Mysimba and orlistat are two prescription weight management medicines used in the UK, but they work in very different ways. Choosing between them depends on your medical history, the treatment that is suitable for you, possible side effects, cost and what you can manage alongside diet and physical activity.
Mysimba vs orlistat, mysimba or orlistat, which is better mysimba or orlistat and difference between mysimba and orlistat are all asking a similar question. There is no single answer for everyone. Mysimba works on areas of the brain involved in controlling food intake, while orlistat reduces the amount of dietary fat absorbed in the gut.
This guide compares them by how they work, who may be able to take them, expected results, side effects, cost and UK availability. It also looks at the question of taking both medicines together. Can you take Mysimba and orlistat together? They are not a licensed combination, and there is no established evidence that using both provides additional weight loss.
Key things to know
- Mysimba contains naltrexone and bupropion and works on areas of the brain involved in controlling food intake and energy expenditure.
- Orlistat works in the digestive system by reducing the absorption of dietary fat. It does not directly reduce hunger or food cravings.
- The price of either medicine can vary between providers, and the total cost may include consultation, prescription and delivery fees.
- Mysimba has more contraindications and safety precautions than orlistat.
- Both are prescription only medicines and require an appropriate assessment before prescribing.
- Both should be used alongside a reduced calorie diet and increased physical activity.
Quick Answers
| The question | The answer |
|---|---|
| Which is better, Mysimba or orlistat? | Neither is automatically better. They work differently, so suitability depends on your health, treatment needs and medical history. |
| Which is cheaper? | Prices vary between providers. Orlistat is often available at a lower cost, but check the full price, including any consultation or delivery fees. |
| Can you take them together? | They are not a licensed combination. If someone is considering both, a prescriber should assess whether there is a specific reason to use them together. |
| Which works faster? | Orlistat starts affecting fat digestion within 24 to 48 hours, but that does not mean you will see meaningful weight loss in a few days. Weight changes take longer. |
| Which has fewer restrictions? | Orlistat has fewer contraindications than Mysimba, although it still has important medicine interactions and restrictions. |
| What is the 16 week rule? | Mysimba should be discontinued after 16 weeks if at least 5 per cent of initial body weight has not been lost. |
How Each One Works
How does Mysimba work and how does orlistat work have very different answers. That difference is important when discussing which treatment may be suitable.
Mysimba combines naltrexone and bupropion. These medicines act on areas of the brain involved in controlling food intake and energy expenditure. The aim is to support weight management alongside a reduced calorie diet and increased physical activity.
The dose is gradually increased over the first four weeks. From week 4 onwards, the maximum recommended dose is two tablets in the morning and two in the evening, for a total of four tablets a day. Mysimba is a prescription only medicine.
Mysimba is not normally available on the NHS for treating overweight or obesity because NICE did not recommend it as a cost effective treatment for routine NHS use. It can still be prescribed privately when a prescriber considers it appropriate.
Orlistat works very differently. It inhibits enzymes called gastrointestinal lipases, which normally break down dietary fat so that it can be absorbed. By blocking these enzymes, orlistat reduces the amount of fat absorbed from food. Some of the unabsorbed fat then passes out in the stools.
Orlistat does not directly reduce hunger or food cravings. Prescription orlistat 120mg is normally taken with each main meal that contains fat. If a meal is missed or contains no fat, the dose should be omitted. Following the recommended lower fat diet can also help reduce digestive side effects.
Orlistat is recommended by NICE as an option for weight management when the relevant criteria are met.
So naltrexone, bupropion and orlistat together, and Contrave and orlistat together, describe a combination of a medicine that acts on the brain with one that acts mainly in the gut. Contrave is the brand name used for the naltrexone and bupropion combination in some countries outside the UK.
There is no licensed indication for routinely combining Mysimba with orlistat, and there is no established clinical evidence showing that the combination provides additional weight loss. If someone is considering both, that decision should be made by a prescriber rather than by adding one medicine to another themselves.
Both medicines are intended to be used alongside lifestyle changes. Your prescriber should review your medical history, current medicines and relevant health conditions before treatment begins.
