Contrave for Weight Loss: How It Works & What to Expect

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Contrave is one of the prescription medications approved by Health Canada and the FDA specifically for long-term weight management in adults who are overweight or obese.

Unlike some of the newer weight loss medications, which work primarily by mimicking gut hormones to reduce appetite, Contrave takes a different approach by targeting certain brain pathways involved in eating behaviour, food cravings, and the desire to eat.

But how effective is it realistically? Can it actually help you lose a significant amount of weight, or is it primarily useful for people who struggle with emotional eating and food cravings?

I manage weight loss patients who have used, and are currently using Contrave, and from both clinical experience and the available research, I want to shed some light on what you might realistically expect if you decide to try it yourself.

We’ll cover how Contrave works, how to take it properly, how much weight you can expect to lose, its potential side effects, and some important precautions you should know before starting.

What is Contrave?

Contrave is a combination medication containing two different drugs: bupropion and naltrexone.

Bupropion itself is mostly used as an antidepressant and is also prescribed to help people quit smoking. Interestingly, it is one of the antidepressants that is generally less likely to cause weight gain, and some people actually experience weight loss while taking it.

Naltrexone, on the other hand, is an opioid antagonist. Essentially, this means it blocks opioid receptors in the body and brain, preventing opioid drugs from producing their usual effects. It is used in the treatment of opioid use disorder and alcohol use disorder to help reduce the risk of relapse and problematic substance use.

Now, this may seem like a somewhat strange combination for a drug used for weight loss. After all, what does an antidepressant and a medication used for addiction have to do with losing weight?

Well, researchers discovered that both medications could influence eating behaviour and body weight through different mechanisms. When combined, they appeared to have complementary effects on certain brain pathways involved in appetite regulation and food cravings.

After clinical studies demonstrated that the combination could produce meaningful weight loss, Contrave was approved by the FDA in 2014 and subsequently authorized by Health Canada in 2018.

You’d be surprised how many medications have been developed or repurposed after researchers noticed unexpected effects from existing drugs. In fact, that’s how the popular hair loss medication minoxidil, also known as Rogaine, was discovered.

Minoxidil was initially investigated as a medication for other health conditions, but researchers noticed an interesting side effect: increased hair growth. Eventually, this observation led to its development as a hair loss treatment.

Contrave is another interesting example of how medications originally developed for one purpose can sometimes find an entirely different application.

Who is Contrave intended for?

Contrave is not intended to be a general-purpose appetite suppressant for anyone looking to lose a few pounds. It is approved for adults who meet certain weight-related criteria.

In Canada, the medication is indicated for adults with an initial body mass index (BMI) of:

BMI of 30 or higher: This falls within the obesity range.
BMI of 27 or higher: Provided the individual also has at least one weight-related health condition, such as type 2 diabetes, controlled hypertension, or abnormal cholesterol levels.

Contrave is intended to be used alongside a reduced-calorie diet and increased physical activity. It is not designed to replace these lifestyle changes, but rather to make it easier for some individuals to follow through with them.

It’s also important to remember that BMI is only one screening tool. Your doctor should consider your overall health, body composition, fat distribution, medical history, and weight-related complications when determining whether medication is appropriate.

Contrave vs bupropion

Because Contrave contains bupropion, many patients and healthcare practitioners have wondered whether it is possible to simply use bupropion by itself for weight loss.

And yes, bupropion is sometimes prescribed off-label to help with weight management, particularly in people who are already using it for depression or smoking cessation.

Bupropion by itself can produce some weight loss in certain individuals, and it may help reduce food cravings and reward-driven eating. However, it is important to understand that bupropion alone is not approved as a weight loss medication, and its effectiveness is not necessarily equivalent to that of the combination product.

In Contrave, naltrexone is added to complement the effects of bupropion. The combination was specifically developed to influence multiple brain pathways involved in eating behaviour, rather than relying on bupropion alone.

So while bupropion may be a reasonable medication to discuss with your doctor in certain circumstances, using it by itself does not necessarily tell you whether Contrave will work for you.

Another reason bupropion is popular as a Contrave alternative is that it is often considerably cheaper and more accessible. However, this does not mean you should simply substitute one for the other without discussing it with your doctor.

In particular, you should never combine Contrave with additional bupropion products such as Wellbutrin or Zyban to increase its effects. Doing so is contraindicated because the combined dose increases the risk of seizures and other serious adverse effects.

How does it work?

The exact mechanism by which Contrave produces weight loss is not completely understood, but researchers believe it works by targeting two important areas of the brain involved in eating behaviour.

