Phentermine alternatives: What can I take instead of phentermine?

Compare phentermine alternatives | Contrave | Lomaira | Mounjaro | Saxenda | Wegovy | Natural alternatives | How to switch meds

Phentermine is a prescription drug used along with diet and exercise for the short-term (several weeks) treatment of obesity in adults. Phentermine may be prescribed in patients with an initial body mass index (BMI) of 30 kg/m2 or more—or patients with a BMI of 27 kg/m2 who also have other risk factors such as high blood pressure, diabetes, or high cholesterol. 

Phentermine, first approved by the U.S. Food and Drug Administration (FDA) in 1959, is available as an oral tablet and capsule. Phentermine is usually dispensed as a generic drug but is also commonly referred to by its brand name, Adipex-P.

Phentermine is part of a drug class called sympathomimetic amine anorectics. Phentermine works by decreasing the appetite (an appetite suppressant) which helps in reducing food cravings and increasing your metabolic rate to aid in fat loss. To do so, phentermine stimulates the neurotransmitters in the central nervous system to suppress feelings of hunger. It is a Schedule IV controlled substance. This means it has the potential for abuse and dependence. Phentermine is chemically related to the ADHD drug amphetamine and other central nervous system (CNS) drugs that are often abused. Because of this, healthcare professionals will weigh the risk of abuse before prescribing phentermine as a weight loss pill. When phentermine is prescribed, its monthly supply is generally prescribed in small amounts to lessen the risk of an overdose.

Sometimes, an individual may seek a different treatment than phentermine. Some patients may not see the desired effects of phentermine and may want to seek the best alternative to see if a different drug is more effective. Or, because phentermine is only approved as a short-term treatment, certain patients may want to seek the best phentermine alternatives that can be used for more extended periods of time.

Others may experience side effects that are bothersome or do not go away. Some of the common adverse effects of the prescription phentermine include:

• Heart palpitations
• Fast heart rate
• Increased blood pressure
• Restlessness 
• Trouble sleeping
• Dizziness 
• Euphoria (feeling intensely excited and happy)
• Dysphoria (feeling uneasy, unhappy, or unwell)
• Tremor
• Headache 
• Dry mouth 
• Unpleasant taste in the mouth
• Constipation or diarrhea
• Hives
• Sexual problems such as impotence (difficulty achieving or maintaining an erection) or changes in libido

In some cases, a serious side effect may occur. Severe side effects may include blocked blood flow to the heart, fast heart rate, hypertension (high blood pressure), or pulmonary hypertension (high blood pressure in the lungs). 

Some individuals cannot take phentermine at all. Individuals with a history of substance use disorder may not be appropriate candidates for phentermine. Other individuals that should not take phentermine include:

• People with an allergy to phentermine, amphetamine, or any CNS stimulant drug
• People who have taken a drug in the monoamine oxidase inhibitor (MAOI) class of drugs within the past 14 days
• Women who are pregnant or breastfeeding
• People with severe kidney problems or on dialysis
• People with certain blood vessel or heart conditions (or a history of heart conditions)
• People with high blood pressure that is not controlled by medication
• People with hyperthyroidism (overactive thyroid)
• People with glaucoma
• People in an agitated state

For patients seeking an effective phentermine alternative, there are other medications for weight loss that can be discussed with a healthcare professional. 

What can I take in place of phentermine?

If you are looking for a phentermine alternative, other types of medications are available. The table below compares phentermine (in bold) with common alternatives. All of the weight loss drugs listed are FDA-approved prescription medications. One of these options may be more suitable for certain individuals due to different side effect profiles or dosing schedules.

Other alternatives to phentermine

• Alli (orlistat OTC)
• Benzphetamine
• Diethylpropion extended-release
• Evekeo (amphetamine)
• Ozempic (semaglutide): as an off-label use
• Phendimetrazine 
• Phendimetrazine extended-release
• Victoza (liraglutide): as an off-label use
• Xenical (orlistat Rx) 

Top 5 phentermine alternatives

The following are some of the most common alternatives to phentermine.

