Semaglutide (Ozempic and Wegovy) is incredibly effective for weight loss—but like all medications, it comes with potential side effects. The good news? Most side effects are mild, temporary, and manageable with the right strategies.

Understanding what to expect, which side effects are normal, and how to minimize discomfort can make your semaglutide journey much smoother. This complete guide covers all semaglutide side effects, from common and temporary to rare and serious, plus proven strategies to manage them.

Most Common Semaglutide Side Effects

These side effects occur in 10-40% of people taking semaglutide, especially during the first few weeks or after dose increases.

1. Nausea (Most Common)

How common: 20-44% of people experience nausea

When it occurs:

• Most common in first 1-2 weeks on medication
• Often returns after dose increases
• Usually improves or resolves after 4-8 weeks
• Worse on empty stomach or after eating large/fatty meals

How to manage nausea:

• Eat smaller, more frequent meals (5-6 small meals vs. 3 large)
• Avoid trigger foods: Greasy, fried, spicy, or very sweet foods
• Eat bland foods: Crackers, toast, rice, bananas, chicken
• Stay upright after eating: Don't lie down for 2-3 hours
• Ginger: Ginger tea, ginger chews, or ginger supplements
• Cold foods: Often better tolerated than hot foods
• Timing: Take injection in evening (sleep through worst nausea)
• Slow eating: Chew thoroughly, eat slowly
• Hydration: Sip water throughout the day (not large amounts at once)

When to contact provider: If nausea is severe, persistent, or accompanied by vomiting that prevents eating/drinking

2. Vomiting

How common: 9-24% of people

When it occurs:

• Usually accompanies severe nausea
• More common after eating too much or too quickly
• Can occur after dose increases

How to manage:

• Follow all nausea management strategies above
• Eat even smaller portions
• Stop eating at first sign of fullness
• Avoid overeating (medication slows gastric emptying)
• Stay hydrated with small sips of water or electrolyte drinks
• Consider anti-nausea medication (ask your provider about ondansetron/Zofran)

When to contact provider: If vomiting persists for 24+ hours or you can't keep down fluids

3. Diarrhea

How common: 8-30% of people

When it occurs:

• Can occur anytime, especially early in treatment
• May be triggered by fatty or greasy foods
• Usually temporary (improves within weeks)

How to manage:

• Avoid trigger foods: Greasy, fried, high-fat foods
• BRAT diet: Bananas, rice, applesauce, toast
• Stay hydrated: Drink plenty of water and electrolytes
• Probiotics: May help normalize gut bacteria
• Limit dairy: If lactose intolerant
• Avoid artificial sweeteners: Can worsen diarrhea
• Soluble fiber: Psyllium husk can help (start low dose)

When to contact provider: If diarrhea is severe, bloody, or lasts more than a few days

4. Constipation

How common: 10-24% of people

Why it happens: Semaglutide slows gastric emptying and gut motility

How to manage:

• Hydration: 8-10 glasses of water daily (most important!)
• Fiber: 25-35g daily from vegetables, fruits, whole grains
• Prune juice: 4-8 oz in the morning
• Magnesium citrate: 300-400 mg before bed
• Movement: Daily walking stimulates gut motility
• Probiotics: Support digestive health
• Kefir: 1-2 cups daily for probiotics
• Avoid: Processed foods, excessive cheese/dairy

When to contact provider: If no bowel movement for 5+ days or severe abdominal pain

5. Abdominal Pain or Discomfort

How common: 5-20% of people

Types:

• Bloating and gas
• Cramping
• General stomach discomfort
• Feeling of fullness

How to manage:

• Eat smaller portions
• Avoid gas-producing foods (beans, cruciferous vegetables, carbonated drinks)
• Eat slowly and chew thoroughly
• Gentle abdominal massage
• Warm compress on abdomen
• Peppermint tea (helps with gas and bloating)
• Walk after meals (aids digestion)

When to contact provider: If pain is severe, persistent, or located in upper right abdomen (could indicate gallbladder issues)

6. Fatigue

How common: 5-15% of people

When it occurs:

• Most common in first 2-4 weeks
• Can occur with dose increases
• May be related to reduced calorie intake

How to manage:

• Adequate calories: Don't eat too little (minimum 1,200-1,500 calories)
• Protein: Ensure adequate protein intake (0.8-1g per pound goal weight)
• Hydration: Dehydration causes fatigue
• Sleep: Prioritize 7-9 hours nightly
• B vitamins: B-complex supplement may help
• Iron: Check iron levels if fatigue persists
• Gentle exercise: Light activity can boost energy

