Ozempic vs. Phentermine: The ultimate weight loss comparison The image shows an Ozempic injectable pen and Phentermine pills.

Ozempic vs. Phentermine: The ultimate weight loss comparison

April 3. 2023

There are many different ways to achieve weight loss goals. For those who decide to go with a medical program, the options keep increasing every year as new drugs are discovered. Today, we want to discuss Ozempic vs. Phentermine – two prescription weight-loss medications that, with their efficacy, make it difficult for people to decide which program to start.

Currently, there are seven FDA-approved weight loss drugs on the market for public use. Choosing the right weight loss therapy will guarantee your success but also that you feel comfortable during the extent of the treatment. Each patient has different goals and needs, so finding the most suitable plan is crucial. For that, you have to be aware of the options that are out there and which ones top the list in efficiency, safety, and speed. Because when you want to achieve substantial weight loss, you probably want to see results as fast as possible. But sustainability is also important. So besides speed, you must aim for a treatment that promises long-term results. And that is what takes most people to debate between Ozempic vs. Phentermine. Both weight loss medications have all the benefits we just mentioned. However, there could be one that better suits your weight loss journey.

Do you want to find out which weight loss program will take you to your goals faster? Continue reading; our weight loss clinic in Chicago experts share their knowledge on Phentermine and Ozempic in this article.

How does Ozempic work for weight loss?

Let’s start by clarifying that Ozempic is a type 2 diabetes medication; it is not included on the FDA-approved weight loss medications list. However, Ozempic’s active ingredient, semaglutide, is on that list but under the brand name Wegovy. The same pharmaceutical company, Novo Nordisk, manufactures both drugs; Ozempic for treating diabetes in adults and Wegovy for weight loss management. Both medications have the same active compound; therefore, they help with weight loss in the same way.

Ozempic weight loss works by mimicking a receptor agonist called glucagon-like peptide-1 (GLP-1). It is a naturally occurring hormone that is present in the human body in small quantities, and it doesn’t last long in our system. Semaglutide imitates the effects of this gut hormone. After eating, GLP-1 stimulates the pancreas to increase insulin secretion and indicates the liver to lower glucagon secretion. In people with type 2 diabetes, that helps them reduce blood sugar levels and avoid hyperglycemia.

During Ozempic clinical trials, the studies showed that the effects of semaglutide also have weight loss benefits. Those benefits were tested in other clinical trials to prove whether Ozempic was effective for weight loss management. The results were positive; people with and without diabetes lost a significant amount of weight when using Ozempic – paired with diet and exercise.

The increase in insulin and decrease in glucagon secretion slows down how quickly food you eat leaves your stomach (gastric emptying). When this happens, you feel less hungry during the day and also more satisfied after having a meal. Even with a light, low-calorie email, you will feel like you have had enough.

Phentermine: The Go-To Appetite Suppressant

As the heading suggests, Phentermine for weight loss has been the go-to appetitive suppressant for several decades. The Food and Drugs Administration approved Phentermine-topiramate, most commonly known as Phentermine, back in 1959. It makes Phentermine the oldest prescription drug approved for weight management. With so many decades on the market and its weight loss efficacy, there is no doubt that this medication has so many patient success stories.

Phentermine-topiramate belongs to a drug group called anorectics. This medication’s main role is to induce appetitive suppression. It is a stimulant, which means it works directly on the central nervous system in our brains. Simply put, Phentermine increases the levels of three neurotransmitters in our brains (dopamine, serotonin, and norepinephrine). Once the levels of these chemical transmitters are high, you will feel less hunger and fewer food cravings.

A healthcare provider can prescribe Phentermine for you if you struggle with obesity. The bodies of obese individuals often have a hard time regulating hormone levels, including hunger hormones. Their brains also struggle to process or respond normally to these hormones. That is why after having a proper meal, some people still feel hungry, and sticking to a healthy diet can be extra challenging. Phentermine weight loss can come to the rescue when that is the case. The chemical messages this appetite suppressant drug stimulates will let the brain know you are full after you have a meal. This effect, combined with a Phentermine diet plan, will help you limit how many calories you consume daily. And this will eventually take you to lose body weight and achieve your weight loss goals.

Ozempic vs. Phentermine: Main differences

Now that we explained the basics of each medication and how they work for weight loss, we can move on to the main topic of this article: Ozempic vs. Phentermine. So far, it is clear that both prescription weight-loss medicines have appetite suppression benefits. In other words, Phentermine and Ozempic cause the same effect – they decrease hunger – but they do so in very different ways.

Even with all that information, deciding which weight loss program suits you best can still be challenging. Let’s dive deeper into the main difference so you can make a well-informed choice when picking between Ozempic and Phentermine.

Who is eligible for these weight management drugs?

To qualify for any of these two weight loss drugs, you’ll need a body-mass index of 30 or higher. You are also eligible for Phentermine or Ozempic if you have a body-mass index of 27 and a weight-related condition, such as diabetes, high blood pressure, or heart disease. Does any of those two options describe your current condition? Then you can resort to one of these medications to achieve rapid weight loss. And, at the same time, improve your health and life quality.

