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Key takeaways
Wegovy is an FDA-approved injectable medication for chronic weight management. It contains the same active ingredient as Ozempic, semaglutide.
Most people are able to easily self-administer Wegovy for the first time, following simple instructions from their healthcare provider and, if needed, utilizing online tutorials.
Expect to feel normal on your first day taking Wegovy since the side effects don’t start immediately.
The most common side effects of Wegovy start a few days after the injection and include nausea, gastrointestinal discomfort, and decreased appetite. More serious side effects are rare but include allergic reactions and pancreatitis, both of which require immediate medical attention.
If you’ve considered taking Ozempic for weight management but discovered it’s only approved by the Food and Drug Administration (FDA) for the treatment of Type 2 diabetes, there is another possible option: Wegovy. It’s similar to Ozempic both in how it’s administered (by injection) and its active ingredient (semaglutide). But, unlike Ozempic, Wegovy is FDA approved for chronic weight management in certain populations, including people 12 years and older who meet specific body mass index (BMI) requirements or have other health conditions affecting their cardiovascular health.
The recent popularity of injectable weight loss drugs has given many people a sense of familiarity with them, but it can still feel intimidating when you’re sent home with your first dose of Wegovy. While your healthcare provider or pharmacist will likely have talked to you about how to self-administer Wegovy, you may have more questions about what you can expect after taking your first dose. Here’s everything you need to know to get started with your first dose of Wegovy, from where to inject it and what it will feel like to when you can expect results (and potential side effects).
How to use the Wegovy pen
Wegovy comes in a single-use pen that is pre-loaded with your dose. According to Jared Braunstein, DO, an internist with Medical Offices of Manhattan and contributor to LabFinder, the usual starting dose of Wegovy is 0.25 milligrams (mg) once a week. Starting at a higher dose isn’t advised, because your body needs time to adjust to the medication.
It’s important to follow the instructions your healthcare provider or pharmacist has given you about injecting yourself with the Wegovy pen. Your prescription should also come with detailed instructions for use, and Wegovy’s manufacturer, Novo Nordisk, has this information (and a helpful instructional video) on its website for further reference. Wegovy should be kept refrigerated until use or kept at room temperature in its carton for a maximum of 28 days. “You can take it with or without food,” says Dr. Braunstein. Be mindful of the medication’s environment. Do not let the medication freeze or stay in a hot car or mailbox.
Per Novo Nordisk, the basic steps for using the Wegovy pen are as follows:
- Wash your hands.
- Inspect your pen for defects, including cracks on the outside of the pen or discolored medication inside the pen. Check that the expiration date has not passed.
- Choose an injection site (if you need more help, read more about where and how to inject Wegovy), and clean the injection site with rubbing alcohol or soap and water. Pat the area dry.
- Remove the medication’s pen cap.
- Place the pen against the injection site and press down to get the yellow injection bar moving. You will hear two clicks during this process. Once the yellow bar has stopped moving, the injection is complete, and you can slowly lift the pen away from your skin.
- Dispose of the pen in an FDA-approved sharps container (or acceptable alternative) and gently dab any blood at the injection site with a cotton pad or ball.
What to expect the first time taking Wegovy
The first time you take Wegovy, you shouldn’t expect anything noticeable to happen. That may change quickly, however, as side effects usually kick in within the first few days after a dose. Here’s what to expect.
What are the first-day side effects of Wegovy?
The majority of Wegovy side effects don’t start on the first day. Dr. Braunstein says most people don’t feel anything right away, which means you don’t need to plan your life around your first Wegovy dose: You can drive, go to work, eat normally, and otherwise go about your normal routine. Over time, Wegovy may cause some fatigue, but don’t expect it to happen suddenly.
“The only side effect you might experience on the first day is injection-site irritation, such as redness, swelling, and itching,” says Alexandria Lightning, DNP, founder of Lightning VIP. Irritation at the injection site typically decreases with continued use.
Common Wegovy side effects: First weeks and beyond
While you will probably feel totally normal on your first day taking Wegovy, Dr. Lightning says that side effects usually begin within the first few days after a dose and may include:
- Nausea and vomiting, especially when starting or increasing the medication
- Gastrointestinal issues like diarrhea and constipation
- Abdominal pain
- Indigestion
- Fatigue
- Headache
- Decreased appetite
Wegovy works as a weight loss treatment because it suppresses your appetite, Dr. Lightning notes, so a noticeable decrease in hunger is counted among the early symptoms of taking the drug. As you move beyond the first few weeks, that decreased appetite should start leading to sustained weight loss. In fact, in a double-blind clinical trial of people who took semaglutide over 68 weeks, 69% of participants lost at least 10% of their body weight within 68 weeks of taking Wegovy, and 50.5% lost at least 15%.
“There may also be other health benefits observed with long-term use of Wegovy,” Dr. Lightning says, “including better blood sugar control and a lower risk of cardiovascular events.”
RELATED: How long does Wegovy stay in your system?
Serious Wegovy side effects
More serious side effects of Wegovy are rare but possible, so it’s important to know what to look for throughout the course of treatment. If you experience any serious side effects, contact your healthcare provider right away or go to the nearest emergency care center, as some of these could be signs of a life-threatening medical condition.
According to Dr. Lightning, these are the serious side effects to be especially aware of when taking Wegovy:
- Inflammation of the pancreas, or pancreatitis, which may appear at first as a fever and severe abdominal pain below the breastbone (that can radiate to the back)
- Gallstones, especially if you’ve had significant weight loss while taking it. Gallstones may feel like right-upper-quadrant abdominal pain that worsens after a fatty meal.
- Dehydration and other kidney issues as a result of gastrointestinal side effects like vomiting
- Hypoglycemia, or low blood sugar, which is more common in people with Type 2 diabetes taking other medications that lower blood sugar
- Severe allergic reaction, which may appear as difficulty breathing or swelling of the face, lips, tongue, or throat
Again, these side effects are not common, but they are potentially dangerous. Don’t hesitate to seek medical attention if you’re experiencing any of them.
RELATED: Wegovy results: First month and beyond │ How quickly does Wegovy work?
Sources
- Wegovy pen instructions, Novo Nordisk
- Once-weekly semaglutide in adults with overweight or obesity, New England Journal of Medicine (2021)
- FDA approves first treatment to reduce risk of serious heart problems specifically in adults with obesity or overweight, Food & Drug Administration (2024)