When to contact provider: If fatigue is severe or doesn't improve after first month

7. Headache

How common: 5-14% of people

How to manage:

• Stay well-hydrated
• Maintain regular meal times (don't skip meals)
• Adequate sleep
• Manage stress
• Over-the-counter pain relievers (acetaminophen, ibuprofen) as needed
• Caffeine in moderation (can help or worsen headaches)

8. Injection Site Reactions

How common: 5-10% of people

Symptoms:

• Redness
• Swelling
• Itching
• Bruising
• Mild pain or tenderness

How to manage:

• Rotate injection sites: Abdomen, thigh, upper arm
• Clean skin: Use alcohol wipe before injection
• Room temperature: Let pen warm to room temp before injecting
• Proper technique: Insert needle quickly at 90-degree angle
• Don't reuse needles: Use new needle each time
• Ice before/after: Can reduce discomfort
• Avoid same spot: Wait at least 1 week before using same area

Less Common Side Effects (1-10% of People)

Acid Reflux/Heartburn

Management:

• Avoid trigger foods (spicy, acidic, fatty)
• Don't lie down for 3 hours after eating
• Elevate head of bed
• Smaller meals
• Antacids as needed (Tums, Pepcid)

Dizziness

Management:

• Stay hydrated
• Stand up slowly (avoid sudden position changes)
• Eat regular meals (avoid low blood sugar)
• Check blood pressure if persistent

Burping/Belching

Management:

• Eat slowly, chew thoroughly
• Avoid carbonated beverages
• Don't drink through straws
• Avoid chewing gum

Loss of Appetite (Extreme)

Management:

• Eat small amounts frequently (even if not hungry)
• Focus on nutrient-dense foods
• Protein shakes if solid food is difficult
• Track calories to ensure adequate intake
• Discuss dose reduction with provider if needed

Rare but Serious Side Effects

These side effects are rare but require immediate medical attention:

Pancreatitis (Inflammation of Pancreas)

How rare: <1% of people

Symptoms:

• Severe upper abdominal pain (may radiate to back)
• Nausea and vomiting
• Fever
• Rapid pulse
• Tenderness when touching abdomen

Risk factors:

• History of pancreatitis
• Gallstones
• High triglycerides
• Heavy alcohol use

Action: Stop medication and seek immediate medical care if you experience these symptoms

Gallbladder Problems

How rare: 1-3% of people (more common with rapid weight loss)

Symptoms:

• Pain in upper right abdomen
• Pain between shoulder blades
• Nausea after eating fatty foods
• Yellowing of skin or eyes (jaundice)

Why it happens: Rapid weight loss increases gallstone risk

Action: Contact provider if you experience these symptoms

Kidney Problems

How rare: <1% of people

Symptoms:

• Decreased urination
• Swelling in legs, ankles, or feet
• Fatigue and weakness
• Confusion

Risk factors:

• Pre-existing kidney disease
• Severe dehydration from vomiting/diarrhea

Action: Contact provider immediately

Severe Allergic Reaction

How rare: Very rare (<0.1%)

Symptoms:

• Difficulty breathing
• Swelling of face, lips, tongue, or throat
• Severe rash or hives
• Rapid heartbeat
• Dizziness or fainting

Action: Call 911 or seek emergency medical care immediately

Hypoglycemia (Low Blood Sugar)

Risk: Low in people without diabetes; higher if taking insulin or sulfonylureas

Symptoms:

• Shakiness, trembling
• Sweating
• Rapid heartbeat
• Dizziness, confusion
• Extreme hunger
• Irritability

Action: Eat/drink 15g fast-acting carbs (juice, glucose tablets), recheck in 15 minutes

Thyroid Tumors (Animal Studies Only)

Important context: Thyroid tumors occurred in rodent studies but have NOT been confirmed in humans

Contraindication: Don't use semaglutide if you have:

• Personal or family history of medullary thyroid carcinoma (MTC)
• Multiple endocrine neoplasia syndrome type 2 (MEN 2)

Symptoms to watch for:

• Lump or swelling in neck
• Hoarseness
• Difficulty swallowing
• Shortness of breath

Timeline: When Side Effects Occur and Resolve

Week 1-2: Peak Side Effects

• Nausea is most common and severe
• Fatigue may occur
• GI symptoms (diarrhea, constipation, bloating)
• Headaches possible

Week 3-4: Improvement Begins

• Nausea typically starts to improve
• Body adjusts to medication
• Energy levels normalize
• GI symptoms may persist but improve

Week 5-8: Most Side Effects Resolve

• Nausea minimal or gone for most people
• GI symptoms much improved
• Feeling more normal overall
• Appetite suppression continues (this is desired effect)

After Dose Increases:

• Side effects may temporarily return (usually milder)
• Resolve more quickly than initial dose
• Follow same management strategies

Who Is Most Likely to Experience Side Effects?

