Phentermine vs Contrave for Weight Loss: Which Works Best?

Phentermine and Contrave are two of the most commonly prescribed weight loss drugs in the U.S. While they work in different ways, both have helped many individuals lose weight when combined with lifestyle changes. If you’re trying to decide between these two medications, it’s important to understand how they work, who they’re best suited for, and what risks may be involved.

In this guide, we’ll break down everything you need to know about phentermine vs Contrave, including their benefits, possible side effects, drug interactions, and real-world effectiveness.

Key Takeaways

• Phentermine works as a short-term appetite suppressant affecting the central nervous system, while Contrave combines two medications—naltrexone and bupropion—for a longer-term approach to weight management.
• Both medications can lead to meaningful weight loss, but they come with different risks, side effects, and contraindications, especially for people with heart disease or high blood pressure.
• Choosing the best weight loss medication depends on your individual health history, goals, and tolerance for adverse reactions. Always consult a healthcare professional before starting any prescription weight loss medication.

Understanding Phentermine

Phentermine is an FDA-approved weight loss pill used for short-term treatment of obesity. It works by stimulating the central nervous system to suppress appetite, similar to how amphetamines work. Because of this, phentermine is classified as a controlled substance and is typically used for a few weeks at a time.

Phentermine helps compatible patients lose weight by decreasing hunger, which can make it easier to stick to a reduced-calorie diet and increase physical activity.

“Phentermine remains one of the most widely prescribed prescription drugs for weight loss, particularly for patients looking for a fast start to their weight management journey,” says Dr. Matthew Olesiak, MD, Chief Medical Director at SANE MD.

Pros of Phentermine

• Fast-acting appetite control
• Widely available as a generic prescription drug
• Can help initiate weight reduction in certain individuals who are considered overweight

Cons of Phentermine

• Risk of psychological dependence
• May cause trouble sleeping, dry mouth, or high blood pressure. See our complete guide for side effects and safety tips for Phentermine usage.
• Not recommended for people with existing heart disease

How Contrave Works

Contrave is an FDA-approved brand-name medication that contains two active ingredients: naltrexone (an opioid antagonist) and bupropion (used to treat depression and aid in smoking cessation). Together, these two medications work on different areas of the brain to regulate hunger and cravings.

The extended-release tablet must be taken consistently, often beginning with one oral tablet per day and increasing to a full Contrave dosage of two tablets twice daily.

“The unique mechanism of Contrave makes it particularly helpful for patients who struggle with emotional eating or food addiction,” explains Dr. Olesiak. “By addressing reward pathways in the brain, it targets not just appetite but also behavior.”

How Contrave Affects the Brain

Contrave influences both the hypothalamus (controlling hunger) and the mesolimbic reward system (controlling cravings), making it especially effective for patients who overeat due to emotional stress.

Taking Contrave: What to Know

Patients typically start by taking one Contrave tablet in the morning. Over the course of four weeks, they gradually increase to the maintenance dosage. Avoiding a high-fat meal when taking Contrave is essential, as it increases the risk of seizures.

Contrave is not a controlled substance, but it still carries warnings for serious side effects, including suicidal thoughts, allergic reactions, and seizures, especially in young adults and those taking other medications for mental health.

Common Side Effects of Contrave:

• Dry mouth
• Nausea or constipation
• Suicidal thoughts or self-harm in rare cases
• Headaches and dizziness
• Adverse effects when taken with alcohol or after abruptly stopping alcohol

Comparing Phentermine vs Contrave

Feature	Phentermine	Contrave
Mechanism	Appetite suppressant	Opioid antagonist + antidepressant
Form	Oral tablet	Extended-release tablet
Usage	Short-term treatment	Long-term treatment
Side Effects	Dry mouth, insomnia, anxiety	Nausea, headache, dry mouth
Controlled Substance	Yes	No
Works On	Central nervous system	Brain reward system & hunger center
Insurance Coverage	Sometimes limited	Often covered
Maintenance Dosage	Varies by patient	Two tablets twice daily

Both phentermine and Contrave treatments support weight management, but the best choice depends on individual goals and risk factors.

Which One Leads to More Weight Loss?

When comparing phentermine vs Contrave for effectiveness, both medications have shown success in helping compatible patients lose weight and reduce body weight. However, the degree and sustainability of that weight loss can differ depending on several factors, including duration of use, patient adherence, and lifestyle changes such as diet and exercise.

In clinical studies, such as one published in Endocrine Practice, phentermine users typically experienced more rapid weight reduction in the first few weeks of treatment. This is largely due to phentermine’s stimulant effect on the central nervous system, which quickly suppresses appetite. For individuals needing immediate help to control portions or reduce snacking, this can be a motivating start. That said, phentermine is only approved for short-term treatment, usually not exceeding 12 weeks, due to concerns about heart disease, high blood pressure, and psychological dependence. Still…it’s evident that Phentermine works for weight loss.