Side by Side
| Mysimba | Orlistat | |
|---|---|---|
| Contains | Naltrexone and bupropion | Orlistat |
| Acts on | Areas of the brain involved in appetite and food intake | Fat digestion in the gut |
| Format | Prolonged release tablet, with the dose built up over four weeks | Capsule taken with each fat containing meal |
| Trial weight loss | Results varied between studies. In 56 week trials, average weight loss was higher with Mysimba than placebo | In the XENDOS trial, the mean difference in weight loss between orlistat and placebo was 2.7kg after 4 years |
| Review point | 16 weeks against a 5 per cent weight loss threshold | 12 weeks against a 5 per cent weight loss threshold |
| Main side effects | Nausea, constipation, headache, insomnia and dry mouth | Oily or loose stools, urgency, wind and oily spotting |
| Monitoring | Blood pressure, heart rate and treatment response, with attention to mood and other safety concerns | No equivalent routine blood pressure and heart rate monitoring, but medicine interactions and treatment response still need review |
| Relative cost | Prices vary between providers | Prices vary between providers and may be lower than Mysimba in some services |
These figures come from clinical trials and should not be treated as a prediction of what one person will lose. Results can vary depending on the study, the person, the length of treatment and the lifestyle changes made alongside the medicine.
Who Can and Cannot Take Each
Suitability is often decided by medical history before cost or preference comes into the picture. Both medicines have specific criteria and reasons why they may not be suitable.
Who cannot take Mysimba
Mysimba has a relatively long list of contraindications and safety precautions. These include:
- Uncontrolled high blood pressure, because Mysimba can increase blood pressure and heart rate.
- A current seizure disorder or a history of seizures.
- A known central nervous system tumour.
- Acute withdrawal from alcohol or benzodiazepines.
- A history of bipolar disorder.
- Current treatment with another medicine containing bupropion or naltrexone.
- A current or previous diagnosis of bulimia or anorexia nervosa.
- Current opioid dependence or acute opioid withdrawal.
- Treatment with monoamine oxidase inhibitors (MAOIs), or use of an MAOI within the previous 14 days.
- Severe liver impairment.
- End stage renal failure.
- Pregnancy.
- An allergy to naltrexone, bupropion or any of the other ingredients.
There are also age related precautions. Mysimba should be used with caution in people over 65 and is not recommended for people over 75.
Anyone taking another medicine containing bupropion or naltrexone should tell their prescriber before starting Mysimba.
Who cannot take orlistat
Orlistat has fewer contraindications, but it still is not suitable for everyone.
These include:
- Pregnancy.
- Breastfeeding.
- Chronic malabsorption syndrome, which affects the body's ability to absorb nutrients.
- Cholestasis, a condition where the flow of bile from the liver is reduced or blocked.
Orlistat can also interact with several medicines. Particular care may be needed if you take medicines such as ciclosporin, levothyroxine, warfarin or other oral anticoagulants, some antiepileptic medicines, amiodarone or certain HIV medicines.
Both medicines have BMI criteria for their licensed use in weight management.
Mysimba is indicated for adults with an initial BMI of 30 kg/m² or more, or a BMI from 27 kg/m² to under 30 kg/m² when there is at least one weight related condition, such as type 2 diabetes, dyslipidaemia or controlled hypertension.
Prescription orlistat 120mg is indicated for adults with a BMI of 30 kg/m² or more, or a BMI of 28 kg/m² or more with associated risk factors.
Orlistat should be used with a mildly hypocaloric diet containing about 30 per cent of calories from fat. Eating a very high fat meal can make digestive side effects more noticeable.
Regular physical activity is also part of weight management with both medicines.
Results You Can Reasonably Expect
How much weight can you lose on Mysimba and how much weight can you lose on orlistat are better answered using clinical trial data rather than promises.
In 56 week clinical trials, Mysimba produced different results across studies. For example, one trial reported a mean reduction of 5.4 per cent with Mysimba compared with 1.3 per cent with placebo. Another reported 8.1 per cent compared with 1.8 per cent among people who completed treatment.
Orlistat has also produced additional weight loss compared with placebo in long term studies. In the 4 year XENDOS trial, the mean difference between orlistat and placebo was 2.7kg.
These numbers come from groups of people in clinical studies. They do not mean that everyone taking the medicine will lose the same amount.
It is also important to remember that both medicines are used alongside dietary and lifestyle changes. The results cannot be treated as the effect of the tablet alone.
The review points, and why they matter
The Mysimba 16 week stopping rule is part of its UK marketing authorisation. Treatment should be discontinued after 16 weeks if at least 5 per cent of initial body weight has not been lost.
The need for continued Mysimba treatment should then be reviewed regularly, including an annual review.
Orlistat has a 12 week stopping point. Treatment should be discontinued after 12 weeks if at least 5 per cent of initial body weight has not been lost.
For someone starting at 100kg, 5 per cent is 5kg. The figure gives the prescriber an objective point to review whether treatment is providing enough benefit to continue.
Side Effects Compared
Mysimba side effects UK and orlistat side effects UK are quite different because the medicines work in different parts of the body.
Common side effects with Mysimba include nausea, constipation, headache, difficulty sleeping, dizziness and dry mouth. Nausea is particularly common during the first few weeks while the dose is being increased.
