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Which Diet Pills Have Been Approved by the FDA?

Which Diet Pills Have Been Approved by the FDA?

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    Despite what all of those constant spam emails and ads tell you, there is no “one simple trick” or magic diet pill that’ll help you drop the pounds overnight. However, a few well-studied medications are shown to help increase your chances of weight loss success.

    As of July 2022, there are seven different medications approved by the U.S. Food and Drug Administration for long-term weight loss support, meaning you can take them for longer than 12 weeks:

    • Contrave (Bupropion-naltrexone)
    • Saxenda (Liraglutide)
    • Xenical (Orlistat)
    • Qsymia (Phentermine-topiramate)
    • Imcivree (Setmelanotide)
    • Plenity (Superabsorbent Hydrogel Particles in Capsules)
    • Wegovy (Semaglutide)

    In addition, five other weight-loss drugs have FDA approval for short-term use (12 weeks or less):

    • Phentermine
    • Benzphetamine
    • Diethylpropion
    • Phendimetrazine

    Each of these prescription medications works by cutting cravings and/or making you feel fuller faster, but all come with potential side effects like insomnia, constipation, a higher heart rate, and an increased chance of addiction.

    Longer-term weight loss medications with FDA approval still pose side effects but don’t pose as many risks for addiction.


    Contrave is an adult-only weight loss pill combination for those with a body mass index (BMI) of at least 30 or adults with a BMI of 27 or above who have a weight-related condition such as high blood pressure, type 2 diabetes, heart disease, or high cholesterol.

    How It Works

    Contrave is a combination of two prescription drugs used to treat addiction and obesity. The first drug, naltrexone, has been used to treat alcohol and opioid addiction, and it blocks the brain’s receptors for these substances, reducing cravings. The second drug, bupropion, is an antidepressant that can help people quit smoking. It works by increasing levels of dopamine and norepinephrine, two brain chemicals linked to feelings of well-being.

    How to Use

    Contrave comes in tablet form, and you increase the number you take over a few weeks. During the first week, you take one tablet in the morning or evening alongside a high-fat meal, increasing to one tablet in the morning and once at night during the second week.

    Your dose increases to two tablets in the morning, once at night during week three, and two tablets in the morning and at night in week four and beyond.

    Expected Weight Loss

    There is no guarantee that you will lose weight while taking Contrave, but if you do lose weight, it’ll take about four weeks to start seeing results.

    Clinical trials have shown that people who take Contrave for a year can lose about 11 percent to 12 percent of their body weight. This weight loss is in addition to any weight loss you may experience from lifestyle changes, such as eating a healthier diet and exercising more.

    You’ll take Contrave for 12 weeks before returning to your doctor. If you haven’t lost at least five percent of your weight, then it’s unlikely you’ll lose weight with more treatment.

    Potential Risks and Side Effects

    The most common side effects of Contrave include nausea, constipation, headache, and dizziness. These side effects usually disappear after the first week or two of treatment.

    Contrave can cause serious side effects, including an increased risk of suicidal thoughts or actions, mood issues, and seizures. It can also cause increased blood pressure, heart rate, and blood sugar levels. People with a history of eating disorders such as bulimia or anorexia nervosa should not take Contrave, as it can worsen these conditions.


    closeup of liraglutide pills

    Saxenda is a prescription medication approved for use in adults with a BMI of 30 or higher and children and teens aged 12 to 17 years with a BMI of at least 27. Saxenda is also approved for use in adults with a BMI of 27 or higher who have at least one weight-related health condition, like type 2 diabetes, high cholesterol, or high blood pressure.

    How It Works

    Saxenda works as a weight loss pill by making you feel fuller (AKA increases satiety) and reducing your hunger.

    The active ingredient is liraglutide, a type of GLP-1 receptor agonist. GLP-1 receptor agonists are drugs that mimic the effects of GLP-1, a hormone that is released after we eat. GLP-1 signals the body to release insulin and reduce appetite.

    How to Use

    Saxenda comes in a pre-filled pen that you use to inject yourself once a day whenever it’s convenient — and you can take it with or without food. Following instructions on how to use the pen is essential, as an improper injection can lead to side effects.

    You’ll likely start Saxenda treatment by injecting 0.6 mg. After that, your doctor may increase your dose by 0.6 mg until you get to a 3 mg daily dose.

    Expected Weight Loss

    Like other FDA-approved weight-loss drugs, Saxenda isn’t guaranteed to make you lose weight, and you should combine it with a healthy diet and exercise.

