Do Prescription Weight Loss Pills Actually Work?

If you’ve tried diet and exercise but you’re still struggling to lose weight, you might consider prescription weight-loss medication. Diet pills have a bad reputation as people abused them in the past, but when they’re used responsibly with healthy diet and exercise habits, they can give you a weight-loss boost

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How do weight loss pills work?

There is a range of weight-loss pills available that use various techniques to help you lose weight. Typically, they tend to work in two ways:

  • Reducing your body’s ability to absorb fat from the food you consume

  • Suppressing your appetite, so you eat less

These medications are only available through prescription, with options for short-term and long-term use. So, what pills help you lose weight? Let’s look at prescription medications that can aid in weight loss. 

Diet medications and how they work


Phendimetrazine increases your heart rate and reduces your appetite. Typically only used short-term, you take this medication within an hour before meals to reduce your food intake and aid weight loss¹.


Orlistat is a long-term medication that reduces your calorie intake by blocking fat absorption from food. You use Orlistat in conjunction with a reduced-calorie and low-fat diet to lose weight².


Liraglutide is typically used as an anti-diabetic medication, but it also has positive effects on weight loss. Research has found it helps people with obesity lose weight and keep it off as it reduces hunger and increases feelings of fullness³. 


Benzphetamine medication can help you lose weight in the short term. It reduces your appetite and slightly increases your metabolism when you take it with a reduced-calorie diet and regular exercise⁴. 

Who can take prescription weight-loss pills?

Doctors typically prescribe weight-loss pills to people who can’t lose weight effectively through traditional methods like diet and exercise. But you do need to be in a high-need category to be considered for a prescription.

If you’ve tried to lose weight but haven’t reached your goal, you might be considered for weight-loss medication if:

  • Your BMI is 30 or higher

  • Your BMI is 27 or higher, and you have obesity-related health conditions

  • After six months of regular diet and exercise, you haven’t been able to lose one pound per week⁵

BMI is a measure of your body mass index. You can calculate your BMI by comparing your weight to your height, and calculators like this one⁶ make it easy. It is important to remember that a high BMI doesn’t necessarily mean that you need to lose weight. For instance, short people with large amounts of muscle will often have a high BMI. Ask your doctor about your BMI before making any decisions about weight loss.

With around 70% of American adults struggling with their weight, weight-loss medications can offer a real health boost. Losing 5-10% of body weight can reduce your risk of cardiovascular disease⁵ and other illnesses.

Are weight loss prescriptions safe?

Prescribed weight-loss medications offer a safe and effective way to help people lose weight. However, these medications can cause side effects like nausea and diarrhea. It’s important to discuss the benefits and side effects of the medication with your doctor, and they will help you decide whether weight-loss medication is the right fit for you.

On the whole, prescribed weight-loss medications offer significant health benefits, improving blood pressure, heart health, blood sugar levels, and the overall quality of life.

There has been some controversy with prescription weight-loss medications. For example, Fen-Phen was a combination medicine using fenfluramine and phentermine that the FDA (Food and Drug Administration) banned due to links to heart valve disorders⁷. Because of this, doctors treat weight-loss medication with care.

You should be especially wary of over-the-counter weight-loss pills. They are not regulated and don’t require FDA approval. They can contain some potentially very dangerous ingredients, especially if you take these pills alongside other medications.

Unsafe ingredients, including herbs like ephedra, have been found in these unregulated weight-loss supplements. The FDA banned ephedra after studies discovered side effects like strokes, heart attacks, and seizures⁸.

What is the best prescription weight loss pill?

The right weight-loss pill for you will depend on how you react to it, your personal needs, and any other medications you might be taking. Your doctor will be able to help you determine which is best for you. Weight-loss medication is not a cure-all: You also need to make diet and lifestyle modifications for it to work effectively.

Whether you need short-term medication to kick-start weight loss or something longer-term to keep weight off, there are many options to discuss with your doctor. 

The lowdown

If you're struggling to lose weight, prescription weight-loss pills can improve your heart health, mood, blood pressure, and quality of life.

Weight-loss pills aren’t for everyone, and they can have side effects to consider. But with proper medical consultation, these medications can be effective and safe for patients with high BMIs who want to lose weight.

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