Mysimba can also increase blood pressure and heart rate in some people. Blood pressure and heart rate should therefore be checked before treatment and monitored during treatment.
The product information also includes warnings about psychiatric and neuropsychiatric effects, including suicidal thoughts and behaviour. If your mood changes significantly or you develop thoughts of self harm, seek medical advice promptly.
Orlistat's side effects are mainly digestive. These can include oily or loose stools, an urgent need to open your bowels, wind and oily spotting. They are more likely to be troublesome after meals that are high in fat.
Cost and Value
Mysimba lowest price UK, cheapest Mysimba UK, Mysimba price UK, cheapest orlistat UK, orlistat 120mg price UK, cheapest weight loss tablets UK and cost of taking Mysimba and orlistat together all come back to the same practical question: what will the treatment actually cost you?
There is no single UK price for either medicine. Private providers can set different prices, and the total cost may include a consultation, prescription, medicine, delivery or follow up fee.
Orlistat is often available at a lower price than Mysimba, but the actual difference depends on the provider and treatment plan. So it is better to compare the complete cost rather than looking only at the medicine price.
Four checks can make the comparison more useful:
- Look at the standard price: An introductory discount may only apply to the first order.
- Check every fee: Include consultation, prescription, review, delivery and any express delivery charges.
- Look at the treatment period: Mysimba has a 16 week review point, while orlistat has a 12 week review point.
- Consider how much orlistat you actually use: A dose is omitted when a meal contains no fat or when a meal is skipped.
As for the cost of taking Mysimba and orlistat together, there is no established evidence that using both provides additional weight loss. A prescriber would therefore need a clear clinical reason before considering such a combination.
Can You Take Mysimba and Orlistat Together?
Is it safe to take Mysimba and orlistat together, Mysimba and orlistat together UK and Mysimba orlistat interaction all lead to an important distinction.
There is no established clinically significant interaction between the two medicines in their UK product information. However, they are not a licensed combination, and the absence of a known interaction does not prove that using both together is safe or beneficial.
There are several reasons why a prescriber would need to think carefully about the combination:
- There is no established evidence of additional weight loss. The two medicines have not been established as a routine combined treatment.
- You would be exposed to the side effects of both medicines. Mysimba can cause nausea and constipation, while orlistat commonly causes loose or oily stools and urgency.
- Their review points are different. Mysimba has a 16 week stopping rule, while orlistat has a 12 week stopping point.
- The treatment becomes more complicated. It can be harder to work out which medicine is responsible for a side effect or change in symptoms.
- The overall cost would increase. There is no established additional benefit to justify routinely paying for both.
How long should I wait between Mysimba and orlistat, can you take Mysimba and orlistat at the same time and best time to take Mysimba and orlistat do not have an established UK dosing schedule for combination use.
If a prescriber does consider using both, follow their specific instructions rather than relying on a timing schedule found online.
How To Choose
A useful way to approach the decision is to look at what you need from treatment and, just as importantly, what may make one medicine unsuitable.
| Your situation | What to discuss with your prescriber |
|---|---|
| Appetite and food intake are major concerns | Whether Mysimba is clinically appropriate |
| You are looking for a medicine that works in the gut | Whether orlistat is suitable |
| Cost is an important consideration | Compare the complete cost of each treatment, including consultation and follow up fees |
| You have a history of seizures, opioid use, an eating disorder or bipolar disorder | Mysimba may not be suitable, so discuss other options |
| You take several regular medicines | Check for interactions before choosing either medicine |
| You are looking at medicines beyond tablets | Ask about the wider range of weight management treatments available |
This table is not a self assessment tool. Your prescriber may reach a different conclusion after looking at your full medical history, current medicines and treatment goals.
Suitability can be discussed at a weight loss consultation, and it can also be useful to compare weight loss treatment options rather than focusing on only two medicines.
Buying Either One in the UK
Buy Mysimba online UK and weight loss tablets UK searches raise an important question: what should a legitimate online service look like?
Mysimba is a prescription only medicine. An online service should require an appropriate clinical assessment before a prescriber decides whether to issue a prescription. The assessment should cover relevant medical history, current medicines, BMI and important safety questions.
Mysimba is not normally available on the NHS for managing overweight or obesity. NICE states that it is not normally available on the NHS for this purpose.
Prescription orlistat 120mg can be prescribed when the relevant criteria are met. Orlistat 60mg is also available from pharmacies as a pharmacy medicine for adults with a BMI of 28 kg/m² or more, subject to a pharmacist's assessment.
If you are buying either medicine online, check that the pharmacy is registered with the General Pharmaceutical Council and that the service explains who is responsible for the clinical assessment and prescription.