The first is the hypothalamus, which is one of the major brain regions responsible for regulating appetite, hunger, and energy balance.

Bupropion influences dopamine and norepinephrine signalling, which can activate certain neurons involved in appetite regulation. One group of these neurons is known as pro-opiomelanocortin, or POMC, neurons. These neurons are associated with signals that help regulate food intake and satiety.

Naltrexone appears to complement this activity by blocking opioid receptors involved in feedback mechanisms that can otherwise limit the effects of these appetite-regulating neurons.

The second area involves the mesolimbic dopamine pathway, which is associated with the reward system in the brain.

This is particularly interesting because eating isn’t always about satisfying physical hunger. Sometimes, we eat because food tastes good, provides comfort, relieves stress, or simply makes us feel better.

These reward-related pathways can influence our desire to eat even when our bodies don’t necessarily need additional food.

By influencing these different pathways, Contrave may help reduce the rewarding sensations associated with food and make it easier to resist certain cravings and impulsive eating behaviours.

However, it’s important not to oversimplify its effects. Contrave doesn’t necessarily eliminate physical hunger, and it doesn’t directly block calorie absorption or dramatically increase your metabolism.

The end result is that some people find themselves eating less, particularly because they have an easier time controlling their desire to eat, rather than because they constantly feel full.

How to take Contrave properly

One of the most important things to understand about Contrave is that you should not start taking the full dose immediately.

Instead, the dosage is gradually increased over four weeks. This process, known as titration, helps your body adjust to the medication and may reduce the likelihood and severity of certain adverse effects.

Each Contrave tablet contains 8 mg of naltrexone hydrochloride and 90 mg of bupropion hydrochloride.

The usual dosing schedule for adults is as follows:

Week 1: Take one tablet in the morning.
Week 2: Take one tablet in the morning and one tablet in the evening.
Week 3: Take two tablets in the morning and one tablet in the evening.
Week 4 onward: Take two tablets in the morning and two tablets in the evening.

This brings the usual maintenance dose to four tablets per day, providing a total of 32 mg of naltrexone and 360 mg of bupropion daily.

This is the standard approved schedule, but your prescriber may recommend a different maximum dose or adjustment depending on your kidney function, liver function, other medications, and ability to tolerate treatment. For example, lower maximum doses are required in certain patients with kidney or liver impairment.

There are also a few important administration instructions:

Take it with food: Contrave is generally taken with meals, once in the morning and once in the evening.
Avoid high-fat meals when taking it: High-fat meals can significantly increase the amount of both medications absorbed into your bloodstream. This may increase the risk of adverse effects, including seizures.
Swallow the tablets whole: Do not cut, crush, or chew the tablets, as this can interfere with their extended-release formulation.
Don’t double up on missed doses: If you forget a dose, skip it and simply resume your regular schedule with the next dose.
Don’t exceed the recommended dose: Taking additional tablets to accelerate weight loss or suppress cravings more aggressively can increase the risk of seizures and other complications.

One particularly important point is that you should not take Contrave with a high-fat meal. This doesn’t mean you need to eliminate healthy fats from your overall diet. Rather, it means avoiding taking your medication alongside a particularly high-fat meal because it can substantially increase drug exposure.

How long should you take Contrave before deciding whether it works?

Another important consideration is that Contrave is not necessarily going to work immediately.

Because the dose is gradually increased over four weeks, you may not experience the full effects of the medication until you have reached your maintenance dose.

Health Canada’s product monograph specifically recommends evaluating your response after 12 weeks at the maintenance dosage.

If you have not lost at least 5% of your initial body weight by that point, the medication should generally be discontinued because you are unlikely to achieve and maintain clinically meaningful weight loss by continuing it.

Since it takes approximately four weeks to reach the full maintenance dose, this means that you would generally be reassessed around 16 weeks after initially starting Contrave.

For example, if you started at 100 kg, you would generally need to lose at least 5 kg by the appropriate reassessment point to justify continuing treatment.

This is a useful rule because it prevents people from spending months or even years taking a medication that isn’t producing meaningful results.

Side effects

Unfortunately, this is one of the biggest drawbacks of Contrave.

While some people tolerate it relatively well, others struggle considerably with the adverse effects, particularly during the first few weeks while their dosage is increasing.

Headaches, dizziness, and nausea are some of the more common issues I have observed. Some patients report particularly uncomfortable episodes of dizziness, sometimes severe enough that they feel as though they might faint.

Nausea is another major complaint, alongside other gastrointestinal issues like constipation, stomach pain, and vomiting.

