Appetite suppressants range from powerful prescription medications that can help you lose 15% or more of your body weight to simple dietary strategies like eating more protein or drinking water before meals. The options fall into three broad categories: prescription drugs, over-the-counter supplements, and food-based approaches. Each works differently, and the evidence behind them varies widely.
Prescription Appetite Suppressants
The most effective appetite suppressants available today are prescription medications, and most of them work by mimicking or influencing hormones that control hunger signals in the brain. These are typically prescribed for adults with obesity or those who are overweight with at least one weight-related health condition like high blood pressure or type 2 diabetes.
GLP-1 Medications
The biggest shift in appetite suppression over the past several years has been the rise of GLP-1 receptor agonists. These medications mimic a gut hormone called GLP-1 that targets areas of the brain regulating appetite and food intake. The result is that you feel full sooner and stay satisfied longer between meals. Semaglutide (sold as Wegovy for weight loss) and liraglutide (Saxenda) both fall into this category. In clinical trials, semaglutide produced roughly 13 to 14% body weight loss on average.
Tirzepatide (Zepbound) takes this approach a step further by mimicking two gut hormones instead of one, targeting both GLP-1 and a second hormone called GIP. In a head-to-head trial against semaglutide, tirzepatide produced 47% greater weight loss, with participants losing an average of 20.2% of their body weight compared to 13.7% with semaglutide.
All of these are injectable medications, typically given once a week. The most common side effects are gastrointestinal: nausea, vomiting, and diarrhea, especially when starting treatment or increasing the dose. These symptoms generally ease over time. Rare but serious risks include pancreatitis and, based on animal studies, a potential link to a type of thyroid cancer.
Combination Medications
Two FDA-approved combination pills target appetite through different pathways. Phentermine-topiramate (Qsymia) pairs a stimulant that reduces hunger with an anti-seizure medication. Together, they make you feel less hungry and fuller sooner. Naltrexone-bupropion (Contrave) combines a drug used for alcohol dependence with an antidepressant, working on brain reward circuits that influence cravings and hunger. Both are taken as daily pills rather than injections.
Phentermine Alone
Phentermine is one of the oldest prescription appetite suppressants still in use. It works as a stimulant, directly suppressing hunger signals. Unlike the medications above, phentermine is only approved for short-term use of a few weeks, not long-term weight management. It’s sometimes used as a starting point while a longer-term plan is developed.
Other Prescription Options
Orlistat (Xenical) takes a completely different approach. Rather than suppressing appetite, it blocks your gut from absorbing about a third of the fat you eat. It doesn’t reduce hunger, but it does reduce the calories your body takes in. Setmelanotide (Imcivree) is a more specialized medication that activates specific brain pathways to decrease appetite while also increasing calorie expenditure, but it’s indicated for rare genetic obesity conditions rather than general use.
Over-the-Counter Supplements
Glucomannan (Konjac Fiber)
Glucomannan is a soluble fiber derived from the konjac root. It works by forming a thick gel in your stomach, which slows digestion and creates a physical sensation of fullness. A 2020 review of six clinical trials found that glucomannan produced significant weight reduction in studies lasting more than eight weeks in overweight adults. However, other studies tell a different story. A randomized, placebo-controlled trial of 96 children found no effect on weight, and another eight-week trial in overweight adults found no significant difference between glucomannan and placebo for weight loss, body composition, or feelings of hunger and fullness.
The mixed evidence suggests glucomannan may help some people feel fuller, but it’s far from a reliable appetite suppressant on its own. If you try it, the typical approach is taking it with a full glass of water before meals.
Green Tea Extract and Caffeine
Green tea contains a compound called EGCG, which makes up about 60 to 65% of its active plant chemicals. EGCG has been shown to help reduce fat stored around organs and support healthy blood sugar levels. The caffeine in green tea stimulates the nervous system, temporarily increasing metabolic rate and promoting fat breakdown by triggering the release of adrenaline. Research suggests the two work together: caffeine alone can increase calorie burning, but pairing it with EGCG may enhance the effect. That said, the appetite-suppressing effect of green tea extract is modest compared to prescription options, and most studies show small changes rather than dramatic weight loss.
Food and Behavior-Based Approaches
Eating More Protein
Of all the non-drug strategies, increasing protein intake has some of the strongest evidence for reducing appetite. Protein suppresses ghrelin, the hormone that tells your brain you’re hungry. Studies comparing high-protein meals to high-carbohydrate meals consistently show that protein leads to greater ghrelin suppression and more favorable feelings of fullness, particularly in people with insulin resistance or type 2 diabetes. Whey protein in particular has been shown to suppress ghrelin significantly more than high-carbohydrate foods. Fat also suppresses ghrelin, but protein has the added benefit of stimulating other satiety signals as well.
In practical terms, this means meals built around protein sources like eggs, chicken, fish, Greek yogurt, or legumes tend to keep you satisfied longer than meals heavy on bread, pasta, or sugary foods. You don’t need to follow a strict high-protein diet to benefit. Simply including a meaningful portion of protein at each meal can reduce snacking and overall calorie intake.
Drinking Water Before Meals
Drinking a full glass of water before eating is one of the simplest appetite strategies, and there is some evidence it works. In one study, older adults who drank water before meals ate less than those who didn’t. Another found that people on a low-calorie diet who added water before meals experienced less appetite and more weight loss over 12 weeks than those on the same diet without extra water. The benefits are modest, though, and most of these studies have been small or short-term. No research has confirmed a long-term weight loss effect from this habit alone. Still, it’s free, has no side effects, and may help you eat a bit less at meals.
How These Options Compare
The gap between prescription medications and everything else is significant. GLP-1 drugs and tirzepatide can produce 14 to 20% body weight loss in clinical trials. Over-the-counter supplements and behavioral strategies typically produce small, sometimes undetectable effects in controlled studies. That doesn’t make the non-prescription approaches worthless, but it does mean expectations should be calibrated accordingly.
Prescription appetite suppressants also come with real tradeoffs: cost (GLP-1 medications can run over $1,000 per month without insurance), side effects, and in many cases the need to continue taking them to maintain weight loss. Non-prescription approaches carry fewer risks and can be combined freely. Eating more protein, drinking water before meals, and using fiber supplements are all compatible strategies that, layered together, may meaningfully reduce how much you eat without medication.