Wegovy vs Phentermine for Weight Loss: Which is Better?

It is a well-known fact that obesity can increase the risk of serious health problems, including diabetes, high blood pressure, and other cardiovascular diseases. If weight loss efforts with a healthy diet and exercise have not helped you lose weight, prescription weight loss therapy may be an option. That’s why anti-obesity medications have become very popular due to their ability to promote weight loss, consequently lowering the risk of chronic disease.

Please continue reading to learn more about two commonly prescribed weight loss medications — Wegovy and phentermine. Besides comparing Wegovy and phentermine, we will also list the pros and cons of including these medications in your weight loss journey.

What is Wegovy?

Wegovy is the brand name of the generic medication semaglutide. Semaglutide was originally developed as an injectable prescription medication for people with type-2 diabetes. It belongs to a group called glucagon-like peptide-1 (GLP-1) receptor agonists. These medications mimic the action of a hormone called GLP-1 and promote insulin secretion in the human body, thereby reducing blood glucose levels.

While Wegovy is approved to be used as a weight loss drug, Ozempic, containing the same active compound, semaglutide, is indicated to treat type-2 diabetes only.

As mentioned, Wegovy is FDA-approved for treating obesity. This medication helps the body to produce more insulin, and by signaling fullness, this medication helps reduce appetite and, therefore, results in weight loss. Wegovy is used to achieve weight loss along with a reduced-calorie diet and regular exercise in individuals who meet one of the following criteria:

Adults with a body mass index (BMI) of 30 or higher;
Adults with a BMI of 27 or higher who have a weight-related health condition;
Children aged 12 and higher with a BMI in the 95th percentile, which is classified as being obese

Wegov is started at a low dose (0.25 milligrams) weekly and gradually increased to a higher dose based on your response, with a maximum dose of 2.4 mg weekly.

What is phentermine?

Phentermine is an anorectic (weight loss drug) that acts on the central nervous system and decreases appetite. It helps with weight loss in people who eat a healthy, low-calorie diet and get regular exercise. This weight loss medication is approved for people 17 years of age and older. Most people take phentermine for only a few weeks, depending on how they respond to the treatment.

The FDA also approved Qsymia, the combination of phentermine and topiramate extended-release capsule, for chronic weight management in children aged 12 and older.

Which is better for weight loss: semaglutide or phentermine?

Both phentermine and semaglutide are effective weight loss drugs that can help you lose weight if you eat a low-calorie diet and participate in an exercise program. One of these weight loss medications may be better for you than the other. Your healthcare provider will help you choose. The key differences between Wegovy vs phentermine are as follows:

FDA approval

Phentermine hydrochloride (sold under brand names Adipex-P, Suprenza, and Lomaira) is one of the oldest FDA-approved weight loss drugs on the market. It was originally approved by the FDA in 1959.

Wegovy (active ingredient: semaglutide) is one of the newest weight-loss medications on the market. Even though Wegovy was used previously to treat type-2 diabetes and heart disease, It was approved as a weight loss drug in 2021.

Method of administration

Phentermine comes in the form of oral tablets to be taken by mouth once daily.

Wegovy is a subcutaneous injection that is given under the skin once a week. It comes as an easy-to-use pen for self-administration that contains a fixed dose of the medicine.

Age range

Phentermine is approved for people 17 years and older. Wegovy is approved for people 12 years of age and older.

Duration of treatment

Phentermine is usually prescribed for 3-6 weeks. Your doctor may prescribe it for longer periods, up to 12 weeks, depending on how you respond to it. They may also prescribe phentermine intermittently to prevent weight regain.

Wegovy is intended for long-term use. If you tolerate the medication without side effects and it helps you lose weight, you can continue taking it for chronic weight management along with diet and exercise.

Average weight loss

How much weight you can lose on weight loss medication depends on many factors, including your starting weight, your body’s response, and lifestyle changes. However, the good news is that both Wegovy and phentermine show encouraging results in helping people to lose weight.

More head-to-head clinical trials comparing Wegovy and phentermine are necessary to establish their roles in chronic weight loss management. Notably, clinical trials have shown that Wegovy has a more significant weight loss compared to other weight management like phentermine.

