Can you take phentermine and Ozempic together?

In this article:

• Can you take phentermine with Ozempic?
• Benefits of taking phentermine and Ozempic together
• Risks of combining phentermine and Ozempic
• Which one is better for weight loss?
• The bottom line

In this article

• Can you take phentermine with Ozempic?
• Benefits of taking phentermine and Ozempic together
• Risks of combining phentermine and Ozempic
• Which one is better for weight loss?
• The bottom line

Phentermine and Ozempic are prescription medications that can help with weight management. While phentermine is FDA-approved for short-term weight loss when used with exercise, behavioral changes, and calorie restriction, Ozempic is prescribed off-label as a weight-loss aid. This means Ozempic is prescribed for weight loss even though it’s not approved by the FDA for that particular use. The FDA approves Ozempic to manage blood sugar levels in those with Type 2 diabetes.

While phentermine and Ozempic work through different mechanisms, they can both help with weight management. Many people wonder whether taking these drugs together can boost weight loss results. Unfortunately, the answer isn’t clear, and more research is needed to determine if combining phentermine and Ozempic is safe or effective. 

Can you take phentermine with Ozempic?

It depends. Phentermine and Ozempic aren’t known to interact with one another, and they produce weight loss in different ways. However, the use of these drugs together hasn’t been studied so it’s not known if it’s safe to combine phentermine and Ozempic.

It’s important to note that the phentermine prescribing information recommends against combining phentermine with any other weight-loss products due to the lack of evidence supporting the safety and effectiveness. The prescribing information also cautions patients about the use of phentermine with other diabetes medications, such as insulin or oral diabetes drugs. While Ozempic isn’t an insulin medication or an oral drug, healthcare providers may still be wary of prescribing Ozempic and phentermine together due to the risk of hypoglycemia (low blood sugar). 

Whether these drugs can be taken together will ultimately be up to your medical provider. They will likely take into account your current medications, medical conditions, and the severity of your condition before deciding whether it’s safe for you to take Ozempic and phentermine together. 

Benefits of taking phentermine and Ozempic together

Phentermine works as an anorectic, which means it’s an appetite suppressant. It does this by releasing chemicals in the brain that help regulate appetite. When taken alone, studies found phentermine can result in weight reduction of 5% to 10% over 14 weeks when used with a lower-calorie diet and increased exercise. According to the drug’s prescribing label, weight loss is typically the greatest in the first few weeks of treatment and then decreases in succeeding weeks. 

While Ozempic isn’t FDA-approved for weight management, its active ingredient–semaglutide–has been well-studied for weight loss. Semaglutide operates as a glucagon-like peptide-1 (GLP-1) receptor agonist. It promotes weight loss by slowing the emptying of the stomach, signaling fullness to the brain, lessening feelings of hunger, and increasing the body’s insulin production. Evidence shows people who use semaglutide once weekly may experience weight loss of almost 6% after 3 months. 

With each drug working differently to promote weight loss, many may consider combining their use to enhance weight loss results. However, there are no studies to date focusing on the use of phentermine and Ozempic together. It’s best to discuss their use with a healthcare provider. They can discuss the potential benefits and risks of combining phentermine and Ozempic. 

Risks of combining phentermine and Ozempic

Because phentermine and Ozempic haven’t been studied together, the risks of this combination are unknown. Nevertheless, phentermine and Ozempic each have their own potential risks, including side effects, drug interactions, and contraindications. 

Side effects

Both drugs have potential side effects that range from mild to serious. The following table outlines some of the common side effects of phentermine and Ozempic.

Drug	Mild side effects	Serious side effects
Phentermine	Restlessness Dizziness Trouble sleeping Tremor (shakiness) Headache Dry mouth Unpleasant taste Diarrhea Constipation Skin rash Changes in sex drive	Primary pulmonary hypertension (high blood pressure in the lungs) Valvular heart disease Heart palpitations Fast heart rate High blood pressure psychosis  Erectile dysfunction
Ozempic (semaglutide)	Nausea Vomiting Diarrhea Abdominal pain Constipation Burping Flatulence Gastroesophageal reflux disease (GERD) Gastritis	Thyroid cancer* Kidney problems Pancreatitis Gallbladder problems Allergic reactions

* Ozempic (semaglutide) has a boxed warning for the risk of thyroid cancer. 

