Mysimba for Weight Loss

What is Mysimba?

Mysimba is a combination medication containing two active ingredients: naltrexone (an opioid antagonist) and bupropion (an atypical antidepressant also used to help quit smoking). This unique combination has been EU-approved since 2015 for weight management and is taken as a tablet, not as an injection.

Unlike GLP-1 medications such as Ozempic, Mysimba does not work via the gut hormone GLP-1 but rather through the reward system and the brain's hunger center. This makes it particularly effective for people with emotional eating, strong cravings for sweets and snacks, and repeated binge eating episodes. In clinical studies, users achieved an average of 5–8% weight loss.

Mysimba is especially suitable if you prefer taking a tablet rather than injections, or if you have previous experience with bupropion (for depression or smoking cessation).

How Does Mysimba Work?

The two active ingredients in Mysimba work together on a synergistic system. Naltrexone blocks opioid receptors in your reward system, reducing the pleasure you derive from eating and decreasing your cravings for sugar and fat. This part of your brain is involved in impulsive eating and binge episodes.

Bupropion, on the other hand, activates POMC neurons (pro-opiomelanocortin neurons) in the hypothalamus, your brain's hunger center. This suppresses hunger and reduces appetite in a direct, biological manner. Bupropion also increases energy levels, which can help with motivation for physical activity.

Together, these substances work at multiple levels: reducing hunger, lowering cravings, reducing the 'reward value' of food, and decreasing emotional eating. This is very different from GLP-1 medications, which work primarily through satiety.

Dosage & Titration Schedule

Mysimba is titrated according to a fixed schedule to minimize side effects and allow your body to adjust to the medication.

Each Mysimba tablet contains 8 mg naltrexone hydrochloride and 90 mg bupropion hydrochloride.

Clinical Results (COR Studies)

The efficacy of Mysimba has been investigated in a series of large, randomized trials known as the COR studies (Contrave Obesity Research). Participants using Mysimba achieved an average weight loss of 5–8% after 56 weeks of treatment.

• 42% of participants achieved ≥5% weight loss
• 20% achieved ≥10% weight loss
• Improvement in waist circumference and body fat percentage (no muscle loss)
• Favorable changes in triglycerides and insulin resistance
• In the COR-BMOD study: additional benefit with intensive behavioral modification

Weight loss is individual and depends on adherence to the schedule, lifestyle changes, and metabolism.

Storing Mysimba

Missed Dose

If you forget a dose:

Side Effects

Very common (>10%)

• Nausea (33% in first weeks, usually subsides)
• Constipation
• Headache
• Vomiting

Common (1–10%)

• Dizziness
• Dry mouth
• Insomnia or restlessness
• Anxiety or nervousness
• Abdominal pain or gastrointestinal discomfort
• Elevated blood pressure
• Hot flashes
• Muscle aches or cramps
• Heart palpitations
• Increased heart rate

Serious (contact your physician)

• Seizures (rare, especially at higher doses)
• Severe allergic reaction (swelling of face/lips/tongue, difficulty breathing)
• Sudden elevated blood pressure (hypertensive crisis)
• Suicidal thoughts or mood changes (very rare, close monitoring required for those with history)
• Psychosis or hallucinations (very rare)

Tips to minimize side effects

• Take tablets in the morning and evening with food (breakfast and dinner) to prevent nausea and insomnia
• Strictly follow the titration schedule, do not skip weeks
• Drink plenty of water (at least 2 liters per day) to prevent constipation
• Eat plenty of fiber: vegetables, fruits, whole grains, nuts
• Avoid fatty and spicy foods in the first weeks
• Ensure regular physical activity (also helps with constipation)
• Get sufficient sleep (7–9 hours per night) for mental health
• Report any unusual mood or behavioral changes to your physician immediately

Contraindications

Mysimba should not be used or requires caution in the following situations:

• Uncontrolled high blood pressure (systolic >160 mmHg or diastolic >100 mmHg)
• Epilepsy or increased risk of seizures (including abrupt cessation of sedatives)
• Current or recent eating disorder (anorexia nervosa, bulimia nervosa)
• Use of MAOIs (certain antidepressants) or discontinued within 14 days
• Abrupt discontinuation of alcohol, benzodiazepines, or barbiturates (seizure risk)
• Severe liver or kidney problems
• Bipolar disorder (increased risk of manic episodes with bupropion)
• Pregnancy or breastfeeding
• Under 18 years of age
• Concurrent use of other bupropion-containing medications
• Concurrent use of opioids (analgesic effect is lost, overdose risk)
• Allergy to naltrexone, bupropion, or excipients

Difference from GLP-1 Medication (Ozempic, Wegovy, Mounjaro)

Mysimba and GLP-1 medications work in very different ways. Here is a practical comparison:

Some patients lose weight better with Mysimba because their weight problem is more related to emotional eating and cravings. Others respond better to GLP-1. Your physician will help determine which option is best for you.

Insurance & Reimbursement

Mysimba is unfortunately not standard covered by Dutch health insurers. However:

• Consult your health insurer or supplementary insurance for possible coverage
• Some patients have success submitting a request for exceptional reimbursement
• Go Leaner offers transparent pricing with no surprises

Composition

Mysimba at Go Leaner

Mysimba is part of our integrated treatment program. You don't just get a prescription: you work with a board-registered physician who monitors your dosage, receive guidance from a lifestyle coach for nutrition and exercise, and are evaluated monthly. Mysimba is especially suitable if you prefer a tablet over injections, or if emotional eating and cravings are your biggest obstacles.

View our protocol →

Frequently Asked Questions