In clinical trials, adverse effects were also a significant reason why people discontinued the medication. Approximately 24% of people taking Contrave discontinued treatment because of adverse reactions, compared with approximately 12% of those taking placebo.

In other words, tolerability is a genuine concern, and it’s something you should consider before deciding whether Contrave is the right medication for you.

Based on the Canadian product monograph, the common adverse effects reported in clinical trials include the following:

Common side effects:

Nausea (33%)
Constipation (19%)
Headache (18%)
Vomiting (11%)
Dizziness (10%)
Insomnia (9%)
Dry mouth (8%)
Diarrhea (7%)
Anxiety (4%)
Fatigue (4%)
Hot flushes (4%)
Tremors (4%)
Urinary tract infections (3%)
Hypertension (3%)
Upper abdominal pain (4%)
Excessive sweating (3%)

These percentages represent the approximate proportion of participants reporting each adverse effect in the clinical safety studies. They are not necessarily the percentage of people who will experience these problems in everyday practice, and the rates vary depending on the study population.

It’s also worth noting that nausea, constipation, and vomiting are particularly associated with the initial dose-escalation period. In clinical studies, most nausea occurred within the first four weeks, and many gastrointestinal symptoms improved as patients adjusted to treatment.

However, this does not mean you should simply force yourself to tolerate severe symptoms. If you are experiencing persistent vomiting, significant dizziness, dehydration, or other debilitating effects, speak with your prescriber. You may need an adjustment or to discontinue the medication.

Serious and less common side effects

Beyond the usual gastrointestinal and neurological side effects, there are several more serious risks associated with Contrave that deserve particular attention.

Remember that Contrave contains two different medications, each with its own safety considerations. Some of these complications are rare, but they can be serious when they occur.

Potentially serious side effects include:

Seizures: Bupropion can lower the seizure threshold, meaning it makes seizures more likely in susceptible individuals. The incidence in Contrave clinical trials was approximately 0.1%, compared with 0% in the placebo group. The risk increases with excessive dosing, certain medical conditions, and interactions with other medications.
Suicidal thoughts or behavioural changes: Bupropion carries important warnings associated with antidepressant use, including the potential for worsening depression, agitation, unusual behavioural changes, and suicidal thinking or behaviour. Although the obesity trials did not demonstrate an increased rate of suicidality compared with placebo, people should still be monitored, particularly during treatment initiation and dosage changes.
Serotonin syndrome: This is a rare but potentially life-threatening reaction that can occur when certain medications affect serotonin signalling, particularly when Contrave is combined with some antidepressants or migraine medications. Symptoms can include agitation, confusion, sweating, fever, tremors, muscle stiffness, and changes in heart rate or blood pressure.
Liver injury: Naltrexone has been associated with liver-related complications, and rare cases of serious drug-induced liver injury have been reported. Symptoms such as yellowing of the skin or eyes, dark urine, persistent abdominal pain, or unusual fatigue should be medically assessed.
Severe allergic or skin reactions: Rare reactions can include facial swelling, difficulty breathing, widespread rashes, blistering, or severe skin conditions such as Stevens-Johnson syndrome.
Increased blood pressure and heart rate: Contrave can increase both blood pressure and resting heart rate, particularly during the first few months of treatment. This is an important consideration for people with existing cardiovascular problems.
Changes in mood or manic episodes: Bupropion can sometimes trigger agitation, hypomania, or mania in susceptible individuals, particularly those with bipolar disorder or an underlying predisposition.

It’s important to understand that these serious complications are not equally common. Seizures, for example, occurred in approximately 0.1% of participants in clinical trials, while some other complications have been reported primarily through post-marketing surveillance, making their exact frequency difficult to determine.

As a precaution, anyone considering Contrave should be screened for relevant medical conditions and medications before starting treatment. Blood pressure and pulse should be checked before treatment and monitored periodically afterward.

New suicidal thoughts, a seizure, severe allergic symptoms, or symptoms suggestive of serotonin syndrome require immediate medical attention. You should also seek medical attention promptly if you develop signs of acute hepatitis or a serious skin reaction.

Who should NOT take Contrave?

Because of the potential complications associated with bupropion and naltrexone, there are several situations where Contrave should not be used.