Traditionally, phentermine has had a risky reputation in part because it’s chemically similar to amphetamine medications and other stimulant drugs. According to the drug’s prescribing information, there is a possibility of abuse of phentermine, and because of this risk, the drug is classified as a controlled substance and is typically prescribed at the lowest effective dose for the shortest amount of time needed.

Drug interactions

Ozempic and phentermine both have potential drug interactions as well. Ozempic can interact with medications that lower blood sugar levels, such as insulins or sulfonylureas. While Ozempic alone doesn’t cause hypoglycemia, combining Ozempic with these drugs can increase the risk of hypoglycemia from insulin or other drugs. Examples of insulins and sulfonylureas may include:

• Micronase (glyburide)
• Glucotrol XL (glipizide)
• Amaryl (glimepiride)

Because Ozempic works by slowing the emptying of the stomach, it may interact with certain oral drugs by increasing how long the drug stays in the stomach. The longer drugs stay in the stomach, the more time your body can absorb the drug. This can lead to a larger amount of the drug in your system, which increases your risk of side effects. Synthroid (levothyroxine) is an example of a drug that can interact with Ozempic through this mechanism. 

Phentermine can interact with several drugs, many of which are mental health medications such as selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs), and certain antipsychotics. These interactions can cause serotonin syndrome, high blood pressure, or seizures. It’s also well-known that phentermine may interact with blood pressure medications, as phentermine can counteract the effects of blood pressure-lowering drugs. 

Contraindications

Healthcare providers typically won’t prescribe Ozempic or phentermine for people with certain health conditions or health factors. These conditions or factors are referred to as contraindications. For example, because of Ozempic’s boxed warning for thyroid cancer, the drug is contraindicated for people with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Additionally, Ozempic should not be used by people who’ve had an allergic reaction to semaglutide or any of its ingredients. 

Phentermine should not be taken by people with the following conditions:

• History of heart problems, such as coronary artery disease, stroke, arrhythmias, heart failure, or uncontrolled high blood pressure
• Hyperthyroidism
• Glaucoma
• History of drug abuse
• Agitation
• Pregnancy or breastfeeding
• Allergic reaction to phentermine or a similar drug

Because of the risk of severely high blood pressure, phentermine is also contraindicated in those who take or have taken MAOIs within the last 14 days. 

Which one is better for weight loss?

There haven’t been any head-to-head studies comparing Ozempic and phentermine for weight loss. In most cases, phentermine is only prescribed for short-term use for up to 12 weeks. However, there may be some instances where a healthcare professional may recommend it for longer. Semaglutide–the active ingredient in Ozempic–is typically prescribed for long-term use.

According to the drug’s prescribing information, the amount of weight you may lose while taking phentermine varies from study to study. In a 2021 clinical trial of over 900 adults, about 80% of people with obesity lost 5% of their body weight after taking phentermine for 6 months. In a small study from 2006, more than 50% of people lost at least 10% of their body weight after 14 weeks of phentermine treatment. 

On the other hand, people can lose almost 6% of their body weight after three months of semaglutide treatment. And the average weight loss for overweight or obese people is nearly 15% after 68 weeks of semaglutide treatment.

Although choosing between Ozempic and phentermine may depend on your weight loss goals, it’s important to also consider the safety of each drug before determining which is the best option for you. 

The bottom line

On paper, it may seem safe to take Ozempic and phentermine together. The drugs aren’t known to interact with one another, and they work differently to produce weight loss. However, the use of these drugs together hasn’t been studied so it’s not known if it’s safe or effective to use them in combination. 

Because of the potential risks of each drug, it’s important to consult your healthcare provider before starting treatment with either or both drugs. Your provider will likely consider your medical history, current medication list, and other health factors to help determine if these drugs are right for you. They can also discuss the potential risks and benefits of combining Ozempic and phentermine.