On the other hand, Contrave is designed for long-term treatment and may produce more consistent weight loss over time. Unlike phentermine, Contrave does not rely solely on appetite suppression. Instead, it targets brain pathways associated with both hunger and reward—an approach that may be particularly useful for individuals who tend to eat in response to emotional triggers. Many patients see sustained weight loss over several months of consistent use, especially when combined with a balanced diet and increased physical activity.

Several head-to-head trials suggest that while phentermine can lead to a higher percentage of body weight lost in the early phases of treatment, Contrave may edge ahead in terms of total weight loss after six months or more of continuous use. Contrave’s longer treatment window also allows for more comprehensive behavior modification strategies to take root, improving the chances of lasting weight management. Long-term studies of Phentermine are limited, as it is designed to be taken for just a few weeks.

Who Should Use Phentermine?

Phentermine may be most suitable for individuals looking for a quick intervention to kick-start their weight management journey. Because of its ability to significantly suppress appetite and increase energy, it is often prescribed for people who need short-term motivation to change their habits and lose excess body weight quickly.

Phentermine may be appropriate for people who:

• Need to jump-start weight reduction and overcome a plateau
• Are not currently managing chronic heart disease, high blood pressure, or taking other medications that may pose drug interactions
• Are able to follow a 12-week treatment plan and attend regular check-ins with their healthcare professional
• Can pair the weight loss pill with a balanced diet and regular physical activity

Phentermine may be especially helpful for certain individuals who are highly motivated to lose weight but struggle with overwhelming hunger or nighttime snacking. Because it stimulates the central nervous system, it can also increase alertness and reduce fatigue, which may help patients stay active during the day.

Patients should avoid phentermine if they have:

• A history of psychological dependence or substance misuse
• Diagnosed heart disease, including arrhythmias, prior heart attacks, or high blood pressure. Phentermine is contraindicated for patients with heart disease, according to the FDA labeling information.
• Sensitivity to stimulants, which could result in trouble sleeping, rapid heartbeat, or anxiety
• Current or recent use of monoamine oxidase inhibitors (MAOIs) or other prescription drugs that affect serotonin or dopamine

Because phentermine is a controlled substance, physicians typically monitor patients closely during treatment, and prescriptions may not be renewed beyond a few months.

Who Should Use Contrave?

Contrave is often a better option for individuals who are struggling with emotional or behavioral factors that affect their eating habits. Unlike stimulant-based medications, Contrave operates by modulating dopamine and opioid receptors, which makes it especially effective for people who eat out of boredom, anxiety, or stress.

Contrave may be ideal for people who:

• Frequently deal with food cravings or impulsive eating, especially at night or in response to emotions
• Require long-term treatment and ongoing support for weight management
• Are already managing a weight-related condition such as high cholesterol, high blood pressure, or low blood sugar, and need a medication that works with their existing health plan
• Have previously tried other weight loss medications without success
• Want a non-stimulant option that won’t interfere with sleep or raise blood pressure

Patients who commit to taking Contrave long-term often benefit from gradual, sustained weight loss, especially when the medication is part of a larger plan that includes diet and exercise coaching, mental health counseling, and regular visits with a healthcare professional.

Patients should not take Contrave if they:

• Have a history of seizures or are currently using medications that lower seizure threshold
• Are experiencing or have experienced suicidal thoughts, depression, or related psychiatric conditions
• Are currently abruptly stopping alcohol, benzodiazepines, barbiturates, or anti-seizure medications, as doing so increases seizure risk
• Are pregnant, breastfeeding, or planning to become pregnant
• Are already taking other medications that may lead to adverse reactions when combined with bupropion or naltrexone

Because Contrave contains bupropion—an antidepressant also used to help people quit smoking—it has a black box warning for suicidal thoughts and self-harm in some populations, particularly young adults. It’s essential that anyone taking Contrave be monitored closely for changes in mood or behavior.

Weight Management Beyond Pills

It’s crucial to understand that neither phentermine nor Contrave—nor any other weight loss meds– should be viewed as a miracle cure. These prescription drugs can offer powerful support for people who struggle to lose weight, but they are most effective when paired with sustainable lifestyle changes that support long-term weight management and overall health.

Both phentermine and Contrave are designed to be used in conjunction with a balanced diet and consistent physical activity. Without these foundational habits, any progress made with weight loss drugs is likely to be short-lived. While these medications can help jump-start weight reduction by curbing appetite or managing cravings, they don’t replace the need for daily choices that support a healthy metabolism, muscle preservation, and body weight control.