According to the Canadian product monograph, Contrave is contraindicated in individuals with the following conditions or circumstances:

Uncontrolled high blood pressure: Contrave can increase blood pressure and heart rate, potentially making existing hypertension more dangerous.
A seizure disorder or previous history of seizures: Bupropion can lower the seizure threshold and increase the risk of another seizure.
Current or previous anorexia nervosa or bulimia: These eating disorders are associated with an increased seizure risk when taking bupropion.
Taking other bupropion-containing medications: This includes medications such as Wellbutrin and Zyban. Combining them with Contrave can result in excessive bupropion exposure.
Chronic opioid use or acute opioid withdrawal: Naltrexone blocks opioid receptors and can interfere with opioid medications or trigger sudden withdrawal in people who are physically dependent on them.
Abrupt discontinuation of alcohol, benzodiazepines, sedatives, or antiepileptic medications: Sudden withdrawal from these substances can independently increase the risk of seizures, making concurrent Contrave treatment unsafe.
Taking monoamine oxidase inhibitors (MAOIs): These medications must be discontinued for at least 14 days before starting Contrave.
Taking thioridazine: This medication can interact with bupropion and increase the risk of serious cardiac complications.
Pregnancy: Weight loss during pregnancy offers no potential benefit and may pose risks to the developing fetus.
Severe liver impairment or end-stage kidney disease: Drug exposure and the risk of complications may become excessive in these circumstances.
Known hypersensitivity: Anyone with a serious allergy to the medication or its ingredients should not take it.

There are also other situations where additional caution is required, even if the medication is not automatically contraindicated. These include controlled hypertension, bipolar disorder, a history of head trauma, certain psychiatric conditions, kidney or liver impairment, and medical conditions that could increase the risk of seizures.

For this reason, it’s particularly important to provide your doctor with a complete medication list, including antidepressants, pain medications, sleeping medications, supplements, and any over-the-counter products you use.

Important: Contrave and opioid pain medications

This is one of the most important precautions associated with Contrave, and something that many people may not realize when starting the medication.

Because naltrexone blocks opioid receptors, it can interfere with the effects of opioid-containing medications, including common prescription painkillers such as oxycodone, morphine, codeine, hydrocodone, and fentanyl. It can also interfere with tramadol, methadone, and buprenorphine.

This creates two major problems.

First, if you are regularly taking opioid painkillers, Contrave may prevent these medications from providing adequate pain relief. This can become particularly problematic if you require surgery, dental procedures, or emergency treatment for an injury.

Second, if you are physically dependent on opioids, starting naltrexone can trigger sudden and potentially severe opioid withdrawal.

For people previously dependent on short-acting opioids, an opioid-free interval of at least 7 to 10 days is generally recommended before starting Contrave. People transitioning from methadone or buprenorphine may require a longer interval, sometimes up to two weeks.

These intervals are not a substitute for medical assessment. Your doctor must determine whether you are sufficiently free of opioids before starting treatment.

Another concern is that naltrexone can make it dangerous to try to overcome its opioid-blocking effects by taking larger amounts of opioid medication. This can result in a potentially fatal overdose.

There is also an increased overdose risk after stopping Contrave, because the opioid-blocking effects gradually wear off and someone may have a reduced tolerance to opioids compared with what they previously used.

If you are taking Contrave, always tell your doctor, dentist, surgeon, and other healthcare professionals before undergoing a procedure or receiving pain treatment. Never attempt to overcome the opioid-blocking effects by increasing your opioid dose.

Drug interactions to watch out for

Beyond opioid medications, bupropion can affect the way your body processes several other medications.

One particularly important mechanism involves an enzyme known as CYP2D6. Bupropion inhibits this enzyme, which means that certain medications normally broken down through this pathway may remain in your bloodstream at higher concentrations.

Some examples of medications that may be affected include:

Some antidepressants, including certain SSRIs and tricyclic antidepressants.
Some antipsychotic medications, including risperidone and haloperidol.
Certain beta-blockers, particularly metoprolol.
Some heart rhythm medications, including flecainide and propafenone.
Tamoxifen, which requires activation through CYP2D6 and may become less effective when combined with bupropion.

Another concern involves combining Contrave with certain serotonergic medications, including some antidepressants. This may increase the risk of serotonin toxicity and requires careful consideration by your prescriber.

There are also interactions involving medications that affect the CYP2B6 enzyme, such as clopidogrel, which can influence the amount of bupropion circulating in your body and potentially require a dosage adjustment.

Finally, people with diabetes who are taking insulin or medications such as sulfonylureas may need closer blood glucose monitoring. As weight decreases and dietary intake changes, the risk of hypoglycemia can increase unless diabetes medications are adjusted appropriately.

These are only some examples. The most important thing is to have your complete medication regimen reviewed before beginning Contrave, rather than assuming that your existing medications will be compatible.

