Wegovy Side Effects: What to Expect, How Long They Last and How to Track Them
The most common Wegovy side effects are nausea, diarrhea, vomiting and constipation, and for most people they're mild to moderate and fade as the body adjusts to each dose. In weight-loss trials of Wegovy 2.4 mg, 44% of adults had nausea, mostly while the dose was being increased, and more than 9 in 10 stayed on treatment (Wegovy prescribing information). Knowing what's normal makes the first months much easier. Glapp, a Wegovy dose tracker, lets you log every side effect right next to your Wegovy doses, so you can see what each step does and watch it settle.
Key numbers
| Number | What it means |
|---|---|
| 44% | of adults on Wegovy 2.4 mg had nausea in weight-loss trials, the most common side effect, vs 16% on placebo |
| 17,436 | users currently tracking Wegovy side effects in Glapp |
| 6.8% | stopped Wegovy because of side effects, vs 3.2% on placebo |
Wegovy side effects: what the clinical trials show
Wegovy's prescribing information pools placebo-controlled weight-loss trials of semaglutide 2.4 mg in adults (1,261 people on placebo, 2,116 on Wegovy). These are the side effects reported by at least 2% of people and more often than on placebo:
| Side effect | Placebo | Wegovy 2.4 mg |
|---|---|---|
| Nausea | 16% | 44% |
| Diarrhea | 16% | 30% |
| Vomiting | 6% | 24% |
| Constipation | 11% | 24% |
| Abdominal pain | 10% | 20% |
| Headache | 10% | 14% |
| Fatigue | 5% | 11% |
| Indigestion (dyspepsia) | 3% | 9% |
| Dizziness | 4% | 8% |
| Bloating (abdominal distension) | 5% | 7% |
| Burping (eructation) | <1% | 7% |
| Gas (flatulence) | 4% | 6% |
| Stomach bug (gastroenteritis) | 4% | 6% |
| Acid reflux (GERD) | 3% | 5% |
| Stomach lining irritation (gastritis) | 1% | 4% |
| Viral gastroenteritis | 3% | 4% |
| Hair loss | 1% | 3% |
| Altered skin sensation (dysesthesia) | 1% | 2% |
Source: Wegovy prescribing information, Table 3.
Overall, 73% of people on Wegovy had at least one stomach side effect, compared with 47% on placebo, most often while the dose was being increased. Severe stomach side effects were uncommon: 4.1% vs 0.9%. In STEP 1, the main weight-loss trial (1,961 adults, 68 weeks), people on semaglutide 2.4 mg lost 14.9% of their body weight vs 2.4% on placebo, and stomach side effects were mostly mild to moderate and temporary.
Common Wegovy side effects, one by one
Each of these has its own guide with the full data, the causes and a tracking plan.
- Nausea (44%). The most common side effect, usually strongest in the days after a shot and after each dose step. Full guide
- Diarrhea (30%). Mostly during dose escalation; fluids and electrolytes matter most. Full guide
- Vomiting (24%). Usually travels with nausea, so the nausea guide covers it. Full guide
- Constipation (24%). Slower digestion plus eating less; fiber, fluids and movement help. Full guide
- Heartburn, indigestion and burping (5–9%). Food stays in the stomach longer. Full guide
- Stomach pain, bloating and gas (6–20%). Usually mild and tied to the same slower digestion. Severe or lasting pain is different: call your prescriber.
- Headache (14%). On Wegovy's list, unlike tirzepatide's, and often linked to dehydration and skipped meals. Full guide
- Fatigue (11%). Often linked to eating and drinking much less in the first months. Full guide
- Dizziness and low blood pressure (8%; 1.3% vs 0.4%). More likely when you're dehydrated or your blood pressure falls as you lose weight.
- Hair loss (3%). Temporary shedding (telogen effluvium) that follows fast weight loss, usually a few months in.
- Altered skin sensation (2%). Tingling, sensitivity or a burning feeling on the skin, reported by a small number of people.
Why does Wegovy cause side effects?
