Your first week on Wegovy is unlikely to produce noticeable weight loss or dramatic changes. The starting dose, 0.25 mg injected once weekly, is intentionally low to let your body adjust to the medication before the dose increases over several months. What you can expect is a relatively gentle introduction, possibly some digestive side effects, and the practical learning curve of giving yourself a weekly injection.
The Starting Dose Is Intentionally Small
Wegovy’s FDA-approved starting dose is 0.25 mg, administered as a once-weekly injection under the skin. You’ll stay at this dose for the first four weeks before moving up. The maintenance dose that most people eventually reach is ten times higher, so this first month is really about easing your body into the medication rather than producing significant results.
At this low dose, the drug is already beginning to work on a biological level. Semaglutide, Wegovy’s active ingredient, mimics a gut hormone called GLP-1 that your body naturally releases after eating. It slows how quickly food leaves your stomach, helps regulate blood sugar, and acts on appetite-related pathways in the brain. Research shows that the effect on gastric emptying is actually most pronounced early in treatment (within the first four weeks), even though weight loss hasn’t kicked in yet. That delay in stomach emptying is part of why you may feel full faster or slightly “off” with food, even before the scale moves.
Don’t Expect Weight Loss Yet
This is probably the most important expectation to set: you are not likely to notice any weight change during week one. The 0.25 mg dose is a titration dose, not a therapeutic one. It exists solely to minimize side effects as your body adjusts. Meaningful weight loss with Wegovy typically begins after several dose increases, and clinical trials measured results over months, not days. If you step on the scale after your first injection and nothing has changed, that’s completely normal and expected.
Appetite Changes Vary Widely
Some people report a subtle reduction in hunger or “food noise” within the first few days of their injection. Others feel no difference at all during the first week. Both responses are normal at this dose. The appetite-suppressing effects become more noticeable as the dose increases over the following months. If you’re eating the same amounts you were before starting, don’t worry that the medication isn’t working. It simply hasn’t had enough time or dose strength to produce that effect for most people.
If you do notice a poor appetite or find it hard to eat, focus on nutrient-dense options that are easy to get down. High-protein smoothies and blended soups made with vegetables and beans can help you meet basic nutritional needs without requiring you to sit through a full meal.
Common Side Effects in the First Week
The most frequently reported side effects of Wegovy are gastrointestinal: nausea, diarrhea, vomiting, and constipation. At the 0.25 mg starting dose, these tend to be mild when they occur at all. Nausea is the most common complaint. It often shows up a day or two after the injection and may last a few days before fading.
A few practical strategies can help. Eating smaller, more frequent meals rather than large ones reduces the burden on a stomach that’s emptying more slowly than usual. Bland, low-fat foods tend to sit better than rich or greasy ones. Staying well-hydrated matters, especially if you experience any vomiting or diarrhea, since dehydration is one of the more serious risks of persistent GI symptoms.
Not everyone gets side effects. Some people breeze through the first week feeling completely normal. The low starting dose is specifically designed to make this phase as tolerable as possible.
Giving Yourself the Injection
Wegovy comes in a prefilled, single-use pen with a hidden needle, so you won’t see the needle before or during the injection. You inject it once a week, on the same day each week, into one of three recommended sites: your lower stomach (at least two inches from the belly button), the front of your thighs, or your outer upper arm. The upper arm is easier if someone else gives you the injection.
Rotate your injection site each week. Using the same spot repeatedly can cause skin irritation, lumps, or scarring over time. You can alternate between your stomach and thigh, for example, or move to different areas within the same general region. The injection itself takes only a few seconds and most people describe it as a brief pinch or pressure rather than real pain.
Storing Your Pen Correctly
Keep your Wegovy pens in their original carton in the refrigerator, between 36°F and 46°F. If you need to take a pen out of the fridge (for travel, for instance), it can stay at room temperature for up to 28 days as long as the temperature stays below 86°F and you haven’t removed the pen cap. After 28 days out of the fridge, or if the pen has been exposed to temperatures above 86°F, throw it away. Never freeze Wegovy, and don’t use a pen if the liquid looks cloudy or contains particles.
Serious Symptoms to Watch For
Serious side effects at the starting dose are rare, but it’s worth knowing the warning signs. Severe, persistent nausea or vomiting that prevents you from keeping fluids down can lead to dehydration and kidney problems. Sudden, intense abdominal pain that radiates to your back could signal pancreatitis. Rapid heart rate, signs of an allergic reaction (swelling of the face, lips, or throat, difficulty breathing), or yellowing skin could indicate other serious issues.
Wegovy also carries a boxed warning about thyroid tumors, based on animal studies. While this risk hasn’t been confirmed in humans, the medication is not prescribed for people with a personal or family history of a type of thyroid cancer called medullary thyroid carcinoma. If you notice a lump or swelling in your neck, hoarseness, or difficulty swallowing, that warrants prompt medical attention.
What Week One Actually Looks Like
For most people, the first week of Wegovy is uneventful. You give yourself the injection, possibly feel a bit queasy for a day or two, and otherwise go about your normal routine. You won’t see weight loss. You may or may not notice a subtle shift in how hungry you feel. The real changes come gradually over the following weeks and months as your dose increases. Think of this first week as your body’s introduction to the medication, not the beginning of visible results.