Mysimba Weight Loss Tablets


Prices from £99.00
In stock. Simply fill in a brief questionnaire. One of our doctors will review your order and prescribe a suitable treatment. How to Order
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Mysimba weight loss tablets are a medication used to help people who are overweight lose weight. They can help you lose 10% or more of your starting weight when taken alongside a healthy diet and exercise plan. These tablets are available in the UK and you can request Mysimba online through services like Asda Online Doctor.




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Mysimba pills are prescription-only and contain a combination of 2 active ingredients, naltrexone and bupropion, which help support weight loss. Up to 4 tablets are taken every day, increasing during your first 4 weeks of treatment.
What is Mysimba used for?
Mysimba prescriptions are given to help weight loss in adults who are overweight. This means people who are over 18 years old and have a BMI of over 30, or over 27 if they have weight-related health conditions like high blood pressure or high cholesterol.
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Scientists don’t fully understand exactly how Mysimba works, but the active ingredients affect the part of the brain that controls appetite and energy levels. This helps support weight loss in 2 ways:
- reducing a person’s appetite so they find it easier to stick to a diet
- increasing the amount of energy their body uses up, speeding up weight loss
The effect Mysimba has on suppressing appetite and increasing energy usage doesn't cause weight loss on its own. The medication only works effectively alongside a healthy diet and exercise plan, increasing how much weight you lose.
What are the ingredients in Mysimba?
Mysimba diet pills contain 2 active ingredients: naltrexone and bupropion. Both of these Mysimba ingredients work differently but help to support weight loss when taken in combination.
Naltrexone
Naltrexone is called an opioid antagonist because it blocks the effects of opioids in the brain. Because it works this way, it can be used to treat addictions like opioid abuse or alcoholism. In Mysimba, it supports the effect of Bupropion to help suppress food cravings and energy levels.
Bupropion
Bupropion has an antidepressant effect, affecting how norepinephrine and dopamine work in the brain. It also activates proopiomelanocortin (POMC) which is part of the mechanism that controls your body clock that affects appetite and energy levels. In Mysimba, the effect of POMC that bupropion has in combination with naltrexone is what allows it to promote weight loss.
How long does Mysimba take to work?
Mysimba can have an effect after the first dose but it usually takes a couple of weeks to see a significant effect. Weight loss takes time but when used properly with diet and exercise, Mysimba should help you lose at least 5% of your weight after 16 weeks.
If you haven’t lost 5% of your weight after 16 weeks of treatment then it’s recommended you stop using Mysimba and consider alternative treatment options.
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Mysimba effectiveness can be measured by how much of their starting weight patients lose during treatment compared to without Mysimba.
Mysimba makes it more likely for you to be able to lose at least 5% of your weight. It also makes it more likely you will lose 10% or more of your starting weight.
On Mysimba Without Mysimba % of people losing 5% of their body weight 37.9%
16.8%
% of people losing 10% of their body weight 22.2%
8.1%
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You should be able to lose at least 5% of your starting weight after 16 weeks of Mysimba treatment. But, you can lose up to 10% or more of your starting weight. That’s the equivalent of dropping from a starting weight of 200 pounds to 190 or even 180 pounds, or less.
Everyone’s experience of weight loss medication is different and your Mysimba results will depend on how well you stick to your diet and exercise plan.
Mysimba reviews
The active ingredient combination in Mysimba (bupropion and naltrexone) has been reviewed over 2000 times on drugs.com and has been rated 6.6 out of 10.
The same combination of ingredients under the brand name Contrave has also been reviewed over 100 times on everydayhealth.com with an average rating of 3 out of 5 stars.
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You can buy Mysimba online using services like Asda Online Doctor, which allow you to order prescription treatments remotely. You can also order repeat prescriptions online from the NHS if you’re already receiving treatment.
How to buy Mysimba tablets with Asda
Ordering Mysimba from Asda Online doctor is simple, just follow these steps:
- start a quick online assessment
- answer questions about your health
- sign in or create an account
- place your order
- one of our doctors will check your assessment
- if Mysimba is right for you, your order will be approved
- your order will be sent direct to you or to a local Asda pharmacy for collection
Our online weight loss service offers:
- no need for face-to-face consultations
- no need to travel for consultations or medication unless you want to click and collect
- free delivery as standard
- refunds on all orders that can’t be approved
- ongoing care provided by online doctor direct messaging through your patient account
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Mysimba are oral tablets which means they need to be swallowed. You should take them whole, without crushing or cutting them and use water to help you swallow them if needed.
It’s important to take Mysimba as advised by your doctor. That means the right number of pills at the right times.
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The recommended Mysimba dosage changes during the first 4 weeks of your treatment. The recommended starting Mysimba dose is one tablet once a day. The recommended maintenance dose you take from week 4 onwards is two tablets twice a day.