Higher Risk:

• Starting at higher doses (should start at 0.25 mg)
• Increasing dose too quickly
• History of GI issues (IBS, GERD, gastroparesis)
• Eating large or fatty meals
• Not following dietary recommendations

Lower Risk:

• Starting at lowest dose (0.25 mg)
• Gradual dose escalation (4 weeks between increases)
• Following dietary guidelines
• Staying well-hydrated
• Eating smaller, frequent meals

How to Minimize Side Effects: Prevention Strategies

1. Start Low, Go Slow

• Always start at 0.25 mg weekly
• Wait full 4 weeks before increasing dose
• Don't rush to therapeutic dose
• If side effects are severe, stay at current dose longer

2. Dietary Modifications

• Eat smaller, frequent meals (5-6 small vs. 3 large)
• Avoid trigger foods: Greasy, fried, spicy, very sweet
• Protein first: Prioritize protein at every meal
• Eat slowly: Chew thoroughly, put fork down between bites
• Stop when satisfied: Don't eat until uncomfortably full

3. Hydration

• Drink 8-10 glasses of water daily
• Sip throughout the day (not large amounts at once)
• Add electrolytes if needed
• Avoid excessive caffeine and alcohol (dehydrating)

4. Timing of Injection

• Inject in evening so you sleep through worst nausea
• Same day each week for consistency
• Rotate injection sites

5. Supplements That May Help

• Ginger: Natural anti-nausea (tea, chews, capsules)
• Probiotics: Support gut health
• Magnesium citrate: Helps with constipation
• B-complex: May help with energy
• Fiber supplement: Helps regulate digestion (start low dose)

When to Contact Your Provider

Contact your provider if you experience:

• Severe, persistent nausea or vomiting (can't keep down food/fluids for 24+ hours)
• Severe abdominal pain (especially upper abdomen or right side)
• Signs of pancreatitis (severe upper abdominal pain radiating to back)
• Signs of gallbladder problems (pain in upper right abdomen)
• Severe allergic reaction (difficulty breathing, swelling, severe rash)
• Signs of kidney problems (decreased urination, swelling)
• Persistent diarrhea or constipation (5+ days)
• Severe fatigue that doesn't improve
• Any concerning symptoms that worry you

Your provider can:

• Prescribe anti-nausea medication (ondansetron/Zofran)
• Adjust your dose or dosing schedule
• Rule out serious complications
• Provide additional management strategies
• Determine if you should continue medication

Real Patient Experiences with Side Effects

Sarah, 48:

"The first two weeks were rough—I had nausea every day. But I followed all the tips: small meals, bland foods, ginger tea, and injecting at night. By week 3, the nausea was 80% better. By week 6, it was completely gone. Now I have no side effects and I've lost 35 pounds. Totally worth pushing through."

Michael, 55:

"I had terrible constipation in the first month. I started drinking prune juice every morning, taking magnesium at night, and drinking way more water. Problem solved. I also had some nausea, but eating smaller meals helped a lot."

Jennifer, 42:

"I was lucky—I only had mild nausea for about a week. I think starting at the lowest dose and increasing slowly made a big difference. I also avoided greasy foods and ate small portions. The side effects were minimal compared to the amazing weight loss results."

The Bottom Line

Semaglutide side effects are common but usually mild and temporary. Most people experience nausea, GI issues, or fatigue in the first few weeks, but these symptoms typically resolve by week 4-8.

Key takeaways:

• Most side effects are temporary (improve within 4-8 weeks)
• Nausea is most common (20-44% of people)
• Side effects are manageable with dietary changes and lifestyle modifications
• Serious side effects are rare (<1%)
• Starting low and going slow minimizes side effects
• Most people find side effects are worth the significant weight loss results

Don't let fear of side effects prevent you from trying semaglutide. With proper management and support, most people tolerate the medication well and achieve life-changing weight loss results.

Ready to Start Semaglutide with Expert Support?

Our licensed providers specialize in GLP-1 medications and will help you minimize side effects, optimize your dose, and achieve your weight loss goals safely and effectively. Schedule a consultation today.

Medical Disclaimer: This content is for educational purposes only and does not constitute medical advice. Always consult with your healthcare provider about side effects and management strategies. Seek immediate medical attention for severe or concerning symptoms.