Wegovy (semaglutide) is a GLP-1 receptor agonist. It mimics GLP-1, a gut hormone (an incretin) that tells your brain you're full and slows how quickly your stomach empties (gastric emptying). Those same actions drive weight loss and explain most side effects:
- Slower gastric emptying. Food stays in the stomach longer, which brings fullness, nausea, burping, heartburn and, further down, constipation.
- Changes in gut movement. The gut needs time to adjust, which is why diarrhea, bloating and gas cluster in the first weeks of each dose.
- Eating much less. Lower appetite and quieter food noise mean fewer calories, less fluid and often less protein, which can bring tiredness, headaches, dizziness and, a few months in, hair shedding.
- A long escalation. Wegovy steps up four times over 16 weeks, so there are five adjustment periods before you reach 2.4 mg. Side effects often come in waves through the first four months.
How long do Wegovy side effects last?
For most people, Wegovy side effects are a phase, not a permanent state. They're strongest in the first one to two weeks after you start and after each dose increase, then ease as your body adjusts. Within each week, many people feel them most a day or two after the shot: semaglutide reaches its highest level 1–3 days after an injection. Wegovy reaches a steady level after about four to five weeks at the same dose, so once you've settled on your maintenance dose, side effects usually calm down for good.
| Side effect | How long it usually lasts | When to call your prescriber |
|---|---|---|
| Nausea | A few days after each shot; eases over weeks at a stable dose | You can't keep food or fluids down |
| Diarrhea | A few days per episode, mostly during dose escalation | It lasts more than a couple of days, or comes with blood, fever or dizziness |
| Constipation | Can linger longer than other stomach side effects | No bowel movement for more than three days, or severe pain |
| Headache | Hours to a day, usually on low-fluid or low-food days | It's sudden and severe, or comes with vision changes or confusion |
| Fatigue | The first weeks and after each dose step | It doesn't lift after a few weeks on the same dose |
| Hair loss | Starts two to four months in; regrowth within six to twelve months | Shedding lasts more than six months or comes in patches |
Wegovy's half-life is about one week, so after a last dose it takes around five weeks to leave your body, and side effects fade over that time.
Track your Wegovy side effects with a GLP-1 tracking app and stay in control: your 30-day plan
With four dose steps in the first 16 weeks, side effects on Wegovy can come and go in waves. A Wegovy progress tracker turns those waves into a pattern you can see: log how you feel each day next to your Wegovy doses, and you're in control. You'll know which day after your shot each side effect peaks, which step brought it on and whether it's easing, and you'll walk into your next appointment with facts instead of guesses.
Why Glapp? It's a top-rated GLP-1 tracking app used by 100,000+ people, rated 4.8/5 on Trustpilot and the App Store, and 4.6/5 on Google Play. Glapp grew out of Reddit GLP-1 support groups and is built by people who take GLP-1 medications themselves, so most of what's in it came straight from what the community asked for: daily side-effect check-ins, an estimated Wegovy level, custom titration curves for your dose steps and a doctor's report you can share. It's grounded in published clinical trial data and peer-reviewed research, core tracking is free, and it syncs across iPhone, Android and web. Here's how to use it over your first 30 days.
Glapp does not provide medical advice or treat side effects. It shows your daily check-ins against your estimated medication levels so you have structured data to share with your prescriber.
Day 1: Start tracking your side effects
Use Glapp's daily check-in to record any side effect you notice, from nausea to headaches, and rate how severe it feels. Log your Wegovy dose and injection time too, so everything that follows is based on what you actually took.
Daily entries help you see whether each side effect is getting better, getting worse or staying the same. You'll have a clear record of how you felt, without having to remember every day.
Day 3: Compare symptoms with your estimated Wegovy level
Glapp estimates your medication level throughout the day using your dose and injection time. Wegovy typically reaches its highest blood concentration 1–3 days after an injection.
Seeing your symptoms alongside this estimate helps you spot when each side effect appears within your shot cycle. As you log more days, you can look for a repeating pattern and know when to pay closer attention.
The medication level is an estimate, not a blood test, and a matching pattern does not prove what caused your symptoms.
Day 7: See how your side effects change over time
Open the side-effects chart in the Progress tab and choose the period you want to review. Your daily ratings appear on a timeline, making it easier to see whether a difficult day was an isolated episode or part of a longer trend.