1. Contrave (naltrexone and bupropion) oral tablet

Contrave contains two ingredients. Naltrexone, an opioid antagonist, and bupropion, an antidepressant, work on two areas of the brain that are involved in the appetite and reward system. While phentermine is approved for short term-use, Contrave is used for long-term treatment. Contrave should be used along with a healthy diet and exercise. It can be used in adults with a BMI of 30 kg/m2—or adults with a BMI of 27 kg/m2 or more with at least one weight-related risk factor such as high blood pressure, high cholesterol, or Type 2 diabetes. 

Common side effects include nausea, constipation, diarrhea, headache, vomiting, dizziness, trouble sleeping, and dry mouth. 

Contrave has a black box warning, the strongest warning required by the FDA. The black box warning is due to the antidepressant ingredient in Contrave, bupropion. Patients who take Contrave should be closely monitored for changes in mood and behavior or suicidal thoughts and behaviors. Contrave should never be used in children or adolescents under 18 years old. 

RELATED: Compare Contrave vs. phentermine

2. Lomaira (phentermine) oral tablet

Lomaira is a brand-name drug that contains phentermine, but in an 8 mg dose—a smaller dose that is taken three times daily—rather than the typical generic phentermine dose, which is generally a larger dose taken once daily. Lomaira is only available under the brand name. There is no equivalent generic 8 mg phentermine. Like phentermine, Lomaira is approved for the short-term treatment of obesity in combination with diet and exercise. 

Common side effects of Lomaira are the same as generic phentermine in larger doses and include heart palpitations, fast heart rate, increased blood pressure, dizziness, trouble sleeping, euphoria, dysphoria, headache, dry mouth, stomach problems, hives, and sexual problems.

3. Mounjaro (tirzepatide) injection 

Mounjaro is currently approved for adults with Type 2 diabetes—combined with diet and exercise, Mounjaro helps control blood sugar levels. Currently, many healthcare professionals prescribe Mounjaro off-label for weight loss. Off-label prescribing is when a drug is prescribed for a use not approved by the FDA. 

In a study called the SURMOUNT-1 trial, Mounjaro was found to help participants lose a significant amount of weight. In October 2022, the FDA gave Mounjaro a Fast Track designation to be studied for weight loss. A Fast Track designation means that the medication review and approval process will occur faster than usual to fulfill an unmet medical need. 

Mounjaro, taken as a once-weekly injection, is classified as a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist. While other injectable drugs approved for Type 2 diabetes or weight loss are GLP-1 receptor agonists, Mounjaro is the first GIP and GLP-1 receptor agonist.

Common side effects include appetite loss as well as stomach problems such as nausea, vomiting, diarrhea or constipation, indigestion, and stomach pain. 

Because Mounjaro affects stomach emptying, women who take oral contraceptives (birth control pills) should use a barrier method of birth control (such as condoms) or another form of effective birth control for 4 weeks after starting Mounjaro, and for 4 weeks after every dose increase. Women can discuss effective forms of birth control with their healthcare provider.

Mounjaro has a black box warning. The warning, which applies to any drug that contains a GLP-1 agonist, states that the drug causes thyroid C-cell tumors in rats. However, it is not known if Mounjaro can cause thyroid cancers in humans. Mounjaro should not be used in people with a history (or family history) of medullary thyroid carcinoma or in people with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Individuals who take Mounjaro should be alert to symptoms of thyroid tumors (such as a lump in the neck, hoarseness, shortness of breath, or trouble swallowing) to their healthcare provider right away. 

4. Saxenda (liraglutide) injection

Saxenda is a GLP-1 receptor agonist that contains the ingredient liraglutide. It is approved for long-term weight management in combination with diet and exercise in adults with a BMI of 30 kg/m2—or adults with a BMI of 27 kg/m2 or more with at least one weight-related risk factor. It can also be used in adolescents 12 years and older who weigh more than 60 kg (132 lbs) and have an initial BMI corresponding to 30 kg/m2 in adults. 

Common side effects of Saxenda include stomach problems, including nausea, vomiting, diarrhea or constipation, indigestion, stomach pain, and stomach virus. Other common side effects may include injection site reactions, headache, tiredness, dizziness, and fever. Hypoglycemia (low blood sugar) may occur in patients with Type 2 diabetes who also use insulin or certain diabetes medications. 

Because Saxenda affects stomach emptying, ask your healthcare provider when you should time any oral medications.