Lifestyle Habits That Enhance Medication Results

According to many clinical studies, patients who combine prescription weight loss medication with lifestyle interventions tend to lose significantly more body weight and keep it off longer than those who rely on medication alone.

Here are several strategies that work well alongside weight loss pills like phentermine or Contrave:

• Track calories or macronutrients: Logging your food intake can help you stay within your daily calorie goals and monitor the quality of your diet and exercise plan. Many people are surprised to discover how easily high-calorie snacks or liquid calories interfere with weight loss efforts.
• Practice mindful eating: Paying attention to hunger and fullness cues can help reduce overeating and emotional snacking. Mindful eating also encourages healthier relationships with food, which supports long-term weight management.
• Get support from a coach or therapist: Behavioral counseling or cognitive-behavioral therapy can help patients identify psychological triggers for overeating. This is especially valuable for those taking Contrave, since the medication targets reward centers in the brain linked to addictive eating behavior.
• Engage in consistent physical activity: Exercise not only burns calories but also improves cardiovascular health, boosts mood, and helps preserve lean muscle mass during weight reduction. Combining weight loss medication with regular activity (such as brisk walking, strength training, or swimming) improves outcomes and supports overall health.

For many individuals, working with a registered dietitian or joining a structured program can provide accountability and personalized guidance. These additional layers of support can dramatically enhance the effects of common weight loss drugs, making it easier to stay on track and adjust course as needed.

Even tools like mobile apps, fitness trackers, or meal planning services can improve adherence to your weight management plan—especially when used under the guidance of a healthcare professional.

“Weight loss medications are not a standalone solution—they are most effective when they’re one part of a broader, strategic approach,” says Dr. Matthew Olesiak, MD. “Patients who commit to lifestyle change alongside medical treatment see better, longer-lasting results.”

In summary, successful weight loss isn’t about choosing between pills and lifestyle—it’s about combining the two in a way that supports your goals, health status, and daily routine. Whether you’re taking Contrave, using phentermine, or exploring other weight loss medications, the best long-term results come from a holistic commitment to your overall health.

Insurance Coverage & Cost

Both phentermine and Contrave are prescription drugs, but coverage varies. Insurance coverage for Contrave is more common, especially for those with qualifying health conditions. Generic phentermine tends to be less expensive out of pocket.

It’s important to check with your provider, as insurance coverage may depend on BMI, coexisting weight-related conditions, or other medications.

Risks and Drug Interactions

While phentermine and Contrave can both aid in weight loss, they carry important risks and require careful consideration, especially when taken with other medications. As prescription drugs, they must be managed under the supervision of a qualified healthcare professional to avoid serious complications, including adverse reactions, drug interactions, and health deterioration in vulnerable populations.

Phentermine

Phentermine acts on the central nervous system to suppress appetite, which can increase blood pressure and heart rate and stimulate the cardiovascular system. These effects may be dangerous for people with a history of heart disease, high blood pressure, or arrhythmias. Because of its stimulant nature, phentermine may also cause dry mouth, restlessness, and trouble sleeping, particularly if taken later in the day.

Phentermine risks include:

• Drug interactions with other weight loss medications, especially those affecting serotonin or dopamine, which may increase the risk of serotonin syndrome or hypertensive crisis
• Interference with antidepressants or MAO inhibitors, potentially leading to life-threatening events
• Elevated blood pressure, heart palpitations, and a heightened risk of cardiac strain
• Adverse effects such as anxiety, irritability, or dizziness, especially in sensitive individuals
• Risk of psychological dependence with long-term or unsupervised use due to its classification as a controlled substance

Phentermine must not be used in combination with certain common weight loss drugs, as this increases the risk of overstimulation and cardiovascular strain. For this reason, your healthcare professional will likely perform a full medication review before prescribing it.

Contrave

Because Contrave combines bupropion (an antidepressant) and naltrexone (an opioid antagonist), it presents a different set of risks and drug interactions. Bupropion can lower the seizure threshold, which makes Contrave unsafe for individuals with a history of seizures or abruptly stopping alcohol, benzodiazepines, or other sedative medications. Additionally, taking Contrave with opioid medications can lead to sudden withdrawal symptoms due to naltrexone’s blocking effects.

Contrave risks include:

• Allergic reactions, including rash, itching, swelling, or trouble breathing
• Suicidal thoughts, mood swings, or worsening depression, particularly in young adults or those with a history of mental illness
• Increased seizure risk in predisposed individuals or those combining Contrave with other medications that lower the seizure threshold
• Dangerous interactions with opioid medications due to naltrexone, an opioid antagonist
• Complications when used after abruptly stopping alcohol, which can heighten the likelihood of seizures

Because Contrave affects how some drugs are processed in the liver, it may also interfere with the effectiveness of other weight loss medications, hormonal therapies, antidepressants, or blood thinners. Patients must disclose all supplements and medications—including over-the-counter drugs—to avoid unintended adverse reactions.