    That said, multiple studies show that people going through Saxenda treatment do lose weight. In one study, adolescents who used Sanexa lost almost three percent of their body weight — a five percent greater loss than those in the control group. The same study showed that adults had an average weight loss of eight percent.

    Other studies on those with type 2 diabetes lost anywhere from five to eight percent of weight loss compared to the placebo groups.

    Don’t expect to see that weight loss immediately, though: It’ll be at least two weeks of treatment before you start noticing any weight loss.

    Potential Risks and Drawbacks

    Like all medications, Saxenda comes with potential risks and drawbacks, including:

    • Hypoglycemia (low blood sugar)
    • Nausea
    • Vomiting
    • Diarrhea
    • Constipation
    • Headaches
    • Dizziness

    In rare cases, Saxenda can also cause pancreatitis (pancreas inflammation).

    You shouldn’t use it if you use any other medication containing liraglutide or are allergic to any ingredients.


    box of xenical capsules on counter

    Xenical — also sold over-the-counter as alli — is a prescription medication containing the active ingredient orlistat that is used to help people lose weight by preventing the body from absorbing some of the fat from food. It’s usually prescribed for people with a BMI of 30 or over and isn’t recommended for children.

    How It Works

    Xenical works by inhibiting gastric and pancreatic lipases, enzymes that break down fats in the intestine. This action allows for reduced absorption of calories from fat, which can lead to weight loss. Xenical is typically used with a low-fat, reduced-calorie diet and exercise program to help promote weight loss.

    How to Use

    Xenical comes in pill form and is typically taken three times per day. The recommended dose of Xenical is one 120 mg capsule taken with water immediately before, during, or up to one hour after each main meal — and skip it if you miss a meal.

    Expected Weight Loss

    Unlike other types of FDA-approved weight loss medications, the effects of Xenical can be seen as soon as 24 hours after dosing. The downside? The effects stop when you stop taking the medication.

    That said, Xenical can help promote weight loss when used in conjunction with a low-fat, reduced-calorie diet. In clinical studies, people taking Xenical lost an average of 6.2 percent of their body weight, while those not taking the drug lost an average of 5.8 percent.

    It is important to note that weight loss is not the only goal when taking Xenical. Reducing the amount of fat absorbed by the body can also help prevent weight regain and reduce the risk of developing obesity-related conditions such as type 2 diabetes and heart disease.

    Potential Risks and Drawbacks

    It’s wise to be close to a bathroom until you know how Xenical will affect you because common side effects include:

    • Oily stools
    • Oily spotting on underwear or clothing
    • Orange or brown colored oil in stool
    • Anal and fecal leakage
    • Gas with discharge, oily discharge
    • Diarrhea
    • Abdominal pain
    • Headache
    • Back pain
    • Flu-like symptoms

    More severe side effects include jaundice, pancreatitis, gallstones, and increased liver enzyme levels.

    Xenical should not be used in people allergic to orlistat or who have problems absorbing food. Pregnant or breastfeeding women should not use Xenical.


    Qsymia is a once-a-day combination medication that may help control cravings. It’s only for adults with obesity (a BMI of 30 or higher) or a BMI of at least 27 with at least one weight-related condition like type 2 diabetes, high blood pressure, or high cholesterol.  

    How It Works

    Like Contrave, Qsymia combines two medications — in this case, phentermine and topiramate ER to help with weight management.

    Phentermine is a sympathomimetic amine that is an appetite suppressant and is sometimes prescribed as a short-term weight-loss drug. It works by stimulating the release of norepinephrine, a neurotransmitter that helps to regulate mood and energy levels. Norepinephrine also helps reduce hunger signals, leading to reduced food intake and weight loss.

    Topiramate is primarily an anti-epileptic medication, also known as an anticonvulsant. One of the mechanisms by which topiramate is thought to help with weight loss is by reducing hunger and cravings, and this can lead to eating fewer calories overall, promoting weight loss.

    Additionally, topiramate may help you feel fuller after eating, so you won’t eat as much. It is also thought that topiramate may help to boost metabolism and fat burning, although more research is needed in this area.

    How to Use

    Qsymia is available in tablet form and should be taken orally, with or without food, once a day. It’ll work best if you follow a healthy diet and exercise routine.

    Expected Weight Loss

    Weight loss results with Qsymia vary from person to person and are, of course, not guaranteed.

    That said, In one clinical trial, study participants who took Qsymia experienced a 6.7 kg greater weight loss than those on the placebo treatment.