Day 14: Look for patterns in your weekly report
Glapp's weekly progress report brings your logged data together, with dedicated sections showing your side effects and how they change.
Do side effects return on the same day after your shot? Did they start after a dose step? Do they coincide with changes in hunger or food noise? Reviewing two weeks of entries can help you spot patterns that are easy to miss day by day, and give you specific questions to discuss with your doctor.
Day 30: Bring a clear record to your doctor
After a month, review the bigger picture: are your side effects becoming less frequent, staying the same or getting worse? Wegovy generally reaches a steady repeating level after about four to five weeks of weekly injections at the same dose, so a month of entries shows you how your body handled that step.
Create a doctor's report in Glapp and choose the information to include. Your doctor can review your symptom history alongside your doses and progress, giving you a more focused conversation about your treatment and your next dose step.
Start tracking your Wegovy side effects in Glapp
Wegovy side effects by dose: what changes at each step
Wegovy goes up every four weeks until you reach a maintenance dose, usually 2.4 mg (1.7 mg is also an option):
| Weeks | Weekly dose | What to expect |
|---|---|---|
| 1–4 | 0.25 mg | Starter dose; mild side effects are common as your body meets the medication |
| 5–8 | 0.5 mg | First step up; a new week or two of adjustment |
| 9–12 | 1 mg | Appetite drops further; watch fluids and protein |
| 13–16 | 1.7 mg | Often the step where side effects return most clearly |
| 17 onward | 2.4 mg | Maintenance; side effects usually settle within weeks |
The trial rates on this page are at 2.4 mg and aren't broken down by step, so your own log is the best guide to what each step does for you. If side effects get hard to manage after a step, prescribers can keep you on a dose for longer before the next one.
What to bring to your prescriber
Glapp's doctor's report puts your side effects, doses and progress on one page. Before your appointment, check it shows:
- which side effects you had and how severe they were
- which day after your shot they peaked
- whether they started after a dose step
- any day you couldn't eat or keep fluids down
Questions you could ask. They're conversation starters, not recommendations; your prescriber decides what, if anything, to change.
- "My nausea came back after the 1.7 mg step. Is that expected on Wegovy?"
- "Could I stay on this dose longer before stepping up?"
- "Which side effects should make me call you straight away?"
Frequently asked questions
How long do Wegovy side effects last?
For most people, a few weeks per dose step. Side effects are usually strongest in the first one to two weeks after starting and after each increase, peak a day or two after each shot, and settle once you've been on your maintenance dose for about a month. Hair shedding is the exception: it starts later and takes months to grow back.
What are the most common side effects of Wegovy?
Nausea (44%), diarrhea (30%), vomiting (24%) and constipation (24%) were the most common in weight-loss trials, followed by abdominal pain, headache and fatigue.
When do Wegovy side effects start?
Often within the first few days after your first shot or a dose increase, as semaglutide reaches its peak level 1–3 days after injection.
Do Wegovy side effects go away?
Yes, for most people. Stomach side effects were most common during dose escalation and were mostly mild to moderate and temporary in STEP 1, and more than 9 in 10 people in the trials stayed on treatment.
Are Wegovy and Ozempic side effects the same?
Both contain semaglutide, so the same side effects are expected. Wegovy is the version approved for weight loss and goes up to 2.4 mg, while Ozempic's highest dose is 2 mg. See Ozempic side effects.
How do I track Wegovy side effects?
Log them in Glapp's daily check-in and rate each one low, medium or high, next to your Wegovy dose. Glapp shows each rating against your estimated medication level, and your weekly reports show which day after the shot each side effect peaks.
About the data
Ratings are self-reported and medication levels are estimated from dose and timing, not measured. This page is for information only and is not medical advice; talk to your prescriber about any side effect.
About the author
We're GLP-1 patients and health tech professionals, building Glapp in collaboration with doctors. About us
Sources
- Novo Nordisk. Wegovy (semaglutide) injection prescribing information: Table 3, warnings and precautions, dosage, pharmacokinetics.
- Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384:989–1002.