Wegovy (semaglutide) in the Treatment of Obesity

How does Wegovy (semaglutide) work in the body?

Wegovy works through the active substance semaglutide mimicking the effect of the body's natural satiety hormone GLP-1 (glucagon-like peptide-1). This hormone is part of the body's physiological system for appetite regulation and signals to the brain that energy has been supplied, which contributes to an increased feeling of fullness and reduced food intake.

Upon food intake, GLP-1 is normally released from the small intestine, but the hormone has a very short half-life and is rapidly broken down by enzymes in the body. Semaglutide is structurally modified to resist this breakdown, providing a more long-lasting activation of GLP-1 receptors.

The treatment thus affects several central and peripheral mechanisms involved in appetite and energy balance. This leads to reduced hunger, increased satiety, and a reduced spontaneous energy intake.

For many patients, this means it becomes easier to maintain an energy deficit over time, which is a prerequisite for weight loss. The effect does not arise by replacing lifestyle changes, but by facilitating the implementation of them.

Food stays in the stomach longer

Wegovy affects the gastrointestinal tract by delaying gastric emptying. This means that food stays in the stomach longer, which contributes to a more long-lasting and pronounced feeling of fullness after a meal.

This effect has several clinically relevant consequences. Delayed gastric emptying can contribute to a reduced energy intake by reducing the tendency to snack between meals.

The treatment also stimulates insulin release at elevated blood sugar levels and inhibits glucagon production, which contributes to more stable blood sugar levels. This effect is particularly relevant for people with impaired blood sugar regulation, such as in type 2 diabetes or insulin resistance, where a more stable blood sugar profile is an important part of the treatment.

How Wegovy (injectable solution) is administered

Wegovy is administered as a subcutaneous injection once per week using a pre-filled injection pen. The injection is given superficially into the subcutaneous fat, usually in the abdomen or thigh.

It is common to feel some uncertainty about giving oneself an injection, especially at the beginning of treatment. However, the injection pen is designed to be simple and safe to use at home, even without prior experience with injections.

The needle is very short and thin, which means most people experience the prick as mild or barely noticeable.

To ensure a consistent and stable level of medication in the body, it is recommended that the injection be taken on the same day every week.

Dosage and escalation

Treatment begins with a low starting dose of 0.25 mg and is subsequently stepped up gradually, usually at approximately four-week intervals. This is done so the body can gradually adapt to the treatment and to improve tolerability.

A stepwise dose increase is an important part of the treatment and contributes to reducing the risk of gastrointestinal side effects.

In clinical practice, the principle of the lowest effective dose is often applied. This means the dose can be individually adapted based on treatment response and tolerance. If a patient achieves a good effect on a lower dose, such as 1.0 mg or 1.7 mg, it may be appropriate to remain at that level.

The treatment is followed up and adjusted continuously by the treating physician based on medical results, side effects, and individual circumstances.

Wegovy compared to other medications

Wegovy and Ozempic are both manufactured by the pharmaceutical company Novo Nordisk and contain the same active substance, semaglutide. Ozempic was originally developed and approved for the treatment of type 2 diabetes, usually in lower doses than those used in obesity treatment.

Wegovy is specifically developed and approved for the treatment of obesity and overweight with weight-related complications. The approval is based on extensive clinical studies, including the so-called STEP program, where the effect on weight loss has been evaluated. Wegovy is used in doses adapted for weight treatment.

Prescribing Ozempic solely for the purpose of treating overweight in people without type 2 diabetes constitutes off-label use. Such prescription may occur after an individual medical assessment, but in clinical practice, medications specifically approved for obesity are primarily used when these are available.

Mounjaro, manufactured by Eli Lilly, contains the active substance tirzepatide. Unlike semaglutide, tirzepatide is a so-called dual agonist that activates both GLP-1 and GIP receptors. In clinical studies, this has shown a significant effect on weight loss, and in some studies, a greater average weight reduction compared to semaglutide.

For more information on different treatment options, you can read further here.

What results can one expect from the treatment?

In clinical studies, patients treated with semaglutide (Wegovy) achieved on average a weight loss of approximately 15 percent of their original body weight after about 68 weeks of treatment.

These results are based, among other things, on the STEP 1 study, where participants were treated with 2.4 mg semaglutide once per week in combination with support regarding diet and physical activity. However, individual treatment response varies between different patients.

In addition to weight loss, studies have also shown improvements in several cardiometabolic risk factors, such as blood pressure, blood lipids, and waist circumference. Such changes are associated with a reduced risk of cardiovascular disease over time.

Who can be prescribed Wegovy for weight loss?

Medications for medical weight loss, such as Wegovy, can be considered for adults with a BMI of 30 or higher, or for people with a BMI of at least 27 in combination with at least one weight-related disease, such as type 2 diabetes, high blood pressure, obstructive sleep apnea, or dyslipidemia.

These threshold values are based on established medical guidelines, where obesity is classified as a chronic disease with an increased risk of long-term health complications. The treatment is not intended for cosmetic weight loss, but aims to improve metabolic health and reduce the risk of secondary diseases, especially cardiovascular conditions.