Drinking alcohol on Contrave

There are some particularly important concerns about drinking alcohol while taking Contrave.

Bupropion can lower your tolerance to alcohol, meaning you may experience stronger effects from an amount of alcohol that would normally be manageable for you.

Alcohol consumption while taking Contrave may also increase the risk of seizures and certain allergic or hypersensitivity reactions. For these reasons, the Canadian product monograph recommends avoiding alcohol altogether while taking the medication.

There is another important consideration that is sometimes overlooked. If you are someone who drinks heavily or has developed a physical dependence on alcohol, suddenly stopping alcohol consumption can itself trigger withdrawal symptoms and significantly increase your risk of seizures.

This is especially problematic because Contrave is contraindicated during abrupt alcohol withdrawal due to the additional seizure risk associated with bupropion.

Therefore, if you regularly drink heavily, you should speak with your doctor before starting Contrave. Do not suddenly discontinue heavy alcohol consumption without an appropriate medical plan, as alcohol withdrawal can be dangerous in its own right.

Contrave diet plan

Although there is no specific diet you need to follow with Contrave, you will still need to have an effective weight loss diet that you are already following, or plan to follow.

Contrave is officially intended to be used alongside a reduced-calorie diet and increased physical activity. In other words, the medication is designed to make your weight loss plan easier to follow, not replace the need for one.

Your selected diet should also be effective at managing hunger properly, since Contrave doesn’t necessarily eliminate physical hunger, even if it helps reduce certain cravings and impulsive eating behaviours.

This is an important distinction. You might find yourself no longer constantly thinking about snacks, desserts, or fast food, but that doesn’t mean your stomach will necessarily feel full throughout the day.

For this reason, I would prioritize a dietary approach that helps manage both hunger and cravings.

Diets that emphasize more protein and healthy fats, alongside sufficient fibre, can be particularly useful for improving satiety and making a calorie deficit easier to maintain.

Some examples include a calorie-controlled Mediterranean diet or a lower-carbohydrate diet, depending on your preferences and how your body responds.

A Mediterranean-style eating pattern can be particularly useful because it emphasizes vegetables, legumes, fruits, whole grains, fish, nuts, olive oil, and other nutrient-dense foods. You can read more about it in my Mediterranean diet overview.

I would also recommend following a relatively structured dietary routine, at least initially. Contrave may make it easier for some people to avoid impulsive food choices, so this is a good opportunity to establish consistent meal times, portion control, and healthier eating habits.

That doesn’t mean you need to follow an extremely restrictive diet. In fact, a diet that is too restrictive may be difficult to sustain, especially if you are still experiencing physical hunger.

Instead, focus on building a realistic calorie deficit, eating sufficient protein and fibre, maintaining regular physical activity, and creating habits that you can continue long after you stop taking medication.

Contrave may also be helpful for people who are trying to develop more mindful or intuitive eating habits. If the medication reduces impulsive snacking or reward-driven eating, you may find it easier to distinguish between actual hunger and the desire to eat for pleasure or comfort.

However, medication should not replace learning how to recognize hunger, fullness, and emotional eating patterns. Those skills are important for long-term weight management regardless of which medication you use.

Does Contrave work better with certain foods?

There is no particular food or diet that has been proven to make Contrave dramatically more effective.

However, there are a few dietary strategies that can complement its effects.

First, prioritize protein. Foods such as eggs, fish, chicken, Greek yogurt, and lean meat can help improve satiety and preserve muscle mass during weight loss.

Second, increase your intake of fibre-rich foods. Vegetables, legumes, berries, and whole grains can help improve fullness and digestive regularity, which may be particularly useful because constipation is one of the common side effects of Contrave.

Third, maintain adequate hydration. This is especially important if you experience nausea, vomiting, constipation, or reduced food intake while adjusting to the medication.

Finally, avoid taking Contrave with a particularly high-fat meal, as discussed earlier. This is a medication administration precaution, not a recommendation to completely eliminate healthy fats from your diet.

Ultimately, the best diet is one that creates a sustainable calorie deficit while keeping you adequately nourished and making it easier to stay consistent over the long term.

How effective is Contrave?

Now, this is probably the biggest question people have when considering Contrave.

It sounds promising to have a medication that can potentially reduce cravings and make it easier to control eating behaviour, but how much weight are you actually going to lose?

Fortunately, we have several large clinical trials that can give us a reasonable idea of what to expect.