Specifically, a retrospective study has shown that weight loss achieved with Wegovy was about 6.7 kilograms (kg) at 3 months and 12.3 kg at 6 months.

Again, the best weight loss medication and weight loss program is one that is effective and safe for you. There are many approved weight loss medications available currently. You should discuss with your healthcare provider about the benefits and risks of these treatments prior to incorporating it into your weight loss regimen.

Side effects

Common side effects of phentermine include an unpleasant taste, dry mouth, nausea, vomiting, diarrhea, constipation, and bloating.

Common side effects of Wegovy include heartburn, burping, stomach pain, nausea, vomiting, diarrhea, constipation, and low blood sugar.

Warnings

Phentermine may not be right for people with hypertension (high blood pressure). This drug has been linked to serious health complications such as primary pulmonary hypertension and valvular heart disease. In addition, phentermine is a schedule IV (four) controlled substance, meaning this medication carries the risk of misuse. However, the rate of misuse and dependence seems to be low.

Wegovy carries a boxed warning about the potential risk of thyroid tumors. This medication is not for people who have a personal or family history of medullary thyroid cancer or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

What is better than phentermine for weight loss?

Several medications are available for losing weight. Your healthcare provider will help you choose the best prescription drug for weight management. Possible phentermine alternatives include:

Semaglutide (Wegovy)
Liraglutide (Saxenda)
Naltrexone and bupropion (Contrave)
Diethylpropion (Tenuate)
Phentermine topiramate (Qsymia)
Orlistat (Alli, Xenical)

Your healthcare professional will help you choose between phentermine, Wegovy, and other drugs, depending on your weight loss goals, underlying health problems, and other factors. If you are severely obese, you should discuss bariatric surgery (weight loss surgery) as an option for significant weight loss and long-term weight management.

What is the strongest weight loss prescription pill?

Phentermine is known for its ability to help you achieve rapid weight loss with short-term use. However, you may experience weight gain when you stop taking the medication. On the other hand, a weight loss medication such as Wegovy can be used for long-term weight management. Even though there are not a lot of studies comparing Wegovy and phentermine directly, there is data that shows that Wegovy can lead to more weight loss compared to other weight loss medications like phentermine.

Can I take Wegovy and phentermine together?

Wegovy and phentermine work in different ways and do not interact. So, theoretically, you can take them together and potentially lose even more weight. However, healthcare professionals avoid prescribing them at the same time because they haven’t been studied for safety and efficacy when taken together.

What new weight loss drug is better than Wegovy?

There are a few new drugs on the horizon that are currently undergoing clinical trials and that may prove to be better than Wegovy — only time will tell. Three drugs that may get FDA approval in the near future include tirzepatide (Mounjaro), orflorglipron, and retatrutide. Oral semaglutide may also become available.

What are the pros and cons of taking medications for chronic weight management?

When obese or overweight people take weight loss medicine along with lifestyle modifications, they can achieve greater weight loss than lifestyle modifications alone. Taking weight loss medications can decrease hunger and result in a significant amount of weight loss, typically ranging between 5-15% for most patients. This may not seem like a lot, but losing just 5-10% of your body weight can lower your risk of many serious health conditions.

However, like most medications, both Wegovy and phentermine can cause side effects. Some of these side effects are mild and go away once your body gets used to the medication. However, rarely, these drugs can cause serious side effects. Your health care provider will discuss the treatment choices with you, including the risks versus benefits of the two medications - phentermine vs Wegovy - as well as other weight loss drugs.

Another thing to keep in mind is that certain weight loss drugs, especially the newer agents, can be expensive and may not be covered by insurance.

Last but not least, many people regain some of the lost weight when they stop taking weight loss medications. Healthy lifestyle habits are key to keeping the weight off.

Do I qualify for weight loss medications to lose weight?

You may qualify for a weight loss drug if you have been unable to lose weight with diet and exercise alone and you have a body mass index (BMI) of greater than 30 or a BMI of greater than 27 and a serious chronic disease linked to obesity, such as diabetes or high blood pressure.

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