    Potential Risks and Drawbacks

    The most common side effects of Qsymia include:

    • Nausea
    • vomiting
    • constipation
    • diarrhea
    • headache
    • dizziness
    • Insomnia

    Also, drinking alcohol can increase adverse side effects, so don’t use alcohol while on a Qsymia regimen.

    See Also
    avocado, broccoli and vegetables on counter


    Approved by the FDA in late 2020, Imcivree is a weight-loss medication for people ages six or over with obesity related to three rare genetic conditions:

    • Pro-opiomelanocortin (POMC) deficiency
    • Proprotein subtilisin/Kexin type 1 (PCSK1) deficiency
    • Leptin receptor (LEPR) deficiency

    These conditions can cause obesity at a very young age and affect their metabolisms, hunger levels, and ability to feel full.

    Imcivree is sometimes “off-label” for other purposes, such as weight management treatment in people with obesity alongside other medical conditions.

    How It Works

    Imcivree works by activating areas of the brain that regulate appetite and fullness.

    This causes patients with specific defects in these brain areas not to eat as much, leading to weight loss. Imcivree also increases resting metabolism, the number of calories the body burns at rest, and increasing resting metabolism can help contribute to weight loss.

    Expected Weight Loss

    Eighty-six percent of children ages six to 17 experienced a significant BMI reduction after using Imcivree. Adults ages 18 or older experienced an average body weight loss of 10 percent.

    Potential Risks and Drawbacks

    Potential side effects and risks of using Imcivree include:

    • Nausea
    • Vomiting
    • Diarrhea
    • Stomach pain
    • Decreased appetite
    • Weight loss
    • Dizziness
    • Tiredness
    • Dry mouth

    Rare — but serious — side effects of Imcivree can include:

    • Severe allergic reactions (rash, hives, itching, difficulty breathing, chest tightness, or swelling of the mouth, face, lips, throat, or tongue),
    • Heart rate or blood pressure changes
    • Hallucinations
    • Psychosis
    • Seizures


    Plenity is a non-invasive weight loss pill designed to help people lose weight by reducing hunger. Plenity is made of two natural fiber ingredients, cellulose, and glucomannan, which are known to reduce hunger and promote fullness.

    How It Works

    Plenity is a prescription medication that helps you lose weight by reducing hunger and making you feel full. Plenity works by absorbing water in the stomach, which expands and makes you feel full. This leads to reduced appetite and fewer cravings and can help you eat less at each meal.

    How to Use

    Plenity is taken in three capsules with 16 ounces (two glasses) of water 20 minutes before lunch and dinner.

    Expected Weight Loss

    There is no guarantee that you will lose weight while taking Plenity, but in a study, participants who took the pill lost an average of five percent of their body weight after 12 weeks compared to those who did not.

    Potential Risks and Drawbacks

    Plenity is safe and well-tolerated but does have the potential for mild effects. Most common include headaches, nausea, and constipation; less common side effects include dizziness, diarrhea, and stomach pain.


    Wegovy is an injectable weight-loss medication for adults with a BMI of 30 or over or those with a BMI of at least 27 with at least one weight-related health issue like high blood pressure, cardiovascular disease, and cholesterol.

    How It Works

    Wegovy works by mimicking a hormone called glucagon-like peptide-1 (GLP-1) that targets areas of the brain that regulate appetite and food intake. When GLP-1 is released after a meal, it tells the brain to stop eating.

    How to Use

    Unlike most weight-loss medications approved by the FDA, you only need to take Wegovy once per week via injection with a one-time-use pen.  

    A starting dose is typically 0.25 mg once per week for four weeks, then increasing to higher doses every four weeks until reaching a 2.4 mg dose once per week.

    Expected Weight Loss

    Wegovy starts working immediately after injecting, but it’ll take several weeks to start noticing effects and weight loss.

    While weight loss is never promised by simply using a medication, several studies have shown that Wegovy can help with significant weight loss. One study conducted over 104 weeks found that treatment helped reduce body weight by 15.2 percent vs. 2.6 percent in the placebo group.

    Another study showed that those who took Wegovy lost as much as 15 percent of their body weight, though most lost 10 percent.

    Potential Risks and Drawbacks

    The most commonly reported side effects of Wegovy treatment include bloating or pain in the stomach, gas, indigestion, fatigue, nausea, and constipation.

    Some of the more severe side effects include gallbladder issues, as well as an increased heart rate and pancreatitis. It’s also important to note that Wegovy has a boxed warning for its risk of thyroid cancer.

    Disclaimer: The information on this website is for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare providers with any questions you may have regarding a medical condition or treatment before undertaking a new healthcare regimen.
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