In one major 56-week clinical trial known as COR-I, adults who were overweight or obese were assigned to receive either Contrave or a placebo. Both groups also received lifestyle advice, including dietary changes and increased physical activity.

At the end of the study, participants taking Contrave lost an average of approximately 5.4% of their initial body weight, compared with approximately 1.3% in the placebo group.

In practical terms, someone weighing 100 kg at the beginning of the study would have lost approximately 5.4 kg on average while taking Contrave, compared with approximately 1.3 kg in the placebo group.

Another clinical trial, COR-II, reported average weight loss of approximately 6.4% with Contrave compared with 1.2% with placebo after 56 weeks.

We also have another interesting study called COR-BMOD, which examined Contrave alongside a much more intensive behavioural modification program.

In this study, participants received 28 group counselling sessions over 56 weeks, alongside dietary and exercise recommendations. Those taking Contrave lost approximately 8.1% of their initial body weight, compared with 4.9% in the placebo group.

This is particularly interesting because it demonstrates that medication and behavioural interventions can work together. The medication was not replacing lifestyle changes; it was being used to complement them.

In people with type 2 diabetes, however, the average results were somewhat less impressive. One study found that participants taking Contrave lost approximately 3.7% of their initial body weight, compared with 1.7% in the placebo group.

Overall, these studies suggest that Contrave can produce meaningful weight loss in some people, but the average results are relatively modest.

Another important point is that weight loss varied significantly between individuals. Some people lost more than 10% of their body weight, while others experienced very little weight loss despite taking the medication.

So while the average results are useful, they don’t necessarily tell you exactly what will happen when you start taking Contrave yourself.

How many people actually respond to Contrave?

Looking at the percentage of people who achieve a clinically meaningful amount of weight loss can sometimes be more useful than looking at average weight loss alone.

For example, in the COR-I study, approximately 42% of participants taking Contrave lost at least 5% of their initial body weight, compared with approximately 17% of those taking placebo.

That means roughly four out of ten people taking Contrave achieved at least 5% weight loss in that particular study, while the majority did not reach that threshold.

This is an important distinction because people sometimes assume that taking a weight loss medication automatically means they will experience substantial weight reduction.

Unfortunately, that’s not how these medications work. Some individuals respond very well, some respond moderately, and others may find that the medication does very little for them.

This is precisely why the recommendation to discontinue Contrave when weight loss is less than 5% after 12 weeks at the maintenance dose is so important.

What I have observed in practice

From my experience, Contrave definitely does not work for everyone, but in the patients I’ve observed for whom it does work, it often seems to function more like a craving and reward-driven eating suppressant than a conventional appetite suppressant.

It’s kind of a different type of appetite suppressant, in that it often seems more effective at reducing the desire to eat rather than eliminating physical hunger.

Check out my article for a more detailed breakdown between the two, but the difference between cravings and hunger is kind of like the difference between wanting to eat and needing to eat.

Cravings are a desire to eat. Your body may not actually need the food, but you still want it. Hunger, on the other hand, is your body telling you that it needs more nourishment and energy.

For example, imagine you’ve just eaten a full meal and you’re no longer physically hungry. However, someone brings out a plate of your favourite dessert, and suddenly you find yourself wanting to eat again.

That’s a good example of reward-driven eating. Your body may not need additional food, but the pleasurable sensation associated with eating can still motivate you to keep going.

Contrave may help reduce this desire to eat, particularly for people who find themselves constantly thinking about food, snacking out of boredom, or eating for emotional comfort.

However, if you’re actually hungry, Contrave may not do much to reduce that hunger. You may still need a substantial amount of food to feel satisfied, even if your cravings have improved.

This is why I wouldn’t necessarily expect Contrave to completely eliminate your appetite. Its effects are more nuanced, and different individuals may experience different changes in their eating behaviour.

Why does Contrave sometimes take several weeks to work?

I do notice that it can take a few weeks before some people begin experiencing the more noticeable effects of Contrave.

Unlike certain appetite-suppressing medications that can produce noticeable changes relatively quickly, Contrave requires a gradual dosage increase, and its effects on eating behaviour may become more apparent over time.

This means that the first few weeks can sometimes be frustrating. You’re dealing with the possibility of nausea, headaches, dizziness, or other adverse effects, but you might not yet be experiencing much improvement in your cravings or eating behaviour.

However, not everyone needs several weeks to notice an effect. Some people experience changes relatively early, while others may never develop a meaningful response.

It’s important not to increase your dosage faster than recommended just because you aren’t noticing any immediate weight loss. The gradual titration schedule exists for an important safety reason.

