Do Weight Loss Pills Work?

By Craig Sorkin, DNP, APN
Medically reviewed checkmarkMedically reviewed
December 7, 2022

When it comes to losing weight, there is no shortage of fad diets, drinks, or pills, claiming they will help you reach your goal size. But do any of those “miracle pills” really work, and are they safe? 

Most diet pills say they’ll either suppress your appetite, reduce how many fats your body absorbs from your food, or increase your body’s potential to burn fat. They may be available over the counter (OTC) or by prescription. 

In this article, we discuss different diet pill options that are available, both prescription and over the counter, and whether or not they work. We also discuss the scientific evidence and if they are safe to take. 

Do Weight Loss Medications Work?

Most medical professionals agree that the healthiest way to lose weight is to eat a balanced diet and exercise regularly. Other lifestyle habits, like managing stress and getting enough sleep, can also be helpful. However, if desired, some weight loss pills can help you in your weight loss journey if you use them in combination with healthy eating behaviors and increased physical activity. 

Medications that treat obesity and aim to help with weight loss have several ways of working. For example, some pills may make you feel less hungry, while other medicines make you feel full faster. Other medications help you burn fat more easily or absorb less fat during digestion.

The best working weight loss pills contain ingredients that give you a combination of these effects. People who are pregnant or planning to be pregnant should avoid all weight loss medications as they can harm the fetus. 

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Prescription Weight Loss Pills or Injections

The Food and Drug Administration (FDA) has approved five weight-loss medications. 

Orlistat (Xenical)

This medication helps block the absorption of some of the fat you eat. As a result, it aids in weight loss or reduces the risk of gaining back weight you may have previously lost. To work correctly, take this medication with a reduced-calorie diet. 

Phentermine-topiramate (Qsymia)

This medication works to suppress your appetite. It has FDA approval for use as a seizure medication and weight loss drug. Qsymia is for use with diet and exercise. 

Naltrexone-bupropion (Contrave)

This medication works to decrease appetite, curb hunger, and reduce food cravings. Contrave works when combined with diet and exercise. 

Liraglutide (Saxenda)

Saxenda is a once-a-week injection to help with weight loss. It works as an appetite suppressant. Saxenda is for use with a healthy diet and increased physical activity.

Semaglutide (Wegovy)

Semaglutide is a medication for people with type 2 diabetes and was originally prescribed to keep their blood sugar level. Later it was FDA-approved as Wegovy to treat overweight and obesity for people experiencing medical conditions caused by excess weight. 

Wegovy is a once-a-week self-given subcutaneous injection. 

Off-label medications

“Off-label” medications are other medications that medical professionals may prescribe for weight loss. Off-label use means using the drug to treat something the FDA has not yet approved it for. Ask your medical provider if the medication they prescribe for weight loss is FDA-approved for treating overweight and obesity.

OTC Weight Loss Pills

Over-the-counter (OTC) weight loss pills are not the same as weight loss supplements. OTC weight loss drugs are FDA-approved for their effectiveness and safety, and weight loss supplements are not. The manufacturers of weight loss supplements are responsible for testing their products’ effectiveness and safety. 

Be careful when buying a diet or herbal supplement that claims to help with weight loss and understand that the FDA does not back their claims.  

Supporting Evidence 

When combined with changes to behavior, such as eating healthy and regular physical activity, weight loss pills may help some people lose weight and maintain their weight loss. Research shows that on average, people taking prescription diet pills along with participating in a lifestyle program, lose 3-12% more of their starting body weight than those participating in a lifestyle program who do not take a weight loss aid. 

Other research shows that some people lose 10% or more of their starting weight when they include prescription weight loss pills into their daily routine.

While that may not sound like a large number, losing 5-10% of your starting body weight can help improve your overall health by lowering your blood pressure, cholesterol, blood sugar, joint strain, and sleep apnea. These are great steps towards better health.

Are Weight Loss Pills Safe?

Take caution when purchasing products that claim quick and easy weight loss. Unlike prescription medications, OTC drugs and supplements are not FDA regulated or approved. 

The FDA warns of an emerging trend of OTC products, sometimes called “dietary supplements,” containing hidden active ingredients that may cause harm. They have found many products laced with prescription drug ingredients, untested pharmaceuticals, and controlled substances. See here for a full list.  

Talk to your licensed medical provider if you are considering prescription weight-loss pills. They can provide more information about safe and effective strategies for weight loss.  

Who Can Take Weight Loss Pills?

Weight loss pills may help people experiencing medical problems related to obesity or being overweight. One way that is often used to determine if you might be a candidate is to measure your body mass index (BMI).  The Centers for Disease Control and Prevention has an adult BMI calculator here.

However, the BMI is not a very accurate measure of health, as it doesn’t take into account things like fitness level, lifestyle, or muscle mass, and not everyone with a high BMI should use a weight management medication. Some may lose weight using a lifestyle program that helps them change their eating behaviors and increases their physical activity. 

Pregnant people or people trying to conceive should not take weight loss pills as they can harm the fetus. 

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When to See a Medical Provider 

Speak with your licensed medical provider if you have concerns about your weight and want guidance on the best way to lose weight and maintain a healthy lifestyle.

It’s important to note that weight loss pills can also come with side effects. For some people, they are a great weight loss tool, but they might not be for everyone. Your medical provider can help you decide the most effective and safest route. 

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Frequently Asked Questions

How much weight can you lose with pills?
Research shows that after one year, people who participate in a lifestyle program and take prescription weight loss pills lose 10% or more of their body weight. Usually, this weight loss takes place in the first six months.
What is the most effective weight loss pill?
Medical providers agree that the safest and healthiest way to lose weight is through eating healthy and exercising. However, if you need extra help with weight loss, speak with your medical provider about taking a prescription weight loss medication. They can give you further details about how the medicines work and which one would work best for you.
Do weight loss pills work?
Weight loss pills can work with lifestyle modifications such as establishing healthy eating habits and regular exercise.
Are weight loss pills safe?
Prescription weight loss pills are FDA tested and approved for effectiveness and safety. However, they do come with some possible side effects when taken. Some people hardly notice any side effects, while others may be very bothered and need to stop the medication.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Craig Sorkin, DNP, APN

Craig Sorkin, DNP, APN is a board certified Family Nurse Practitioner with over 15 years experience. He received his Undergraduate and Graduate degrees from William Paterson University and his doctoral degree from Drexel University. He has spent his career working in the Emergency Room and Primary Care. The last 6 years of his career have been dedicated to the field of digital medicine. He has created departments geared towards this specialized practice as well as written blogs and a book about the topic.

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