Morning Evening Week 1 1
0
Week 2 1
1
Week 3 2
1
Week 4 onward 2
2
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The time of day for taking your Mysimba tablets changes during your first 4 weeks of treatment:
- Week 1, 1 in the morning
- Week 2, 1 in the morning and 1 at night
- Week 3, 2 in the morning and 1 at night
- Week 4, 2 in the morning and 2 at night
It’s best to take your tablets at the times advised by your doctor and explained in the patient information leaflet that comes with your medication.
Can you take Mysimba at night?
From week 2 onwards you have to take your Mysimba at night as well as in the morning. You shouldn’t start taking it at night though, it’s recommended you take it in the morning for the first week.
What happens if you take 4 pills at once?
Taking 4 pills at once would be an overdose. The reason the pills are split into morning and evening doses is to keep the amount of medication in your system more consistent and avoid a big spike.
Having the amount of medication in your body spike can increase the risk of side effects. Only taking Mysimba in the morning could also mean the levels in your body would drop in the evening, making it more likely that you break your diet.
Can you stop taking Mysimba?
Stopping Mysimba is safe to do at any time. You won’t get withdrawal symptoms but your appetite will go back to normal levels. Because your appetite comes back after stopping it’s important to continue with your diet and exercise plan to avoid putting weight back on.
Also once you stop, any side effects you might have been having should go away too. Still, if you’re worried about your treatment or having side effects then it’s best to discuss these with a doctor. Stopping medication with help from a doctor is a good idea.
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Mysimba does come with some health risks and possible side effects like all medications. But, Mysimba should be safe for you as long as treatment has been approved by a doctor.
“Blood pressure and pulse should be measured before starting treatment with Mysimba and should be checked regularly while taking it. We would recommend at least weekly checks, especially if you already have a diagnosis of high blood pressure. If your blood pressure or pulse is consistently raised, you should stop taking Mysimba.” - Dr Babak Ashrafi, Clinical Lead for Service Expansion at ZAVA
There are some medications or health conditions that might make Mysimba unsafe, but a doctor will always check these before approving treatment. In the case of Asda Online Doctor, these are covered in the order assessment.
See the ‘Mysimba contraindications’ and ‘Mysimba interactions’ sections for more information on other medications and health conditions that affect how safe Mysimba is.
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Mysimba side effects can be quite varied, but most common side effects are mild and can go away shortly after starting treatment (usually within a few days).
Very common side effects of Mysimba affect more than 10% of people who take it and include:
- feeling sick or throwing up
- getting constipation
- headaches
Common side effects of Mysimba affect up to 10% of people who take it and include:
- feeling anxious
- feeling dizzy
- feeling shaky
- having trouble sleeping
- food tasting different
- having trouble concentrating
- feeling tired or weak
- hearing a ringing in your ears
- having a fast or irregular heartbeat
- getting hot flushes
- high blood pressure
- pain around the stomach
- sweating more than normal
- feeling itchy or getting a rash
- hair loss
- feeling irritable
- feeling jittery
For full information on all possible side effects, see the Mysimba patient information leaflet.
Get medical help right away if you any signs of serious side effects, including:
- depression or suicidal thoughts
- fits or seizures
- red itchy spots starting on your arms and legs or blisters and bleeding around the mouth, eyes, nose or genitals
- intense muscle cramps or pain
- a butterfly shaped rash on your cheeks and nose or other skin rashes or lesions
- agitation, hallucinations, coma, high temperature, unstable blood pressure, jerky reflexes, stiff muscles or serious stomach problems, if you’re taking antidepressants
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Usually side effects happen during the first 4 weeks of treatment while your dose is increasing and your body is getting used to Mysimba. If that’s the case, your side effects should start clearing up from week 5 onwards.
Some side effects can last longer than this and may be present during the whole of your course of Mysimba. These should still usually be mild, but if you find they are difficult to put up with, you should get in touch with your doctor about switching treatments.
Any side effects you still have should clear up shortly after you finish your course of Mysimba.
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Mysimba isn’t a suitable treatment for everyone. There are some other medications (drug interactions) and preexisting health conditions (contraindications) that can make Mysimba unsafe to take.
A doctor will check these before prescribing treatment so make sure to give accurate information during your consultation or assessment.
Mysimba contraindications
Mysimba is not suitable for people who:
- are allergic to the ingredients
- have uncontrolled high blood pressure
- have a history of fits
- have a current brain tumour
- are a heavy drinker
- have bipolar disorder
- have a history of eating disorders
- have severe liver disease
- have end-stage kidney disease
Mysimba interactions
You shouldn’t take Mysimba with:
- medications used to treat Parkinson’s, like phenelzine, selegiline or rasagiline
- medications containing opiates, like dextromethorphan, codeine, methadone, morphine or paregoric
There are also many medications that can increase your risk of side effects when taking Mysimba, including medications:
- that increase your risk of fits
- for treating depression
- for treating high blood pressure
- for treating irregular heart beat
- for treating cancer
- for treating Parkinson’s
- for treating heart disease or stroke
- for treating HIV and AIDS
- for treating epilepsy
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Mysimba is not the only weight loss medication available on the market. There are a range of Mysimba alternatives available to consider, including:
These treatments contain different active ingredients and vary based on who they are suitable for and their availability in the UK.
