: People who are immunocompromised, critically ill, very young, or using central venous catheters may have a higher risk of complications from certain probiotic or prebiotic products. In these cases, medical guidance is especially important.

• Consider potential interactions: These supplements may interact with medications, which can affect treatment outcomes. If you take prescription drugs, ask your healthcare provider about possible interactions before taking a gut health supplement.

Keeping these tips in mind can help narrow down the best supplements for digestion, especially when comparing different brands and formulas.

A healthy gut supports many functions beyond just digestion and weight management. When the gut microbiome is functioning well, it can:

• Help you get more from food: Gut bacteria help break down certain parts of plant foods that the human body can’t digest on its own, which can support digestion and nutrition.

• Make helpful compounds from fiber: Gut bacteria turn indigestible fibers into short-chain fatty acids, which help fuel the intestinal lining and can influence immune responses in the gut.

• Supports immune balance: The gut microbiota interacts closely with the immune system and helps “train” it. One example is supporting the development of regulatory T-cells, which are involved in maintaining immunity.

• May play a role in gut-related conditions: Researchers are actively studying how shifts in the gut microbiota (often called dysbiosis) relate to conditions like irritable bowel syndrome (IBS), inflammatory bowel disease, obesity, and diabetes. In many cases, it’s still unclear what changes are a cause versus an effect.

Gut symptoms are extremely common. Mild bloating or gas can be uncomfortable, though it may not be a serious issue. But some symptoms can be signs of a gut health issue that needs medical attention.

Talk to a healthcare provider if you’re experiencing:

• Anorexia

• Unintended weight loss

• Trouble swallowing

• Ongoing vomiting

• Severe abdominal pain

• Severe or persistent diarrhea

• Black, tarry stools

• Bright red blood in the stool

It’s especially important to get checked if these symptoms show up in someone over 50 who hasn’t had a colonoscopy, or if there’s a family history of colorectal or other gastrointestinal cancers.

Also worth noting: Gut health issues don’t always present with obvious stomach symptoms. If you’re dealing with ongoing fatigue, poor sleep, or persistent mood changes, it may be worth discussing with a healthcare provider.

Early research suggests the gut microbiome can influence sleep and mental state through the gut–brain axis, and gut inflammation has been linked to sleep loss and circadian disruption.

Gut imbalance can also show up as autoimmune diseases or food intolerances. Many studies link autoimmune conditions to gut microbiome imbalances. The gut microbiome may also influence lactose intolerance symptoms, especially in those who notice recurring bloating, discomfort, or abdominal pain after dairy.

If these issues feel persistent, are worsening, or are hard to manage on your own, it’s a good reason to bring them up with a healthcare provider.

Gut health supplements can be a helpful starting point, but they don’t work for everyone. Weight can also be difficult to manage, even with consistent nutrition and exercise. If you haven’t seen the changes you hoped for, prescription weight-loss medications may be an option.

A Ro, you can start with a quick online visit to see a provider and check if you qualify for prescription weight-loss treatment, including GLP-1 and GIP medications like Ozempic and Wegovy (semaglutide).

These medications work by reducing appetite and increasing feelings of fullness, which can make it easier to stick with long-term weight-loss habits.

If treatment is appropriate, a licensed provider will recommend the right plan and support you throughout the process, including helping navigate insurance coverage when available.

FDA-approved weight-loss medications

Several FDA-approved medications are available for weight management. These include short-term appetite suppressants (phentermine, diethylpropion) and long-term options such as:

• Orlistat (Alli, Xenical): reduces fat absorption

• Phentermine-topiramate (Qsymia): decreases appetite

• Bupropion-naltrexone (Contrave): decreases appetite and cravings

• Liraglutide (Saxenda): increases fullness and satiety

• Semaglutide (Wegovy): GLP-1 receptor agonist

• Tirzepatide (Zepbound): GLP-1 and GIP receptor agonist

• Gelesis100 (Plenity): increases fullness

• Setmelanotide (Imcivree): for certain rare genetic obesity conditions

Each has different mechanisms and is appropriate for different situations. 

Getting started with weight-loss medication

Here’s how Ro makes it easy to understand if prescription weight loss treatment is right for you:

1. Start your online visit: Answer a few questions about your health and goals online. You’ll learn whether you’re eligible within about two days.

2. Provider writes an Rx (if appropriate): A licensed provider reviews your information and prescribes the right GLP-1 treatment if you qualify. With insurance, most people begin within 2–3 weeks; without insurance, often within a week.

3. Check your insurance coverage, or pay cash: Ro handles insurance navigation and paperwork. If you’re covered, a prescription goes to your pharmacy or is processed through Ro’s pharmacy. If not, Ro will appeal on your behalf or recommend alternatives.

4. Start your treatment: If prescribed, the medication ships to your home or is available for pickup.

5. Get support to keep on track: You’ll have ongoing access to your care team, regular check-ins, and guidance to help you stay consistent throughout your treatment.

See if you qualify

Gut health plays a role in digestion, inflammation, and weight. Supplements can help, but they’re not a replacement for healthy daily habits. 

Here’s what to remember:

• Some gut health supplements can be helpful: Options like probiotics, prebiotics, and fiber blends may support digestion and weight management efforts, but results can be mixed.

• Quality and formulation matter: The strain, dosage, and type of supplement all influence how well it may work, especially for gut health supplements.

• Digestive needs vary from person to person: What helps one person’s gut or digestion may not work for someone else, and different symptoms may require different types of support.

• You have medical options if supplements aren’t enough: If you’re still struggling with weight despite your efforts, Ro offers access to prescription weight-loss medications to those who qualify.

The best supplements for gut health and weight loss will depend on your specific needs.