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What is Mysimba?

We answer some of your questions about Mysimba, including how it works, how to take it, and how much weight you could lose during treatment.
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Mysimba is a very interesting medication, but many people can find it difficult to pin down accurate information about what treatment looks like.

Knowing how your medication works doesn’t just give you peace of mind but helps you to identify when a treatment isn’t quite right for you.

If you’re considering starting weight management treatment and think Mysimba could be the treatment for you, you’ve come to the right place.

We’re going to answer some of your most frequently asked questions about Mysimba, including how it works, how to take it, and how much weight you could lose during your treatment.

Let’s start by getting to know more about the makeup of this medication and learn about its active ingredients.

What is Mysimba also known as?

Mysimba is sometimes known by the name of its active ingredients — Naltrexone hydrochloride and Bupropion hydrochloride.

If you’re coming to us from across the pond, you may be more familiar with its American brand name, Contrave.

No matter which brand name you’ve got on your prescription, as long as you’ve got 8mg of Naltrexone and 90mg of Bupropion in your tablet, you’re taking the same medication.

This type of naming is pretty common, for example, the medication Semaglutide is known as both Wegovy and Ozempic.

You’ll be prescribed a different brand depending on why you’re taking it, but you’ll still be taking Semaglutide either way.


Naltrexone hydrochloride is one of the two active ingredients in Mysimba, but you may also know it under the brand name Adepend.

Naltrexone is a type of medication called an opioid antagonist, and as Adepend it’s used to help patients who suffer from alcoholism during their recovery.

It blocks the receptors in your nervous system that respond to opioids, helping to reduce their alcohol cravings and making them less likely to relapse.

You may have worked out how this could also be an effective weight loss medication, but we’ll get into more of that later.

First, let’s take a look at the other active ingredient in Mysimba, Bupropion, in more detail.


Bupropion hydrochloride is also known by another brand name, so you may be more familiar with it under the name Zyban.

Like Naltrexone, Bupropion is used to help people manage addictions, specifically smoking in the case of Zyban.

However, unlike Naltrexone, the exact way Bupropion reduces the craving for cigarettes and nicotine isn’t quite as clear.

What we do know is that it works on our dopamine, noradrenaline, and serotonin receptors, so it’s more than likely that this plays a large part in reducing nicotine cravings.

Again, we’ll address how this can relate to weight loss later, but it’s safe to say that the way Bupropion works for smoking may also play into how it works as a weight management treatment.

Who is Mysimba for?

Mysimba is a medication for patients ages 18 and over who need help with weight management.

It will usually only be prescribed to those who have a BMI of 30 or above but it can also be provided to patients with a BMI of 27 or above if they are at risk of medical complications related to obesity.

These complications can include high blood pressure, type 2 diabetes, and high levels of fat in your blood.

By reaching and maintaining a healthy BMI, you can reduce your risk of these complications, even if they are not an immediate risk to you at the start of your treatment.

This is something your healthcare team may consider during your weight loss consultation and may play a part in their decision of which weight management treatment to offer you, if any.

How does Mysimba work?

Mysimba is thought to work by reducing your food cravings, making it easier for you to stick to a calorie-controlled diet.

As you may have noticed during our explanations of Naltrexone and Bupropion, both of the active ingredients are used in patients with addiction problems to help prevent relapse during their recovery.

The way that both of these ingredients help to reduce cravings for addicting substances could have a lot to do with the way it works for weight loss patients.

At this point, the exact reason why Mysimba works for weight loss isn’t known, but the evidence suggests that by working on the areas of your brain that are concerned with addiction it helps to reduce food cravings too.

Most weight loss medications work by helping you to intake fewer calories every day over a prolonged period, and Mysimba is no different, even if the way it goes about it is different to competitors like Wegovy and Saxenda.

How should Mysimba be taken?

How you will take Mysimba will differ slightly, depending on what stage of treatment you’re at.

The typical titration plan for Mysimba will see you increasing your dose slowly over a four-week period and then staying at the highest dose until your treatment ends.

However, it’s important to note that your treatment plan may differ slightly from the norm if your prescriber deems it necessary, so you should always follow their instructions carefully.

If you are following the standard treatment plan recommended by the manufacturer of Mysimba, you will take one tablet a day every morning for the first week.

In week two, you will increase your dosage to two tablets a day, one in the morning and then in the evening.

For week three, you’ll increase your dose to three tablets a day, two in the morning and one in the evening.

From week four onwards you’ll take the highest recommended dose of four tablets a day, two in the morning and two in the evening.