If, on the other hand, you do not meet those requirements, another weight loss program may be more suitable for you. You can discuss your situation and the most suitable treatment with your healthcare provider. Some people resort to a healthy meal plan and fasting. The fasting benefits by hour go beyond weight loss, and this practice can help you reach your goals fast.

Professionals advise you not to start taking any of these medications if you are pregnant or planning to have a baby. There are not enough studies on Ozempic and pregnant women to determine how this drug could affect the fetus. Phentermine and pregnancy is also not a good combination; studies do not show any issues if you were on Phentermine during the first trimester of your pregnancy. However, as soon as you find out you are pregnant, your doctors will advise you to quit the medicine until after you deliver the baby.

Dosage and how to use the medication

Both medications differ significantly in this aspect. Phentermine is a short-term medication; typically, you take this drug for about 12 weeks. After that time, you have to stop using Phentermine; also, the body tends to adapt to the medication, so its appetite-suppressing effect decreases or stops. You take Phentermine orally – in the form of tablets, disintegrated tablets, capsules, or extended-release capsules. The dosages and how many times a day you take it will depend on the strength of the medication and your particular situation and goals. Often, you take Phentermine early in the morning, a few hours before you have breakfast; you take the medication every day.

Ozempic is a long-term medication; the extent of the treatment will depend on your starting weight and your desired goal. This drug comes in injectable pens; you must apply the weight loss drug injections once a week, every time on the same day of the week. At the beginning of the program, you will start with a minimal dosage of 0.25 mg a week. After a month, your doctor can increase the dosage to another 0.25 mg, and so on, until you reach the maximum allowed dose of 2 mg per week. Most patients ask us how long does Ozempic take to work? But there is no definite answer. It will depend on how fast your body adapts to the medication and how long it takes you to reach a high dose.

Which medicine is more effective for weight loss?

Both medicines are viral because of their weight loss efficacy. While there could be one that suits you better, you will likely achieve weight loss with any of them.

With Phentermine, patients often lose an average of 5% of their body weight during the 12 weeks of treatment. Ozempic clinical trials showed an average weight loss of 5% with the maximum dose. However, some patients reach up to 10%. That number is achieved when the program is combined with a low-calorie diet and exercise. Some people also include fasting into the mix to achieve faster weight loss; combining Ozempic and coffee has also been shown to improve the effectiveness of this medication.

What are the side effects of each drug?

The secondary adverse effects are another aspect most patients consider when choosing a medical weight loss treatment. Like most drugs, these medications also can potentially cause some side effects, so the Ozempic vs. Phentermine debate can not miss this point.

Phentermine’s most common side effects include chest pain, insomnia, dry mouth, constipation, diarrhea, headaches, and dizziness. Some severe and rare side effects of this medication are high blood pressure in the lungs (pulmonary hypertension) and heart valve disease.

Regarding Ozempic, the common side effects are nausea, vomiting, abdominal pain, diarrhea, and constipation. And the more severe but rare side effects include pancreatitis, change in vision, low blood sugar (hypoglycemia), kidney problems, and gallbladder disease.

You also must keep in mind that these medications can interact with other drugs or substances. For instance, combining Ozempic or Phentermine and alcohol is highly discouraged.

Can you take Ozempic and Phentermine at the same time?

We used this article to open the discussion about Ozempic vs. Phentermine. But could the focus change to Ozempic and Phentermine? As you already know, both medications will help you feel less hungry and achieve weight loss through a low-calorie meal plan. But could these two drugs help each other to boost your weight loss journey?

Ozempic is proven to provide more significant weight loss than Phentermine. Still, typically, it takes about eight weeks for individuals to start seeing results with Ozempic. Are you not losing weight on Ozempic during the initial weeks? While that is normal, it can also be discouraging. A good idea could be to kick-start the treatment with extra aid from Phentermine.

Currently, there are no studies about how Ozempic and Phentermine work together. You must first consult with your healthcare provider if you are thinking about trying both at the same time.

Final thoughts

Now you know every important detail about two of the most efficient weight loss medications; you can choose which one suits you better and start your weight loss journey. However, if instead of Ozempic vs. Phentermine, you want to boost your weight loss efforts by resorting to both drugs simultaneously, you can schedule a call with us. Our team of experienced healthcare professionals can assess your situation and, after a careful medical examination, let you know if the Ozempic and Phentermine combination is the right way to go.

Nurse Walton


Nurse Walton

Born and raised in Chicago, IL, Chanay received her Practical Nurse licensure and went to work in clinical specialties such as Home Health, Assisted Living, Long-Term Care and Dialysis Centers. Through this work, she realized the importance of diet, nutrition and weight loss among her patients. This led her to open A Better Weigh, Inc. Medical Weight Loss Center in 2009.

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