Key takeaways

  • It’s unlikely that you’ll see noticeable weight changes in the first week of Wegovy. But your doctor might observe improvements in your blood pressure or blood sugar levels.
  • You could experience side effects such as nausea, diarrhea, or constipation in the first week. You might experience some of these or other side effects in later weeks of treatment.
  • With Wegovy treatment, you may notice differences in how you feel about food (appetite, cravings, choices). These may help you lose weight. If you take Wegovy for metabolic dysfunction-associated steatohepatitis (MASH), you may have less fatigue, reduced pain, and improvement in skin color.

Wegovy (semaglutide) is approved by the Food and Drug Administration (FDA) for weight management in certain people who are overweight or have obesity. It’s a once-weekly injection. (This article explains calculating body mass index [BMI], which is used to define “overweight” and “obesity.”) People with overweight also must have at least one weight-related condition, such as:

Wegovy is also FDA approved to reduce the risk of major cardiovascular (heart and blood vessel) events in adults. Recently, Wegovy received FDA accelerated approval to treat MASH without cirrhosis in adults who have moderate to advanced liver fibrosis. (MASH was formerly known as nonalcoholic steatohepatitis [NASH].) Final approval of the MASH indication may depend on further study.

Read on to learn what you might expect in your first week of treatment with Wegovy and beyond. You can also learn how long it generally takes to see noticeable weight loss.

Note: Combining Wegovy with diabetes or other weight loss medications can cause serious side effects. It’s important to use other drugs only if your doctor says it’s okay to do so. Also, do not change your dosage without first talking with your doctor.

Continue reading to learn what you might expect in your first week of treatment with Wegovy. Your results and side effects may depend on the condition Wegovy is treating. Other conditions you may have and other medications you take also could affect your results and side effects.

What first-week results can I expect with Wegovy?

You’re unlikely to see any noticeable changes in your weight during the first week of Wegovy treatment. It takes some time for the medication to take effect. Even so, your doctor may notice changes in some of your health markers. These might include blood pressure or blood sugar levels.

Most studies examining the effectiveness of Wegovy for weight loss have looked at results over 12 weeks or longer. But some people may have noticeable weight loss in 4 weeks or even less.

Scene viewed through an open door of two dark-skinned women with short, dark hair standing face-to-face in an office that has a small desk, some chairs, and a side table: the woman on the left in a lab coat is measuring the waist of the woman on the right (wearing street clothes) with a tape measureShare on Pinterest
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What first-week side effects can I expect with Wegovy?

In their first week of treatment, some people may develop side effects. These might occur within hours to days of their first dose. But the timing and degree of side effects vary widely among people.

Some of the most common side effects of Wegovy include:

Learn what you might expect with Wegovy once you’ve completed your first week of treatment.

What results can I expect in the first month and later?

It depends. Some people may find that Wegovy is effective for weight loss. Others might not lose much or any weight. Losing weight can take longer for some people, and it may be affected by the dosage of Wegovy and the length of treatment.

A 2021 study compared weight loss in people taking semaglutide and people taking a placebo. (Remember, semaglutide is the active ingredient in Wegovy. A placebo is a substance with no active drug or ingredient.) Researchers found that weight loss measured at the marker of 4 weeks was statistically significant in those taking semaglutide. They also found that weight loss reached its maximum at 60 weeks of treatment.

In other studies, researchers examined weight loss with semaglutide and specific dosages. They found that weight loss was generally greater with higher doses of semaglutide. In summary:

  • Weight loss at 12 weeks measured:
    • 4% among people using 1-milligram (mg) injections weekly
    • 5% among people using 2.4-mg injections weekly
  • Weight loss by 28 weeks measured:
    • 7% among people using 1-mg injections weekly
    • 9.6% among people using 2.4-mg injections weekly

What side effects can I expect in the first month and later?

It’s not uncommon to experience side effects after your first week of Wegovy treatment. But keep in mind that the timing and degree of side effects vary widely among people.

If you do develop side effects, it’s important to know that doesn’t mean you are more or less likely to experience weight loss. During Wegovy treatment, common side effects in the first month and later include:

In clinical studies, some people had side effects that persisted. About 8% of these people discontinued medications containing semaglutide. (Semaglutide is the active ingredient in Wegovy.)

Wegovy side effects generally lessen over time as your body adjusts to the medication. You may be able to reduce some side effects of Wegovy by adjusting your dose. But it’s important not to adjust your dose without first discussing it with your doctor.

Some people develop serious side effects. In these cases, your doctor may recommend reducing your dose or stopping the medication.

The following tips may help you manage some common side effects of Wegovy.

Nausea and vomiting

If you develop nausea or vomiting, it’s a good idea to talk with your doctor. Either side effect could be a sign of gallbladder problems or pancreatitis.

You might try the following home remedies to help reduce nausea:

  • drinking small sips of cold drinks
  • avoiding greasy or fatty foods
  • eating bland foods, such as crackers, rice, or applesauce
  • avoiding exercise after eating

To help avoid vomiting, consider smelling alcohol swabs.

Constipation

If you have constipation, you may be able to relieve it by:

  • drinking more fluids
  • exercising regularly
  • increasing your fiber intake

Your doctor may recommend over-the-counter (OTC) treatments for constipation if home remedies are not effective.