What is the usual dose?

Your usual dose of Mysimba will also differ depending on where you are up to in your treatment plan.

Each Mysimba tablet contains 8mg of Naltrexone hydrochloride and 90mg of Bupropion hydrochloride, so that is the daily dose you’ll be taking for your first week of treatment.

In week two, your daily dose will increase to 16mg of Naltrexone and 180mg of Bupropion, then increase to 24mg of Naltrexone and 270mg of Bupropion for week three.

When you reach week four and the highest dose of this treatment you’ll be taking a grand total of 32mg of Naltrexone and 360mg of Bupropion every day, split between your two daily doses.

Again, this reflects the standard dosage plan, so don’t worry if your prescriber has recommended that your doses are different and make sure you follow their advice.

When should Mysimba be taken?

When you should take Mysimba will depend on whether you’re taking one or two doses a day.

During your first week, you’ll only take one dose and you’ll take it first thing in the morning.

Ideally, you should take Mysimba with food, so you could take it with or just after your breakfast.

When you start taking a second dose every day you’ll take it in the evening, again with food, so it would be best to take it with your evening meal.

If you accidentally miss one of your doses you should not try to take it late and should just take your next dose at the same time you usually would.

Some of the best ways to remember to take your medication include setting an alarm on your phone to remind you, taking your medication at the same time every day, and taking your medication at the same time you usually do something else so it can serve as a reminder.

If you find that you’re consistently forgetting to take your medication you should ask your prescriber for advice, as they may need to reassess whether this is the right treatment for you.

Should you take Mysimba?

It’s difficult for us to say whether you should take Mysimba without knowing anything about you, which is why you need to go through a consultation before it will be prescribed for you.

There are a lot of factors your prescriber will need to consider before writing a prescription for weight loss medication.

They will need to know more about your BMI, your weight loss goals, anything you’ve done so far to try and lose weight, any medical conditions you have, any medications you’re taking, and that’s just for starters.

This doesn’t mean that you should be put off if you think weight management treatment could be right for you.

Even if a medication isn’t going to be the best thing for you at the moment, your prescriber will be able to offer you advice to help you get to where you want to be with your weight loss journey.

For example, they may be able to recommend resources to help you maintain a healthy diet and exercise routine or could point you towards local support options.

When will I see the results?

You should be able to see the results of Mysimba after 16 weeks if it’s the right medication for you.

This will give you time to adjust to your medication, increase to the highest daily dose, and begin your weight loss journey.

By the 16-week mark you should have lost at least 5% of your starting body weight — so if you started your treatment weighing 260lbs you should have lost at least 13lbs within 16 weeks.

Around this time your prescriber will check in with you to see how your treatment is going and they will want to know how much weight you’ve lost.

If you haven’t lost at least 5% of your starting weight then this may be an indicator that Mysimba isn’t the right medication for you and your prescriber may stop your treatment.

This isn’t the end of the world, it just means that your prescriber will need to consider where you are in your weight loss plan and whether a different medication (or no medication at all) may be a better fit for you.

Can you take this with other weight loss medications?

You shouldn’t take Mysimba at the same time as other weight loss medications.

While weight management treatments are perfectly safe by themselves, taking too much of one type of treatment can lead to unwanted side effects and can be dangerous.

For example, taking Mysimba with a medication like Semaglutide or Liraglutide, which were originally designed to help patients manage their blood sugar levels, could lead to your blood sugar falling dangerously low.

With that being said, taking Mysimba doesn’t mean you can’t take a different weight loss medication after you’ve finished treatment.

Changing weight loss medications is far from unheard of, and it can be done safely.

If you are taking Mysimba or another weight loss medication and want to switch to a medication you think may be a better fit for you we would recommend speaking to your prescriber or another healthcare professional, like your GP.

They will be able to take your current treatment into consideration, let you know more about the medication you would like to take and will ultimately decide whether they would be happy to prescribe a different treatment for you.

If they give you the go-ahead to switch to another treatment they will also be able to help you form a plan to stop your current treatment and start the new one safely.

Well there we have it, hopefully we’ve answered all of your questions about Mysimba and how it could work for you.

If you’re the type of curious cat who would like to learn more about this medication in more detail, you’re in luck!

Our team has been working away to bring you as much information about weight management medications as possible.

Here are some of our other articles about Mysimba and other weight loss treatments that you might find interesting.

Content Written By

Laura Henderson

Laura Henderson

Reviewed & Fact-Checked By

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James O'Loan

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