Mysimba is a branded weight loss medication developed and marketed by Consilient Health Ltd pharmaceutical company. Known as Contrave in the US, Mysimba was granted a licence in 2017, making it one of the most recent slimming pills that appeared on the market. Available in the form of a prolonged-release tablet, Mysimba is taken once daily over the course of the first week of the treatment, with the dose gradually increasing for three additional weeks afterwards. This new addition to the medical markets in the UK is also a combination treatment, based on two active ingredients, unlike other better-known weight loss medications on the European markets.

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How can Mysimba help me lose weight?

Mysimba easily stands out among the competition due to its unique mechanism of action based on two separate active ingredients called bupropion and naltrexone. The former, bupropion, acts within the body by facilitating the activity of dopamine in the brain, thus limiting the user’s appetite while at the same time slightly changing the way energy is spent by the body. On the other hand, naltrexone will work by reducing the cravings for food, making sticking to your diet plan much easier and significantly less difficult.

The study conducted in the US, based on the American version of the medication, Contrave, showed that on average, people using this medication managed to lose roughly 5% of their body weight over the period of 13 months.

Can I buy Mysimba online in the UK?

Yes, it is possible to obtain this medication online. However, if you are looking to buy Mysimba in the UK, you should keep in mind that this is a prescription-only medicine and this is true regardless of whether you will buy it online or in person, at a local pharmacy. This means that even if you decide to buy Mysimba online, you will still have to possess a valid prescription issued by a certified medical professional.

Buying Mysimba first time

If it is your first time buying Mysimba online, you will first have to obtain a prescription from the doctor employed at the online clinic of your choice. This involves providing the doctor with all the relevant information needed to properly assess your condition and your suitability for the specific treatment, just like it would be the case with a regular face-to-face appointment with a doctor. However, in case of an online clinic, instead of the conventional consultations, you will talk to a doctor either via specialised chat app or, more commonly, you will be asked to fill in a customised medical questionnaire that will allow doctor to gain a detailed insight into your medical profile and history so he can correctly assess your suitability for Mysimba treatment. This makes Mysimba the only prescription-only medication in the UK alongside orlistat-based weight loss pills such as Xenical and Alli.

Renewing Mysimba prescription

If you are simply looking to renew an already existing Mysimba prescription, then the process will be somewhat shorter. Of course, the doctor will still ask you a couple of questions to confirm that Mysimba is suitable for you and you will have to present the proof that the prescription has already been issued in the past. If everything checks out, the doctor will renew your prescription and have the medicine sent to the address you provided. The package will be delivered in discreet plain packaging within the timespan defined by the company’s business model.

How is Mysimba used?

In order to ensure best possible results and at the same time minimise the risk of potential side effects, you should always use Mysimba exactly as instructed by your prescriber. What follows is a brief overview of some of the most central guidelines you should keep in mind when using this medicine. However, the text below is not intended to be used as a substitute for the official information on the topic, nor your doctor’s instructions which should always be your first source of information.

  • In order to be effective, Mysimba has to be used as a part of a wider weight loss programme including both diet and exercise plan
  • Mysimba shouldn’t be used by people affected by hypertension, so be sure to check your blood pressure prior to commencing the treatment
  • The starting dose of one tablet per day will be gradually increased over the first four weeks of the treatment
  • At the start of second week of the treatment, the dose will be increased to two tablets per day
  • At the start of the third week, you should take two pills in the morning and one in the evening
  • Finally, from the beginning of the fourth week, you should be taking two tablets in the morning and two in the evening
  • You should continue taking this dose for the remainder of your treatment
  • Mysimba has been known to cause sleeping difficulties if taken just prior to bedtime
  • Your treatment will be reviewed after 16 weeks and at regular intervals after that period, until the doctor decides that you should halt the treatment
  • Take the tablets whole with water, ideally at the same time as food
  • Never exceed the prescribed dose
  • If you accidentally miss a dose, simply skip it and continue with the treatment as usual
  • Never try to compensate for a missed dose by doubling the next one

What are Mysimba side effects?

As is the case with all medications, Mysimba can also cause various side effects in people susceptible to them. And while not everybody using this medication will experience side effects, it is still important to learn about what could go wrong so you can differentiate between those side effects which might require you to halt the treatment and seek immediate medical assistance and those which can be unpleasant, but not really dangerous.

On top of that, Mysimba is designated as a ‘black-triangle’ medication in the UK, meaning that this medicine is still monitored for its capacity to cause side effects, so some unforeseen reactions are still possible, although the chances are rather slim. But, in case you notice any side effects not listed in the official patient information leaflet that is issued within every pack of Mysimba, you should report them to the MHRA through the Yellow Card Scheme.1

If you notice any symptoms that might be indicative of an allergic reaction, you should immediately seek medical help. The usual symptoms include:

  • Hives
  • Swelling of the face, lips or throat
  • Seizures

Other side effects documented so far include:

Frequency of occurrence Side effects
Very common (more than 1 in 10 users) Nausea, vomiting, pain in the abdomen, constipation, headache, difficulty sleeping, anxiety, agitation, pain in the joints and muscles
Common (less than 1 in 10 users) Low white blood cell count, dizziness, vertigo, tremor, irritability, depression, mood disorders, fever, diarrhoea, change in the taste of food, tinnitus, fast heartbeat
Uncommon (less than 1 in 100 users) Cold sores, athlete’s foot, swollen glands in the neck, armpit or groin, dehydration, increased appetite, weight gain, abnormal dreams, loss of libido, mental health issues
Rare (less than 1 in 1000 users) Unexplained bleeding or bruising under the skin, blood sugar fluctuation, irritability, aggressiveness, suicidal thoughts and behaviour, sense of unreality of surroundings
Very rare (less than 1 in 10.000 users) Angioedema, severe allergic reaction, delusions, aggression, muscle and kidney problems

Please keep in mind that this is far from the complete list of side effects – for a more comprehensive overview, please refer to the official patient information leaflet. Even there, you will find all the side effects documented so far. As the medication is still monitored, there might be other side effects which have not been discovered so far.

Is Mysimba safe for me?

As is the case with all prescription medications, not everybody is suitable for them. The same is true for Mysimba. And there are several scenarios where the use of Mysimba might be contraindicated. For starters, you should not be using this medication if you are currently taking any of the following:

  • Monoamine oxidase inhibitors (MAOI)
  • Opiates or opiate-containing medicines
  • Naltrexone
  • Bupropion-containing medicines
  • Antidepressants
  • Steroids
  • Antimalarials
  • Medicines for lowering sugar levels
  • Hypertension medications
  • Cancer treatments

In addition to this, there are also certain medical conditions that might make you unfit for Mysimba treatment. These include:

  • Abnormally high blood pressure
  • Alcoholism
  • Brain tumour
  • Mental health problems
  • Eating disorders
  • Opiates dependency
  • Opiates withdrawal
  • Severe kidney or liver conditions
  • Suicidal behaviour
  • Head trauma
  • Drug addiction
  • Uncontrolled coronary artery disease

Extra caution is also advised for those aged 65 and over when using this medication. Finally, it is not suitable for women who are trying to conceive, are pregnant or are currently breastfeeding.


  1. Yellow Card Scheme – UK