Does Contrave cause rebound hunger or weight gain after stopping?

One concern I’ve encountered with patients is that cravings and eating urges can return after discontinuing Contrave, particularly in people who previously found the medication very effective.

This makes sense when you consider how the medication works. Contrave changes certain signals involved in appetite regulation and food reward, but it doesn’t permanently rewire your brain or eliminate the underlying biological and behavioural factors contributing to weight gain.

Once the medication is discontinued, its effects gradually wear off. For some individuals, the desire to snack, emotional eating, and food cravings may return toward their previous levels.

This doesn’t necessarily mean that everyone experiences an unusually strong rebound effect, but weight regain is a recognized problem when effective obesity medications are discontinued.

In fact, current obesity management guidelines emphasize that these medications are generally intended for long-term treatment when they are effective and well tolerated, rather than as short-term fixes.

This is another reason why it is so important to use the time you spend taking Contrave to develop sustainable dietary, behavioural, and lifestyle habits.

Contrave vs newer GLP-1 weight loss medications

One question that comes up quite often is whether Contrave is still worthwhile now that we have newer weight loss medications such as semaglutide and tirzepatide.

These medications work quite differently from Contrave. Semaglutide and tirzepatide act on gut hormone pathways involved in appetite, fullness, food intake, and metabolic regulation.

And when it comes to average weight loss, these newer medications generally have a considerable advantage.

For example, large clinical trials of higher-dose tirzepatide have reported average weight reductions in the range of approximately 20% or more over 72 weeks, depending on the dose and analysis used. This is considerably greater than the approximately 5% average weight reduction reported in one of the major Contrave trials.

However, these figures come from separate clinical trials involving different populations, treatment periods, and study designs. They should not be interpreted as a direct head-to-head comparison.

The 2025 Canadian clinical practice guideline update continues to recognize naltrexone/bupropion as an approved long-term weight management option, alongside medications such as semaglutide and tirzepatide.

However, the newer medications have stronger evidence supporting their average weight-loss effects and certain additional health benefits in specific populations.

So does this mean Contrave is obsolete? Not necessarily.

Contrave may still be a reasonable option for people who prefer an oral medication, have difficulty accessing or affording newer treatments, or experience meaningful improvements in their cravings and eating behaviour with the combination.

It also has a different set of potential side effects and contraindications. For example, people who require opioid pain medications may not be suitable candidates for Contrave, regardless of how effective it might otherwise be for weight management.

Ultimately, the best medication is not necessarily the one that produces the largest average weight loss in a clinical trial. It is the one that provides meaningful benefits for your health while remaining safe, tolerable, accessible, and appropriate for your individual circumstances.

Can Contrave improve blood sugar or cholesterol?

Another potential benefit of Contrave is that the weight loss it produces can lead to improvements in certain metabolic health markers.

Clinical trials have reported improvements in waist circumference, triglycerides, HDL cholesterol, and certain measures of glucose control among people taking Contrave.

Some of these improvements are likely related to the reduction in body weight itself, although changes in eating behaviour and other metabolic effects may also contribute.

One particularly interesting finding comes from the COR-Diabetes trial, which studied overweight and obese individuals with type 2 diabetes.

Participants taking Contrave experienced a greater reduction in HbA1c, a marker of average blood sugar levels, compared with those taking placebo. The average weight loss was also greater in the Contrave group.

However, these improvements should not be confused with proof that Contrave prevents heart attacks, strokes, or other major cardiovascular events. Its effect on cardiovascular morbidity and mortality has not been established.

People with diabetes should also be monitored carefully when starting Contrave, particularly if they use insulin or medications that can cause low blood sugar. As weight and food intake decrease, their diabetes medication requirements may change.

Should you try Contrave?

So, who is Contrave actually best suited for?

Based on its mechanism of action, clinical trial results, and the experiences I’ve observed in practice, I think Contrave is particularly worth discussing for people who struggle with reward-driven eating, frequent cravings, and impulsive snacking.

For example, if you constantly find yourself reaching for snacks even when you aren’t hungry, or you struggle to resist fast food, desserts, and other highly rewarding foods, Contrave may help you gain better control over those behaviours.

If you’re an emotional eater and tend to reward yourself with food, or eat as a way to soothe negative emotions, Contrave may help reduce some of the urges associated with those behaviours.

However, I wouldn’t assume that everyone who experiences emotional eating will automatically respond to Contrave. Emotional eating is a complex behaviour that can involve stress, sleep deprivation, mental health conditions, learned habits, and other factors. Medication may help some individuals, but it does not address every underlying cause.