Saxenda has the same black box warning as Mounjaro and should not be used in people with a history or family history of thyroid cancers. Patients who take Saxenda should be alert to symptoms of thyroid cancer.

5. Wegovy (semaglutide) injection

Wegovy is another GLP-1 agonist and is one of the newer drugs approved for weight loss. Wegovy contains the ingredient semaglutide. Wegovy is a weekly injection that is FDA-approved for long-term weight management (in combination with diet and exercise) in adults with a BMI of 30 kg/m2—or adults with a BMI of 27 kg/m2 or more with at least one weight-related risk factor. 

Common side effects include stomach problems such as nausea, vomiting, diarrhea or constipation, stomach pain, bloating, indigestion, gas, burping, reflux, and stomach virus. Other common Wegovy side effects may include low blood sugar (especially in those with Type 2 diabetes who use insulin or certain diabetes medicines), headache, fatigue, and dizziness.

Like Saxenda, Wegovy affects stomach emptying. Ask your healthcare provider when you should time any oral medications.

Wegovy has the same black box warning as Mounjaro and Saxenda regarding thyroid tumors. 

Natural alternatives to phentermine

Many patients ask about natural alternatives to phentermine. The natural alternative aisle is filled with diet pills and weight loss supplements touting weight loss benefits and money-back guarantees. Ingredients like green coffee bean extract, green tea extract, guarana, vitamin b6, and cayenne pepper may sound harmless. However, long-term studies of natural supplements conclude that even though they are made with natural ingredients, these supplements are not likely to contribute to significant weight loss—and in some cases, may harm the patient. Be cautious when supplement labels claim to boost energy, boost metabolism, and increase fat burning and energy levels to stop weight gain and fat production. These assertions are likely unfounded and do not mean that they are natural phentermine alternatives or phentermine substitutes. Don’t be fooled. Approved over-the-counter phentermine alternatives and phentermine alternative supplements do not exist.

Also, supplements are not held to the same standards as high-quality prescription medications. The Dietary Supplement Health and Education Act (DSHEA) assigns responsibility to dietary supplement companies to ensure safety standards. The FDA does not have the authority to approve supplements for safety and efficacy before they are sold to the public. If you are considering taking a supplement to help with weight loss, consult your healthcare provider. However, prescription weight loss medications are not studied in combination with supplements, so you should not use a supplement in combination with a prescription weight loss medication—unless advised by your healthcare professional. 

Consult your healthcare provider about dietary changes and exercise. A registered dietician can be an excellent resource on your weight loss journey in helping you devise a personalized eating plan that considers your nutritional needs, calorie intake, medical conditions, and lifestyle. Diets are not a one-size-fits-all approach. The best eating plan is one that is healthy, with a variety of nutritious foods, and is something you can stick to for the long term. 

Regarding exercise, adults should aim for at least 150 minutes of moderate-intensity activity per week to help decrease body fat, plus two days of muscle-strengthening activity to help build and maintain muscle mass. One way to attain the 150 minutes is to walk for 30 minutes a day, 5 days a week. A gym is not necessary—you can walk outside or choose from thousands of free YouTube videos—there are even free indoor walking videos online. Just check with your healthcare provider first, if there are any limitations on physical activity, before selecting an exercise plan. 

How to switch to a phentermine alternative

When considering a switch to a phentermine alternative:

• Check your formulary, or ask your healthcare provider to check your formulary, to see which phentermine alternatives your health insurance plan covers. You can also search the SingleCare website or mobile app for free coupons. SingleCare customers can save up to 80% on prescription prices—what’s more, you can use SingleCare savings every time you fill your prescription.
• Consult your healthcare provider. Your healthcare provider is the only one who can determine which medication is best for you, considering your medical and family history, medical conditions, and medications you take that may potentially interact with weight-loss medications. You can also talk about dietary changes and exercise and ask for a referral to a registered dietician.
• Once the new prescription is sent to the pharmacy, speak with your pharmacist. Review dosing instructions and potential side effects, and ask any questions you may have. If you get an injectable drug, be sure you understand how and when to use it. 
• When at home, read the prescription label, patient information leaflets, and/or medication guides. If anything concerns you or if you have questions, consult your healthcare provider or pharmacist.