Effect of bupropion hydrochloride and mushroom supplement on body weight in overweight adults: a 52‑week randomized trial

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What is this study about?

The trial focuses on adults who are overweight or have obesity classified as class I, meaning a BMI between 25.0 and 34.9 kg/m². Many participants also show signs of hypertension, hyperlipidemia, or prediabetes, conditions that together increase cardiometabolic risk. Three approaches are being tested: a structured program of diet and exercise changes, a daily dose of mushroom supplementation, and the oral medication bupropion taken at a standard dose.

The main aim of the study is to compare how each approach affects body weight after six months.

Participants will be assigned by chance to one of the treatment groups and will follow the assigned plan for up to one year. Throughout the study, regular visits will be scheduled to record weight, check blood pressure, cholesterol levels, and blood sugar, and to monitor any side effects. The study does not involve any invasive procedures, and all information is collected in a routine clinical setting.

1 enrollment and consent

after agreeing to join the study, you will sign a consent form that explains the purpose of the trial and what is expected of you.

2 baseline assessment

the study team will measure your weight, height, blood pressure, and may take blood samples to check cholesterol and blood sugar levels.

these measurements create a starting point to compare changes during the trial.

3 random assignment to a treatment group

you will be placed at random into one of three groups: a lifestyle‑change group, a mushroom‑supplement group, or a bupropion medication group.

random assignment means the group is chosen by chance, not by personal choice.

4 starting the assigned intervention

if you are assigned to the bupropion group, you will take one tablet containing 300 mg of bupropion hydrochloride by mouth each day.

the medication is taken once daily for the entire 52‑week study period.

if you are assigned to the lifestyle‑change group, you will receive guidance on diet, physical activity, and behavior strategies to help reduce weight.

if you are assigned to the mushroom‑supplement group, you will receive the supplement according to the instructions provided by the study team.

5 regular follow‑up visits

you will return to the clinic at scheduled times to check your weight, blood pressure, and any side effects.

common visit times are at 4 weeks, 12 weeks, 24 weeks (6 months), 36 weeks, and at the end of the study at 52 weeks.

6 primary outcome assessment at 6 months

at the 24‑week visit, the team will calculate the percent change in your body weight compared with the baseline measurement.

this measurement is the main result the study is looking at.

7 final assessment at 52 weeks

at the last visit, after 52 weeks, you will undergo the same measurements as at baseline and at 6 months.

the final data will show how your weight and health markers changed over the full year of the trial.

Who Can Join the Study?

Be a man or a woman who is between 18 and 55 years old.
Have a body‑mass index (BMI) between 25.0 and 34.9 (this means being overweight or having mild obesity).
Sign a written informed consent form, which shows you understand the study and agree to take part.
Own a mobile phone, tablet, or computer that can connect to the internet.
Fit into one of the two groups for cardiometabolic risk factors:
- Either have none of the following conditions: high blood pressure (hypertension), high blood fats or cholesterol (hyperlipidemia), or prediabetes (higher than normal blood sugar but not diabetes).
- Or have one or more of those conditions: hypertension, hyperlipidemia, or prediabetes.

Who Cannot Join the Study?

Food intolerances or allergies that matter for the study, such as celiac disease (a reaction to gluten) or an allergy to edible mushrooms or fungal spores.
If you have a medical reason that makes taking the medicine bupropion unsafe, or if the doctor thinks the treatment could be risky for you.
If you are currently following, or have recently (within the past 3 months) followed, a low‑calorie diet, are taking weight‑loss medicines, or have lost more than 3 kg (about 6‑7 lb) in the past three months.
If you have been diagnosed with any serious health problems such as diabetes, coronary heart disease (heart disease caused by blocked arteries), heart failure, stroke, liver failure, or kidney disease (kidney function measured as eGFR < 60 ml/min/1.73 m²), or any other serious illness that shortens life expectancy or would make study participation difficult.
If you have taken any of the following medicines within the recent time frames: other products that contain bupropion (within the past 2 weeks); other weight‑loss drugs such as orlistat, phentermine‑topiramate, SGLT2 inhibitors, or GLP‑1 receptor agonists (within the past 3 months); certain antidepressant or antipsychotic medicines including antipsychotics, mirtazapine, tricyclic antidepressants, or serotonin‑norepinephrine reuptake inhibitors (within the past 3 months); MAOIs (a type of antidepressant) (within the past 2 weeks); systemic glucocorticoids (steroid medicines that affect the whole body) (within the past 3 months); testosterone or anabolic steroids (muscle‑building hormones) (within the past 6 months); any medicines that are broken down by the liver enzyme CYP2D6; or any medicines that affect the liver enzyme CYP2B6.
If you are currently pregnant or plan to become pregnant during the study period.

Where you can join this trial?

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Site Name	City	Country
Region Uppsala	Uppsala	Sweden
Vaestra Goetalandsregionen	Vänersborg	Sweden
Uwijzbp Uufenpcywm Hxnhkscj	Uppsala	Sweden

Trial status

Country	Status	Recruitment Start
Sweden	Not yet recruiting	01.10.2026

Trial locations

Investigated Drugs:

Bupropion Hydrochloride

The trial includes a program of lifestyle changes, where participants receive guidance on healthy eating, regular physical activity, and behavior strategies to help them lose weight and improve heart health. This approach aims to teach people how to make lasting habits that can reduce body fat and lower the risk of diabetes and other metabolic problems.

Another part of the study tests a mushroom supplement. Participants take a product made from specific edible mushrooms that are believed to have natural compounds which may help manage weight and support metabolic function. The supplement is given in addition to the other interventions to see if it adds any extra benefit.

The medication tested in the trial is bupropion. This is an oral drug that works on brain chemicals to help reduce appetite and increase energy use, which can lead to weight loss. In the study, it is used together with the other approaches to see how well it helps participants lose weight and improve their cardiometabolic health.

Investigated Diseases:

Overweight or class I obesity – a condition where body weight is higher than normal but not extreme, defined by a body‑mass index between 25.0 and 34.9 kg/m². Excess weight gradually accumulates when calorie intake exceeds energy use, leading to increased fat stores. Over time, the extra fat can expand around the abdomen and other areas, making the person heavier. The condition may remain stable, improve, or worsen depending on lifestyle and metabolic factors. It can develop slowly over months to years.
Hypertension – a condition characterized by consistently high blood pressure in the arteries. Blood pressure rises when the heart pumps blood with more force or when the vessels are stiff. Over time, the pressure can increase further if underlying causes are not addressed. The elevated pressure may persist and can lead to changes in the heart and blood vessels. It often develops gradually and may be silent for many years.
Hyperlipidemia – a disorder where the blood contains high levels of lipids such as cholesterol and triglycerides. Lipid levels rise when the body produces too much or clears them too slowly. The excess lipids can accumulate on artery walls, thickening them over time. The condition can stay unchanged, improve, or worsen depending on diet and genetics. It usually progresses silently over years.
Prediabetes – a state in which blood sugar levels are higher than normal but not high enough for a diabetes diagnosis. The body’s ability to use insulin becomes less efficient, causing glucose to linger in the bloodstream. If the imbalance continues, glucose levels may rise further. The condition can remain stable, revert to normal, or advance to type 2 diabetes. It often develops gradually and may have few obvious symptoms.

Trial ID:

2026-527136-13-00

Protocol code:

IMPETUS-2026

Trial Phase:

Therapeutic confirmatory (Phase III)

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Effect of bupropion hydrochloride and mushroom supplement on body weight in overweight adults: a 52‑week randomized trial

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