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Choosing either Mysimba or Saxenda can lead to significant weight loss. Saxenda has been shown to be a little more effective at helping patients reach 5% weight loss or more compared to Mysimba.
When comparing Mysimba vs Saxenda, it’s important to note that they vary in terms of who can safely use them, so one might be right for you when the other isn’t. They also work in different ways, so one may work for you when the other doesn’t. The only way to know for sure is by trial and error. You may be able to switch to the other if one doesn’t work out for you.
On Mysimba On Saxenda % of people losing 5% of their body weight 37.9%
51%
% of people losing 10% of their body weight 22.2%
26%
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Orlistat, sold under the brand names alli and Xenical, works differently from Mysimba. Both can be effective but Orlistat has been shown to be slightly more effective at helping people lose 10% or more of their starting weight.
On Mysimba On Orlistat % of people losing 10% of their body weight 22.2%
28% to 38%
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Wegovy is generally more effective than Mysimba at supporting weight loss. It’s now available in the UK.
On Mysimba On Wegovy % of people losing 5% of their body weight 37.9%
86%
% of people losing 10% of their body weight 22.2%
71%
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On 15mg of Phentermine, patients are more likely to lose 5% of their weight but Mysimba is more likely to lead to weight loss of 10% of starting weight or more.
Due to safety concerns, Phentermine is not widely available and not offered from Asda Online Doctor or regularly prescribed by NHS doctors, even through private prescriptions.
On Mysimba On Phentermine % of people losing 5% of their body weight 37.9%
49.9%
% of people losing 10% of their body weight 22.2%
16.0%
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One of the main differences between Mysimba and Ozempic is that Ozempic is normally used to treat diabetes and weight loss in people with diabetes but Mysimba is used for weight loss in people with or without diabetes. Asda Online Doctor does not offer Ozempic for weight loss.
Ozempic can be slightly more effective at helping people lose 5% of their starting weight but Mysimba is more likely to help you lose 10% or more of your starting weight.
On Mysimba On Ozempic % of people losing 5% of their body weight 37.9%
45%
% of people losing 10% of their body weight 22.2%
17%
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Mysimba can be an effective weight loss treatment for many people. It may be a good choice for you if you:
- are over 18
- are BMI is over 30, or 27 and you have a weight-related health condition
- don’t have any other health conditions that make Mysimba unsafe
- aren’t taking any medications that interact badly with Mysimba
You can easily order a course of treatment online from Asda Online Doctor and see for yourself how Mysimba can support your weight loss journey.
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Frequently asked questions
Is Mysimba available on the NHS?
No, Mysimba is not currently available on NHS prescription. What that means is you can’t get it for the standard NHS prescription charge. But, it doesn’t mean NHS doctors won’t prescribe it, it just means you have to get a private prescription and pay full price for Mysimba.
Does Mysimba give you energy?
This is a common misconception given the way the effect of Mysimba is usually explained. Part of the way it works is to increase the amount of energy your body uses up. This doesn’t necessarily mean you will feel more energetic. Mysimba does have an antidepressant effect so it can improve some people’s mood, but it can also cause tiredness or weakness as side effects too.
What are the risks of Mysimba?
Like all medications, Mysimba comes with a risk of side effects. Most common side effects are mild and go away in the first 4 weeks. When your doctor approves treatment, they will check your existing medications and health conditions to make sure there isn’t a serious risk to you in starting treatment.
Can you drive on Mysimba?
You can drive on Mysimba but it’s important to make sure you’re not experiencing any side effects from Mysimba that might affect your ability to drive.
For example, if you find that you are feeling dizzy, sleepy or having difficulty concentrating on your Mysimba, you should avoid driving. It is against the law to drive when you know your ability to drive is being affected by a medication you’re taking.
Can you drink alcohol on Mysimba?
No, it’s not recommended that you drink alcohol with Mysimba. This is because alcohol increases the risk of some of the side effects of Mysimba, like fits or mental health issues.
Also, alcohol contains a lot of calories and makes it difficult to stick to a diet and exercise plan anyway, so cutting out alcohol is a good idea all-round.

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.
Meet our doctorsLast reviewed: 09 Aug 2023
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Mysimba, INN-naltrexone/bupropion (europa.eu) [accessed Aug 23]
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ema-combined-h3687-en-clean (medicines.org.uk) [accessed Aug 23]
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https://reviews.everydayhealth.com/drugs/contrave [accessed Aug 23]


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