Contrave may also be less appealing for people whose primary difficulty is persistent physical hunger, since it does not reliably eliminate the need to eat or produce the same degree of appetite reduction seen with some newer weight loss medications.

If you do decide you’d like to explore using it, keep these five things in mind:

Get screened thoroughly before starting. Contrave interacts with numerous medications and is unsuitable for people with certain medical conditions. Your doctor should review your blood pressure, seizure risk, psychiatric history, alcohol use, opioid use, kidney and liver function, and existing medications.
Be prepared for the initial side effects. Many people starting Contrave experience nausea, headaches, dizziness, constipation, or insomnia, particularly during the first few weeks. The gradual dosage increase is designed to improve tolerability, and many gastrointestinal symptoms settle over time. However, you should not force yourself to tolerate severe or debilitating adverse effects.
Give it an appropriate trial, but know when to stop. The medication should be evaluated after 12 weeks at the maintenance dose. If you have not lost at least 5% of your initial body weight, continued treatment is generally not recommended.
Build long-term habits while taking it. If Contrave helps reduce your cravings and impulsive eating, use that opportunity to establish a sustainable diet, regular exercise routine, and healthier relationship with food. Otherwise, you may find that your previous eating habits return after stopping the medication.
Think carefully about whether it is the best medication for your circumstances. Bupropion alone is sometimes prescribed off-label for weight management, but it is not a guaranteed substitute for Contrave. You should also consider other approved weight loss medications, especially if your main goal is achieving more substantial weight reduction or if you have medical conditions that make Contrave less suitable.

One additional point worth emphasizing is that Contrave is generally intended as a long-term treatment when it is effective and well tolerated. You should not assume that you can simply take it for a few months, lose the weight, and permanently eliminate the underlying tendency to regain it.

Weight management is a long-term process, and medication should ideally be part of a broader strategy that addresses your nutrition, physical activity, eating behaviours, sleep, and other health factors.

Of course, Contrave isn’t necessarily the right choice for everyone. Some people may achieve better results with other medications, more intensive behavioural support, or a combination of different approaches under medical supervision.

Summary

Overall, Contrave is a legitimate and clinically supported weight loss medication that may be particularly helpful for people who struggle with food cravings, reward-driven eating, and impulsive snacking.

Its combination of bupropion and naltrexone appears to influence both appetite-regulating and reward-related brain pathways, potentially making it easier for certain individuals to reduce their overall food intake.

However, its average weight loss is relatively modest compared with some newer obesity medications, and it certainly does not work for everyone.

One of the biggest disadvantages is its side effect profile. Nausea, constipation, headaches, dizziness, and insomnia are relatively common, and a meaningful proportion of people discontinue treatment because they cannot tolerate it.

There are also several important safety considerations, particularly its effects on blood pressure, seizure risk, psychiatric health, and interactions with opioid medications and other prescription drugs.

The first few weeks of taking Contrave may be the most difficult, since the dosage is gradually increased and the medication may not have produced its full benefits yet. However, if you cannot tolerate the adverse effects, you should discuss your options with your doctor rather than simply forcing yourself to continue.

Most importantly, don’t forget to continually build good dietary and lifestyle habits while you’re taking Contrave. For example, take steps to reduce your idle snacking and develop more consistent eating routines.

Think of Contrave as a tool that may make it easier to implement those changes, rather than a medication that will do all the work for you. The ultimate goal should be to improve your health and develop sustainable habits that support long-term weight management, whether or not you remain on the medication.

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Citations

bupropion/naltrexone (Rx) https://reference.medscape.com/drug/contrave-bupropion-naltrexone-999933

Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. https://pubmed.ncbi.nlm.nih.gov/20673995/

Greenway FL, Dunayevich E, Tollefson G, et al. Comparison of combined bupropion and naltrexone therapy for obesity with monotherapy and placebo. JAMA. 2010; 304(16): 1810-1818.

Highlights of prescribing info (FDA). https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/200063s000lbl.pdf

Naltrexone/Bupropion ER (Contrave) Newly Approved Treatment Option for Chronic Weight Management in Obese Adults https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771085/

Naltrexone SR/Bupropion SR (Contrave) A New Approach to Weight Loss in Obese Adults https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3138366/

Wadden TA, Foreyt JP, Foster GD, et al. Weight loss with naltrexone SR/bupropion SR combination therapy as an adjunct to behavior modification: the COR-BMOD trial. Obesity (Silver Spring). 2011; 19(1): 110-120.