Both phentermine and Contrave have the potential to cause serious side effects when combined with incompatible medications. This is especially true when patients are also being treated for high blood pressure, heart disease, depression, or chronic pain. Taking either drug without proper guidance can result in life-threatening outcomes, including cardiovascular events, seizures, or psychological distress.

“The safest approach is to view these medications as part of a coordinated care plan,” says Dr. Matthew Olesiak, MD. “Always consult a licensed healthcare professional to assess for drug interactions, review your medical history, and monitor for emerging side effects.”

Frequently Asked Questions: Phentermine vs. Contrave and Other Weight Loss Pills

If you’re researching prescription weight loss medications, it’s common to have questions about which options offer the best results, how drugs like phentermine and Contrave compare, and whether other treatments may be more effective.

The answers below address common concerns using current medical understanding and treatment guidelines.

1. Which is better, phentermine or Contrave?

It depends on your weight loss goals, health history, and how your body responds to medication. Phentermine is typically used for short-term treatment and produces faster initial results by suppressing appetite through stimulating the central nervous system. Contrave, on the other hand, is approved for long-term treatment and works by targeting both hunger and reward systems in the brain, which can help reduce cravings and emotional eating. Contrave may be a better fit for people with a history of food addiction or those seeking gradual, sustained results.

A healthcare professional can help determine which is safer and more effective for your specific needs.

2. What is the most effective weight loss pill?

The most effective weight loss pill varies by individual, but options like phentermine, Contrave, and other FDA-approved medications such as Wegovy or Qsymia have shown clinically significant results when combined with a balanced diet and regular physical activity. Effectiveness depends on factors like adherence, side effect tolerance, existing weight-related conditions, and lifestyle changes. Some people respond better to appetite suppressant medications like phentermine, while others benefit from medications that target emotional eating like Contrave.

The best weight loss medication is one that produces consistent results without triggering serious adverse reactions.

3. What weight loss pill is better than phentermine?

While phentermine is highly effective for short bursts of weight loss, some patients find greater success with long-term treatment options like Contrave, Qsymia, or Wegovy, which can be more sustainable over time. These prescription drugs may produce fewer stimulant-related side effects and offer broader mechanisms of action, such as reducing cravings or mimicking appetite-regulating hormones. People with heart disease, high blood pressure, or sensitivity to stimulants may benefit more from these alternatives.

Always speak with a healthcare professional to assess which medication aligns best with your health status and weight goals.

4. What works better than Contrave?

For some individuals, GLP-1 receptor agonists like Wegovy (semaglutide) may result in more significant body weight reduction than Contrave, especially when paired with lifestyle modifications. These medications regulate hunger hormones and slow digestion, helping people feel fuller longer. However, they can be expensive and may have different possible side effects or insurance coverage limitations.

Other weight loss medications, including Qsymia or Saxenda, may also outperform Contrave in specific patients based on metabolic needs or behavioral eating patterns. If you want to widen the search, check out our article “Phentermine vs Qsymia for Weight Loss,” for a head-to-head- comparison of these drugs. The best approach is personalized, and what works better for one person may not work as well for another.

5. Does Contrave work as well as phentermine?

In many cases, yes—especially over the long term. Contrave has been shown to support steady, meaningful weight loss, particularly in individuals who struggle with cravings or emotional eating. While phentermine often produces quicker initial results due to its stimulant effects, it’s usually prescribed for just a few weeks.

Taking Contrave consistently over several months can lead to comparable or better outcomes in terms of total body weight lost, especially when combined with diet and exercise. The choice between them should be based on personal health factors and the guidance of a healthcare professional.

Final Thoughts: Which Weight Loss Pill Is Right for You?

Choosing between phentermine vs contrave comes down to your health history, weight loss goals, and how your body reacts to each medication. Neither option works in isolation. For best results, use them as part of a comprehensive weight management strategy involving a balanced diet, physical activity, and emotional support.

If you’re struggling to lose weight and don’t know where to start, consult with a licensed healthcare professional who can evaluate your options, including common weight loss drugs, medical devices, and behavior therapy.

Always weigh the benefits against potential adverse reactions and drug interactions, especially if you’re managing heart disease, high cholesterol, or other chronic conditions.

With careful guidance, phentermine or Contrave treatments can each play a role in helping you improve your overall health, lose excess body weight, and feel more in control of your journey.

REFERENCES

Endocrine Practice

FDA