Popular Weight Loss Drugs

Weight Loss Medications: An Overview

If you are ready to lose weight, diet and exercise can help you to get rid of unwanted pounds.

However, weight loss medications are available that claim to make it easier or quicker to get the results you desire. In this article, we will look at the most popular weight management medications to help you decide which drug could best suit you and your lifestyle.

What are overweight and obesity?

Overweight and obese are two terms that are often used informally to refer to being heavy or large. According to the World Health Organization (WHO), in both conditions, there is the excessive fat accumulation that presents a risk to health.

The Body Mass Index value (a measure of weight compared to height) is used to define both being overweight and obese.

  • A BMI of over 25 is considered overweight
  • A BMI of over 30 is categorized as obese ( 1 ).

Between 2017 and 2018 in the USA, 42.4% of adults were obese. This increased from 30.5% between 1999 and 2000.

Having a BMI above 25 is sadly associated with chronic diseases, including heart disease, stroke, and diabetes. Being diabetic increases the risk of kidney damage, amputations, and sight loss.

It is therefore important to try to achieve a healthy weight for your height. Some people decide to achieve this with the help of weight loss medications.

How do weight management medications work?

Weight loss pills work in conjunction with a variety of biological processes to help you lose weight. Some medications, such as beta-glucans, contain natural soluble fibers that increase feelings of fullness to discourage overeating.

Caffeine, another weight loss ingredient found in many medications, works by increasing fat oxidation. Greater consumption of coffee has been associated with a lower risk of obesity ( 3 ).

Phentermine, marketed as Adipex P, stimulates the secretion of noradrenaline, therefore suppressing the appetite. Used safely for over 40 years in the US, its low side effect profile has allowed it to remain a popular choice for weight loss ( 4 ).

The newest weight loss medication to be approved by the FDA (The US Food and Drug Administration), Wegovy, works by mimicking GLP-1, a hormone that regulates the appetite. Taking this latest medication may help to reduce food intake, leading to weight loss.

What are the benefits of using prescription medications to lose weight?

Benefits of prescription weight loss medications

Losing weight by dieting or through exercise or physical activity requires determination and long-lasting willpower.

Experts have found that when medications approved for long-term obesity treatment are used in addition to lifestyle alterations, the likelihood of achieving clinically meaningful weight loss within one year is increased. Furthermore, the mean weight loss during this time tends to be greater ( 6 ).

A study in 2021 found that those who took weight loss medications were more likely to lose ≥5% of their initial weight than with a placebo. Weight loss ranged from 3.4kg to 8.9kg, depending on the drug ( 7 ).

What are the concerns about using prescription medications to lose weight?

A prescription weight loss medication should only be taken after careful consideration of its pros and cons.

As with all prescription medications, it is not unusual for a drug to cause mild, unwanted symptoms in some people. However, in the past, some weight loss medications have been linked to serious side effects that have caused harm.

Despite initial clinical testing, treatments have been approved and then later discontinued when the risk of side effects outweighed the potential benefit of weight loss. Serious adverse effects have included an increased risk of cancer, heart attacks, and stroke ( 8 , 9 ).

It is important to understand the risks of any medication you are prescribed or purchase over the counter. It is reassuring to note that older weight loss medications, such as phentermine, have been used extensively and are therefore considered to be safe when used as directed.

However, as side effects may still occur in some people, it is important only to take a medication that a doctor has prescribed for you. If your BMI is under 25, pharmacological treatment to aid weight loss is inappropriate.

Currently available weight loss medication

With many options available, starting your research can be a daunting task. You may be interested in learning about each medication in more detail. Alternatively, the table below offers a summary of prescription medications that are approved by the FDA to treat those who are overweight or obese.

What is the best weight loss medication?

It is important to keep your weight within a healthy range to avoid obesity-related medical complications, so finding an effective treatment is crucial.

The best weight loss medication is one that offers clinically significant weight loss without the risk of serious side effects. 

It is difficult to say which weight loss drug will best suit your individual requirements.

However, your doctor is well-placed to discuss any options based on your weight and any medical history of note. Choosing an extensively studied medication such as phentermine may reassure you of the drug’s safety and likely efficacy.


Who might benefit from weight management medications?

It is common to look for additional support in losing weight when dieting or increased physical activity alone has not led to the desired results. Weight loss medication is usually only prescribed for those with a BMI of over 25, but it is important to check the manufacturer’s recommendation for each product.

Can medications replace physical activity and healthy eating habits?

For best results, medication for weight loss should be taken alongside a healthy diet and regular exercise. This will not only help you to lose weight faster but will also improve your cardiovascular health.

How long will I need to take weight management medication?

Some prescribed medications are only approved by the FDA for 12 weeks, while others can continue providing weight loss is sustained. Orlistat, for example, can be taken for a year or more if weight loss continues but should be stopped after 12 weeks if <5% of body weight has been lost. 

You should, therefore, be prepared to take the medication for at least 12 weeks to review its efficacy.

Will I regain some weight after I stop taking weight management medication?

To keep your weight stable after stopping your medication, it is vital that you continue to eat healthily and take part in intense physical activity several times a week. If you return to overeating or a sedentary lifestyle, weight regain is likely.

Will insurance cover the cost of weight management medication?

Some insurers may cover the cost of your medications. You should speak to your provider for more information.

What are the differences between OTC and prescription weight loss medications?

Prescription weight loss medications are approved by the FDA (The US Food and Drug Administration) to treat weight loss. This means that they are proven to be safe, and effective, and have benefits that outweigh any risks. Over-the-counter medications may not have been approved by the FDA for weight loss, and the claims of what the product can do may not have been verified.

What is the connection between antidepressant medication and weight loss?

Many antidepressants cause weight gain, but bupropion, one of the drugs in Contrave, can cause weight loss. Bupropion alters the levels of chemicals in the brain to lift the mood. Another effect of the altered chemicals is reduced appetite, and, therefore weight loss.


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