Diarrhea

When you have persistent diarrhea, stay hydrated to prevent dehydration. It’s also a good idea to avoid caffeine and alcohol (if you drink). Broths or sports drinks can help replenish your levels of electrolytes.

It’s believed that Wegovy decreases appetite due to direct and indirect effects on the brain. This causes you to eat less food (thus taking in fewer calories), which results in weight loss. This may help reduce some cardiovascular and other risks associated with obesity, overweight, and MASH.

Uses for weight loss and reduced cardiovascular events

During Wegovy treatment, you might notice some things in how you feel. You might experience differences in:

Your appetite: With Wegovy, people generally recognize when they’re full after a snack or a meal. Some also report staying full longer. Others note that they eat less.

Food cravings: Numerous people find that they have fewer cravings for certain foods. They find that they’re able to ignore cravings to snack or eat more easily.

Wanting to eat: Some people are familiar with the desire to eat when they’re not hungry. With Wegovy, they may experience that desire less.

Food choices: Compared with their before-treatment choices, many people report that they choose healthier foods to eat. They also note that they can account for why they made these choices.

Some day-to-day choices: With Wegovy, people sometimes find that they make different choices about activities. Some make choices that are not centered around food, such as going out but not necessarily going out to eat.

It’s possible that you could experience other health-related differences in how you feel. Some may be obvious and others not. Examples include:

  • reduction in overweight or obesity
  • improvement in cardiovascular risk markers
  • lowered blood pressure
  • lowered blood sugar
  • decreased lipid levels (Lipids are chemical elements in the body’s cells.)
  • changes in certain proteins that may reduce inflammation
  • improved overall functioning of the body

Some differences concerning weight loss and reduced cardiovascular events will depend on your specific condition. They also may depend on other medications you take and other conditions you may have.

Use for MASH

With Wegovy treatment for MASH, you could notice reduced liver inflammation, which was noted in the study. Reduced liver inflammation may lead to:

  • less fatigue
  • improvement in skin color
  • less nausea and vomiting
  • reduced pain, especially in the belly area
  • reduction in liver fibrosis (scarring)

Some differences concerning MASH will depend on your condition. They also may depend on other conditions you might have and other medications you take.

You can help increase or promote weight loss with Wegovy in several ways. This section discusses a few of those.

Choose nutritious foods to help reduce calories

For several of Wegovy’s prescribed uses, doctors also prescribe a diet with fewer calories. To intake fewer calories, you can choose foods that are dense in nutrients. These include:

  • fruits
  • vegetables
  • whole grains
  • healthy protein sources

Rightsize your portions

You can help intake fewer calories when you control portion sizes. Try to form the habit of checking serving sizes on nutrition labels to guide your portion sizes. Rather than using a dinner plate, you can select a smaller dish and fill it with one serving.

Eat slowly

Eat at a slower pace. Enjoy the textures, aromas, and flavors of your food.

Keep water handy

Water can help you feel full. Plus, it can keep you energized and hydrated. Keep a water bottle nearby and even in several places so you’ll always have one handy.

Increase your physical activity

Along with prescribing fewer calories, doctors also may prescribe increased physical activity with Wegovy. Some suggestions are:

  • Find what’s fun in fitness: Discover ways to stay active that you can enjoy. Explore by walking, dancing, jogging, weightlifting, playing tennis, or doing other activities that keep you moving.
  • Go with a buddy: Plan physical activities with family and friends. While you spend time together, you can work toward your weight-management goals.
  • Bundle the activity with what interests you: Do your workout or activity with something that makes you want to do it. You could try working out or other physical activity while you:
    • listen to music you love
    • catch up on your favorite TV program
    • listen to a podcast
    • explore your favorite park
  • Change up activities: Try changing activities here and there to keep your interest high. You could try walking vigorously one day and then running lightly the next. Or use weights while you walk or dance instead of just weightlifting.
Medical Perspective

How does exercise affect blood sugar levels and insulin sensitivity?

Exercise increases uptake of glucose by your muscles and liver so that your body can use it for energy. Your body then takes glucose from your blood to rebuild these stores, thereby lowering blood sugar. Exercise also makes your body more sensitive to insulin, so you will need less insulin during and after activity.

— Kelly Wood, MD

Learn more about exercising safely if you take insulin.

Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Wegovy is an FDA-approved medication for weight loss in certain people who are overweight or have obesity. It is also FDA approved for other uses, including MASH.

You’re not likely to notice weight loss within your first week of treatment. But your doctor may notice changes in some of your health markers, such as your blood pressure or blood sugar. Over time, you could notice other differences in your appetite, how you feel, and more.

You may develop side effects during the first week of treatment or later. The most common side effects of Wegovy affect your gastrointestinal tract. These include:

  • nausea
  • vomiting
  • constipation
  • diarrhea

Side effects may ease as your body becomes used to the medication.

Your doctor may be able to lessen some side effects of Wegovy by adjusting your dose. Be sure to discuss adjusting your dose with your doctor rather than adjusting it on your own. Your doctor also might recommend OTC treatments for some side effects if you find that home remedies aren’t effective.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.