Can These 7 Supplements Help With Obesity?
Published on August 14, 2026
Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.
Weight loss supplements are seemingly everywhere, promising to reduce hunger, boost metabolism, or help the body burn more fat. Those promises can be tempting, especially when you’re already practicing healthy weight management habits but aren’t seeing the progress you’d hoped for. Research on supplements for obesity is limited, and most haven’t been shown to work well for weight loss.
For people who are deficient in certain nutrients, supplements may help correct that gap, says Cory Rice, DO, a board-certified internal medicine physician practicing in Dallas. When it comes to weight loss, some supplements may be beneficial when combined with regular exercise, healthy meals, and other lifestyle changes, he says. Still, because they aren’t regulated in the same way as prescription medications, the quality and labeling of supplements can vary, making it difficult to know exactly what you’re taking.
Here’s what the evidence says about several popular weight loss supplements and why it’s important to talk with your healthcare team before taking one.
1. Glucomannan
Glucomannan is a soluble fiber made from the root of the konjac plant. It absorbs water and expands in the stomach, which may help you feel fuller and eat less, says Sean Arora, MD, a board-certified family medicine physician based in Washington state, and medical director at Trimi, a telehealth platform offering compounded glucagon-like peptide-1 (GLP-1) medications for weight management.
What Studies Have Found
One review of 10 studies found that people who took at least 5 grams (g) of glucomannan daily for 12 weeks or longer lost an average of about 7 pounds (lbs) and had slight decreases in body mass index (BMI) and waist size. But many study participants were also cutting calorie intake or making other weight loss changes, so it’s unclear how much of the benefit came from glucomannan alone.
In another trial of 42 people, those who took two 250-milligram (mg) glucomannan gummies daily for two weeks reported feeling less hungry and had a small decrease in waist size compared with those who took a placebo (an inactive supplement). The study was brief, and more research is needed to know whether those results last.
Safety and Side Effects
Glucomannan can expand and cause choking or block the esophagus (the tube that carries food from your mouth to your stomach), Dr. Arora says. This can occur especially when it’s taken in tablet forms, though powder and capsule forms haven’t been linked to this issue. Choose a form of glucomannan supplement you can easily swallow, and take it with at least 8 ounces of water. People who have trouble swallowing should avoid this supplement, says Arora.
Glucomannan may also cause bloating and constipation, especially in people who are taking certain obesity medications, such as GLP-1 receptor agonists, that slow digestion.
2. Green Tea Extract
This supplement is a concentrated form of green tea. It contains antioxidants called catechins, mainly epigallocatechin gallate, and often caffeine. These compounds may slightly increase metabolism and help the body burn fat, says Rekha Kumar, MD, an obesity medicine specialist at Weill Cornell Medicine in New York City.
What Studies Have Found
Research so far shows only minimal weight loss in most adults with obesity, and green tea extract shouldn’t be considered an effective obesity treatment on its own, Dr. Kumar says.
One review of studies involving about 3,800 people found that green tea extract helped people lose a small amount of weight and slightly lower their BMI and body fat. Another review found that adding green tea extract to exercise offered only a very small weight loss benefit compared with exercise alone.
Safety and Side Effects
“Green tea extract may cause insomnia, nausea, and palpitations [a racing or pounding heartbeat],” Kumar says.
High doses of green tea extract, especially when taken on an empty stomach, have been linked to liver damage. People with liver disease or those taking medications that affect the liver should avoid high doses of green tea extract and talk to their healthcare professional before using this supplement, Arora notes.
3. Apple Cider Vinegar
Few kitchen staples have gained as much attention for weight loss as apple cider vinegar (ACV). It’s made from fermented apples and contains acetic acid, which may help reduce appetite and help you feel fuller, Arora says.
It’s also believed to slow how quickly food leaves the stomach, which could help extend that feeling of fullness, Kumar notes, though the evidence isn’t solid.
What Studies Have Found
Most studies show that ACV leads to only modest weight loss and is unlikely to work well on its own, Dr. Rice says.
One review of studies with nearly 800 adults who were overweight, had obesity, or had type 2 diabetes found that those who took about 2 tablespoons of ACV daily for 4 to 12 weeks lost an average of about 16 lbs, or 9 percent of body fat, and had slight decreases in BMI and waist size. The researchers said ACV may offer a short-term boost as part of a weight loss plan, but it should not be used as a treatment on its own.
Safety and Side Effects
ACV can worsen acid reflux and irritate the throat or esophagus, Rice says. Taking it undiluted may also wear away tooth enamel.
It can lower potassium levels and interact with certain diabetes medications, like insulin, says Kumar, so talk with your healthcare team first if you’re considering adding it to your routine.
4. Caffeine
Caffeine is a widely used stimulant naturally found in coffee, tea, and cocoa. It’s also added to many energy drinks and weight loss supplements for obesity.
The theory behind caffeine’s weight loss reputation is that it may increase metabolism, help the body burn fat, boost energy, and reduce appetite, Kumar says.
What Studies Have Found
While there’s some science behind the claim that caffeine may help the body burn slightly more energy and use fat for fuel, research on whether it reduces hunger is mixed.
Its impact on weight is also hard to measure, since most studies testing caffeine for weight loss have combined it with other ingredients, like ephedrine, guarana, or citrus extracts, rather than testing it alone. So, it’s hard to say how much of any benefit comes from caffeine itself versus the other ingredients it’s combined with.
Even when caffeine may help the body burn a few more calories, the effect is small and often wears off as your body gets used to it, Kumar says.
Safety and Side Effects
Caffeine is generally considered safe for most adults in amounts up to 400 to 500 mg per day, roughly what you’d get from four to five cups of coffee.