Before starting treatment, an individual medical assessment is always performed by a licensed physician. This includes a review of medical history, previous weight loss attempts, and relevant laboratory tests, such as thyroid status, blood sugar (HbA1c), and liver values, to ensure the treatment is appropriate and safe. It is not just about "getting approved" for treatment, but about creating a safe medical baseline. Tests such as blood sugar, blood lipids, and liver values can show both the risk level and what improvements occur during treatment.

You can delve deeper into how the medical investigation and prescription process for GLP-1 medications works in our detailed guide.

What do I do if I feel nauseous from Wegovy?

Nausea is one of the most common side effects of treatment with Wegovy, especially at the beginning of treatment or in connection with a dose increase. The discomfort is usually mild to moderate and generally subsides as the body adapts.

You can often alleviate the symptoms through simple adjustments in your eating habits. Eating smaller portions, chewing food thoroughly, and eating at a calm pace can reduce the load on the stomach. It can also be helpful to limit the intake of fatty, fried, or highly spiced food, as such a diet can exacerbate nausea for some people.

Semaglutide affects the gastrointestinal tract by delaying gastric emptying, which means food stays in the stomach longer. If portion sizes are not adapted, this can contribute to increased discomfort, including nausea.

To prevent constipation, which can also occur, it is important to ensure sufficient fluid intake and to keep the bowel function going through regular physical activity.

If the discomfort is pronounced or persists over time, you should contact your treating healthcare provider for further advice.

Preserve muscle mass during your weight loss

To preserve muscle mass during weight loss, it is important to combine the treatment with a sufficient protein intake and regular strength training.

Wegovy contributes to a reduced energy intake, and for weight loss, the body needs to be in a so-called energy deficit. In such a state, the body uses both fat and muscle tissue as an energy source. Without sufficient stimulus and nutrition, part of the weight loss may therefore consist of loss of muscle mass.

An adequate protein intake provides the building blocks required to preserve muscle tissue, while strength training works as a signal to the body that the muscles are needed. Together, this contributes to a more favorable body composition, where a larger proportion of the weight loss consists of fat mass.

Preserved muscle mass also has significance for the basal energy expenditure (resting metabolic rate). A larger loss of muscle mass can contribute to lower energy expenditure over time, which in some cases can make it more challenging to maintain the weight loss.

What happens when you stop using Wegovy?

When treatment with Wegovy is discontinued, the medication's effect on appetite regulation and satiety ceases. This means that hunger and cravings can gradually return to levels similar to those before the start of treatment, which can make it harder to maintain a lower energy intake.

Since obesity is a chronic disease with biological drivers, there is an increased risk of weight regain after stopping treatment. Long-term follow-ups from clinical studies have shown that a significant part of the weight loss achieved is often regained over time, especially if the treatment is not combined with established lifestyle habits.

This underlines that obesity treatment in many cases needs to have a long-term perspective. For some patients, continued treatment or a maintenance dose may be relevant to maintain the results. The treatment strategy is always adapted individually in consultation with the treating physician.

Want to know more? Read our in-depth article on how the body is affected after treatment is discontinued.

Frequently asked questions about Wegovy

How long must one take Wegovy to see results?

Many patients experience reduced appetite already during the first weeks of treatment. Visible weight loss usually occurs gradually and often becomes more apparent after a few months, as the dose is stepped up to an effective treatment level. It is important to remember that treatment response varies between individuals. For best results, it is recommended that the treatment be combined with adapted dietary habits and regular physical activity.

What happens if I miss my dose of Wegovy one week?

If you miss a dose of Wegovy, you can take it as soon as you remember it, provided there are at least 48 hours left until your next planned injection. If there are less than 48 hours left until the next dose, you should skip the missed dose and continue according to your regular dosing schedule. You should not take a double dose to compensate for a missed injection, as this can increase the risk of side effects without improving the effect.

What should one eat to not feel nauseous from Wegovy?

To alleviate nausea, it can be helpful to eat smaller, regular meals that are gentle on the stomach. Many find that protein-rich foods in small portions work better than larger meals. It can also be good to limit the intake of fatty, fried, or highly spiced food, as such a diet can be harder to digest and exacerbate nausea for some people. Since Wegovy delays gastric emptying, food stays in the stomach longer, which means that large or heavy meals can contribute to increased discomfort. Eating slowly and ending the meal at early satiety signals can therefore reduce the discomfort.

How long does a pre-filled pen (FlexTouch) with Wegovy from Novo Nordisk last?

An unopened Wegovy pen should always be stored in a refrigerator (2–8 °C) until its expiration date. If the pen is taken on a trip, it can often be stored at room temperature (maximum 30 °C) for a limited time, usually up to 6 weeks. Always read the enclosed package leaflet for complete and current instructions.

Sources

Wilding JPH et al. (STEP 1 Trial). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England Journal of Medicine. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183

Wilding JPH et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, Obesity and Metabolism. https://pubmed.ncbi.nlm.nih.gov/35441470/

Rubino D et al. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. JAMA. https://jamanetwork.com/journals/jama/fullarticle/2777886

European Medicines Agency (EMA). Wegovy (semaglutid) – EPAR Product Information. https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy

Prado CM et al. Muscle matters: the effects of medically induced weight loss on skeletal muscle. The Lancet Diabetes & Endocrinology. https://pubmed.ncbi.nlm.nih.gov/39265590/