The most effective options for weight loss are prescription medications, which now include both pills and injections that can help people lose 5% to 17% of their body weight depending on the drug. Over-the-counter supplements exist but have far less evidence behind them. What you can take depends on your body mass index, your health history, and whether you qualify for a prescription.
Who Qualifies for Prescription Weight Loss Drugs
Doctors can prescribe weight loss medication if you have a BMI of 30 or greater, or a BMI of 27 or greater with a weight-related condition like high blood pressure or type 2 diabetes. These thresholds come from federal guidelines and apply across all the major prescription options. If you fall below these cutoffs, prescription medications generally aren’t available to you, and lifestyle changes or supplements are the typical starting point.
GLP-1 Medications
GLP-1 drugs are the biggest development in weight loss treatment in decades. They work by mimicking a gut hormone that slows digestion, increases feelings of fullness, and suppresses appetite. The result is that you naturally eat less without the same level of hunger you’d normally experience.
Wegovy (semaglutide) is the most well-known, originally available only as a weekly injection. In January 2025, the FDA approved an oral pill version containing the same active ingredient. The pill uses a special coating that protects it from being broken down by stomach acid. Semaglutide typically produces weight loss in the range of 10% to 15% of body weight over about a year.
Foundayo (orforglipron), a daily pill from Eli Lilly approved in April 2026, works through the same pathway but uses a different type of compound that’s less likely to break down during digestion. Unlike Lilly’s injectable drug tirzepatide (Zepbound), which targets two appetite-related hormones, Foundayo targets only one.
The most common side effects of GLP-1 drugs are nausea, vomiting, diarrhea, and loss of appetite. These tend to be worst when you first start the medication or move to a higher dose, and they often improve over time. Rare but serious risks include pancreatitis, thyroid cancer, sudden kidney injury, and worsening of diabetes-related eye disease.
These medications are intended for long-term use. The World Health Organization’s 2025 guideline supports ongoing treatment, though it notes that data on what happens after people stop taking them is still limited. Most people regain a significant portion of lost weight after discontinuing GLP-1 drugs, which is why many providers treat obesity as a chronic condition requiring sustained therapy.
Other Prescription Options
GLP-1 medications aren’t the only prescription route. Several older drugs remain available and can be effective, particularly when combined with diet changes and exercise.
Phentermine/topiramate (Qsymia) is a combination pill that suppresses appetite through the nervous system. It produces the highest percentage of weight loss among the older options. In clinical trials lasting about two years, participants on the higher dose lost an average of 10.5% of their body weight. It requires regular monitoring of blood pressure, heart rate, and mood.
Naltrexone/bupropion (Contrave) works on brain pathways that regulate appetite and cravings. It produced about 6% weight loss over a year in trials, and up to 9.3% when combined with structured behavior modification. This drug is sometimes chosen for people who also deal with food cravings or emotional eating patterns.
Orlistat (Xenical, or the lower-dose over-the-counter version Alli) takes a completely different approach. Instead of acting on appetite, it blocks your body from absorbing about a third of the fat you eat. That unabsorbed fat passes through your digestive system, which is why the main side effects are oily stools, gas, and urgency. In trials, orlistat users lost about 10% of body weight over a year compared to 6% with placebo.
What Prescription Drugs Cost
Cost has been one of the biggest barriers to weight loss medication. Without insurance or discount programs, Wegovy runs about $1,350 per month and Zepbound about $1,086 per month. A government pricing initiative called TrumpRx has negotiated these down to roughly $350 per month for injectable versions. Oral GLP-1 drugs, if purchased through the same program, are priced at $150 per month for the initial dose.
Insurance coverage varies widely. Some plans cover weight loss medications, especially if you have a qualifying condition like diabetes. Others exclude them entirely. Manufacturer savings programs and compounding pharmacies offer alternative paths, but coverage remains inconsistent.
Over-the-Counter Supplements
The supplement aisle is packed with products claiming to help with weight loss. The evidence behind most of them is thin.
Caffeine is the best-studied ingredient. It increases your metabolic rate and fat burning modestly. A 100 mg dose (roughly one cup of coffee) increases energy expenditure by about 9 extra calories per hour for three hours or more. That adds up to very little on its own, but caffeine is safe for most adults at doses under 400 mg per day. Higher doses can cause jitteriness, rapid heartbeat, and nausea.
Green tea extract gets a lot of attention. A large review of 14 clinical trials found it reduced body weight by an average of about 2 pounds more than placebo. But when researchers looked only at studies conducted outside Japan, the effect disappeared entirely, suggesting the benefit may depend on genetics or diet patterns. Green tea extract also carries a small risk of liver damage, so drinking green tea as a beverage is generally safer than taking concentrated supplements.
Glucomannan is a fiber supplement that expands in your stomach to make you feel full. Despite the logical mechanism, clinical data shows it has little to no actual effect on body weight. Tablet forms can also pose a choking risk if they expand before reaching the stomach.
No over-the-counter supplement comes close to the 5% to 17% weight loss seen with prescription medications. If supplements appeal to you, caffeine through coffee or tea is the most reasonable option, but the effect is modest at best.
What Your Doctor Will Monitor
Weight loss medications aren’t a “take and forget” treatment. Regardless of which drug you’re prescribed, your provider will track your weight, blood pressure, heart rate, blood sugar, and mood at regular intervals. Some medications require additional checks: kidney function for GLP-1 drugs, liver function for naltrexone/bupropion, and thyroid checks for liraglutide. If you haven’t lost at least 5% of your body weight after three to six months on a given medication, your doctor will typically reassess whether to adjust the dose, switch drugs, or try a different approach.
Combining Approaches
Clinical trials consistently show that medication works best alongside dietary changes and physical activity. In one study, naltrexone/bupropion combined with structured behavior modification produced 9.3% weight loss, compared to 6.1% with the drug alone. This pattern holds across most weight loss drugs: the medication reduces hunger or absorption, but the habits you build around eating and movement determine how much benefit you actually get.
For people who don’t qualify for prescription drugs or prefer not to take them, the combination of a modest calorie reduction (around 500 calories per day below maintenance) and regular exercise remains the foundation. It typically produces 1 to 2 pounds of loss per week, which is slower than medication but sustainable for many people without the side effects or cost.