Possible side effects include a faster heart rate, high blood pressure, anxiety, and trouble sleeping, Arora says. People with these conditions or with heart disease should use caffeine cautiously, he notes.
Some research suggests caffeine sensitivity increases with age. One study found that coffee drinkers ages 65 to 70 took 33 percent longer to metabolize caffeine than younger participants. The longer caffeine stays in your system, the higher the chance of unpleasant side effects like jitteriness, irritability, and anxiety.
5. Berberine
Often nicknamed “nature’s Ozempic,” this plant compound commonly extracted from barberry and goldenseal, has a long history of use in herbal medicine. Berberine may help the body respond better to insulin, especially in people with insulin resistance or diabetes, which could lead to some weight loss, Rice says.
What Studies Have Found
Research so far shows minimal and inconsistent benefits. One review of 23 studies found small reductions in weight, BMI, and waist size. Another review found that berberine supplementation was tied to reduced waist size but no clear change in weight or BMI. In this second review, people typically took between 770 and 1,600 mg a day for about nine weeks to six months.
Larger studies are needed before berberine can be recommended as a standard obesity treatment, Arora says.
Safety and Side Effects
Some people experience diarrhea, constipation, and stomach pain with berberine, Rice says, and these side effects are more likely to occur at doses above 300 mg a day.
Berberine may also interact with diabetes medications, blood thinners, and medications that suppress the immune system, so talk with your healthcare professional before taking it, Arora notes.
6. Garcinia cambogia
Garcinia cambogia is a tropical fruit that grows in parts of Asia, Africa, and the Pacific Islands. Its rind contains hydroxycitric acid, which may reduce hunger and limit how much fat the body makes from carbohydrates, Arora says.
What Studies Have Found
Study results are mixed. In one trial, 89 women who were overweight took either Garcinia cambogia (2.4 g a day before meals) or a placebo for 12 weeks, while following a reduced-calorie diet. Those taking Garcinia cambogia lost about 8 lbs on average, compared with about 5 lbs in the placebo group, though the supplement didn’t seem to curb appetite or help people feel fuller. In another trial, 135 people took either 3 g of Garcinia cambogia daily or a placebo for 12 weeks while following a high-fiber, low-calorie diet. Both groups lost weight, about 7 lbs in the Garcinia cambogia group and 9 lbs in the placebo group.
One review of 12 studies involving about 700 people found that those taking Garcinia cambogia over 2 to 12 weeks lost about 2 lbs more than people taking a placebo. But when researchers looked only at the two best-designed studies, the supplement didn’t appear to help people lose more weight than a placebo. Many studies were also of low quality, making it difficult to confirm whether Garcinia cambogia is linked to weight loss.
Safety and Side Effects
Headache, nausea, and diarrhea can occur when taking this supplement, Kumar says. It has also been linked to serious liver damage, though this is very rare.
Garcinia cambogia may also interact with certain antidepressants by raising serotonin levels (a brain chemical that affects mood), says Arora. Too much serotonin in the body, called serotonin syndrome, can be dangerous, so discuss this supplement with your healthcare professional before taking it.
Researchers also do not know whether Garcinia cambogia is safe to use for a long time because studies have not followed people long enough.
7. Whey Protein
Protein supplements are best known for helping build muscle and preventing the loss of muscle mass in some people, but now they’re increasingly being marketed for weight loss. They come in several types, including whey, casein, soy, and pea, though whey protein has been studied the most for weight loss.
Protein may help you feel full longer and eat less, which may help you lose weight, Kumar says. Your body may also use a little more energy digesting protein than it does digesting carbohydrates or fat, which may help you burn a few extra calories, she notes.
Protein supplements may also help people taking GLP-1 medications protect muscle during weight loss, Kumar says.
What Studies Have Found
One review of studies involving nearly 1,900 people found that whey protein led to small reductions in BMI, body fat, and waist size. The benefits were strongest when people also reduced calorie intake and did resistance exercises, such as lifting weights. Whey protein contains calories of its own, so simply adding protein supplements to your usual diet without eating less or exercising can offset its weight loss benefits and contribute to weight gain.
In an eight-week study, researchers assigned 60 older women who were overweight or had obesity to either a calorie-reduced diet alone or a calorie-reduced diet with 20 g of regular or hydrolyzed whey protein each day. Women taking hydrolyzed whey, a form that has been broken down into smaller protein pieces, lost about 5 lbs on average, compared with about 2 lbs in the diet-only group.
Protein needs vary, though experts recommend ingesting 1.2 to 1.6 g per kilogram (kg) of body weight during weight loss to help limit muscle loss. For someone who weighs 155 lbs (about 70 kg), that’s about 84 to 112 g of protein per day, though several factors including your activity level affect your protein needs.
Whole-food protein, such as lean meat, fish, eggs, and lentils, is generally preferred, since it comes with fiber and other nutrients and tends to be more filling, Kumar says. She recommends whey protein for weight loss when people struggle to get enough protein from food while cutting calories. In other words, use supplements to fill gaps rather than as your main protein source. Remember to factor the calories in protein supplements into your total intake, and choose those with little or no added sugar.
Safety and Side Effects
“These supplements and powders are typically safe,” says Rice. Though there’s one exception: People with chronic kidney disease or other kidney problems should talk with their healthcare professional before greatly increasing their protein intake. Damaged kidneys may have more trouble clearing the waste produced when the body breaks down protein.
Resources We Trust
- Cleveland Clinic: What Apple Cider Vinegar Can (and Can’t) Do for You
- Mayo Clinic: Protein Shakes: Good for Weight Loss?
- National Center for Complementary and Integrative Health: Berberine and Weight Loss: What You Need to Know
- National Institutes of Health Office of Dietary Supplements: Dietary Supplements for Weight Loss
- Harvard Health: The Hidden Dangers of Protein Powders
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
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