The most effective options for weight loss range from prescription medications that can help you lose 15% to 21% of your body weight, down to over-the-counter supplements with far more modest effects. What makes sense for you depends on how much weight you need to lose, whether you qualify for a prescription, and what you’re willing to spend. Here’s a clear breakdown of what’s available and what the evidence actually shows for each.
Prescription Medications: The Strongest Options
If you have a BMI of 30 or higher, or a BMI of 27 with a weight-related health condition like type 2 diabetes or high blood pressure, you may qualify for a prescription weight loss medication. These are the only options backed by large clinical trials showing significant, sustained weight loss.
GLP-1 and GIP Receptor Agonists
The newest and most effective class of weight loss drugs works by mimicking gut hormones that regulate appetite and blood sugar. These are injectable medications you take once a week.
Semaglutide (Wegovy) helped adults with obesity lose roughly 18% to 21% of their body weight over about 72 weeks in clinical trials. Tirzepatide (Zepbound) targets two gut hormone receptors instead of one and has shown comparable or slightly better results. Most people notice meaningful changes within the first two to three months, commonly losing around 10 pounds in that early window before the effects compound over time.
The trade-off is gastrointestinal side effects. About 1 in 5 semaglutide users experience nausea, and roughly 1 in 4 tirzepatide users do. Diarrhea affects about 11% of semaglutide users and 15% of tirzepatide users. Vomiting occurs in about 9% for both. These side effects tend to be worst during dose increases and often improve over time. Both medications are started at low doses and gradually increased to help your body adjust.
Oral Prescription Options
Not everyone wants or can afford an injectable. Several oral prescription medications are also FDA-approved for weight management, though they produce less dramatic results than the newer injectables.
Phentermine-topiramate (Qsymia) combines two drugs: one triggers the release of norepinephrine, a brain chemical that suppresses appetite, while the other was originally developed for epilepsy and migraines but also reduces food cravings. It’s one of the more effective oral options.
Naltrexone-bupropion (Contrave) pairs an opioid-blocking compound with a drug that increases dopamine and norepinephrine activity. The combination works on reward pathways in the brain, which can help reduce food cravings, particularly emotional or compulsive eating. Weight loss is typically more modest than with GLP-1 drugs.
Liraglutide (Saxenda) is an older GLP-1 drug that requires daily injections rather than weekly ones. It’s effective but has largely been overshadowed by the newer weekly options.
The One Over-the-Counter Drug
Orlistat is the only FDA-approved weight loss medication available without a prescription, sold under the brand name Alli at a lower dose. It works differently from everything else on this list: instead of suppressing appetite, it blocks your body from absorbing about 30% of the fat you eat. That unabsorbed fat passes through your digestive system and is excreted.
This mechanism works, but it comes with a catch. Eating a high-fat meal while taking orlistat can cause oily stools, gas, and urgent bowel movements. Many people find these side effects motivating in a roundabout way, since they encourage sticking to a lower-fat diet. The weight loss is modest compared to prescription-strength options, typically a few extra pounds over several months beyond what diet alone would achieve.
Supplements With Some Evidence
The supplement aisle is full of products promising easy weight loss. Most have little or no clinical evidence behind them. A few have shown real but small effects in studies.
Green tea extract, which contains caffeine and a compound called EGCG, increased 24-hour energy expenditure by about 4% compared to placebo in a controlled study. That’s a real metabolic boost, but a modest one. It might translate to a few extra calories burned per day, not a dramatic transformation on its own.
Glucomannan, a soluble fiber derived from konjac root, expands in your stomach and can help you feel full before meals. A meta-analysis of randomized controlled trials found it produced a statistically significant weight reduction of about 1 kilogram (roughly 2 pounds) compared to placebo. That’s a real effect, but a small one, and results varied widely between studies.
Berberine, a plant compound that’s gained attention on social media as “nature’s Ozempic,” has shown legitimate effects on blood sugar and insulin sensitivity. In a clinical trial comparing it to metformin in people with prediabetes, berberine performed comparably at lowering fasting blood sugar over 12 weeks. However, improving blood sugar control and losing weight are different outcomes, and the evidence for berberine as a direct weight loss tool is limited. It may help if insulin resistance is contributing to your weight, but calling it a substitute for GLP-1 drugs is a stretch.
Protein as a Weight Loss Tool
This one isn’t a pill or supplement in the traditional sense, but increasing your protein intake is one of the most consistently supported dietary strategies for weight loss. Protein has a higher thermic effect than carbohydrates or fat, meaning your body burns more calories digesting it. It also keeps you full longer, which naturally reduces how much you eat at the next meal.
You can get this benefit from food (chicken, fish, eggs, legumes) or from protein powders like whey or casein if you find it hard to hit higher protein targets through meals alone. The goal isn’t to add calories on top of what you’re already eating but to shift your diet so a larger proportion of calories comes from protein. Most research on satiety and body composition supports aiming for roughly 25 to 30 grams of protein per meal.
How to Think About Your Options
The gap between prescription medications and supplements is enormous. GLP-1 drugs can help you lose 15% to 21% of your body weight. Green tea extract might bump your metabolism by 4%. Glucomannan might help you lose an extra 2 pounds. These aren’t in the same category, and it’s worth being honest about that when deciding where to put your money and effort.
If you have a significant amount of weight to lose and qualify medically, prescription options offer the most reliable path. If you’re looking to lose a smaller amount, or you want to complement other efforts like dietary changes and exercise, protein intake and fiber supplements can provide a genuine edge. What rarely works is buying a bottle of capsules from a health food store and expecting dramatic results without changing anything else. The compounds that move the needle the most all require either a prescription or a real shift in how you eat.