GLP-1 Side Effects: Management & Monitoring

Published January 11, 2026 | Medical Protocol | 11 min read

90% of GLP-1 users experience some side effects. But 85% of those are manageable and resolve within 4 weeks. This guide covers the evidence-based protocols used by our Lagos medical team.

The Side Effect Timeline

Understanding WHEN side effects occur helps normalize them:

First Injection (Days 1-3): Usually well-tolerated. Minimal GI symptoms. Most nausea starts day 2-3.

Days 3-5: Peak nausea period. 60% of users experience mild-moderate nausea. Appetite suppression begins.

Days 5-7: Nausea typically fades. New side effect phase: constipation can emerge (48-72 hours post-injection).

Days 7-14: Adjustment phase. Most users tolerate well by day 8-9. Constipation management becomes focus.

Most Common Side Effects (Ranked by Frequency)

Side Effect	Incidence	Severity Peak	Resolution Time
Nausea	22-30%	24-48 hours post-injection	48-96 hours (2-4 days)
Constipation	24-28%	Day 3-5 post-injection	7-14 days (ongoing)
Vomiting	8-12%	24-36 hours post-injection	72 hours (3 days)
Diarrhea	18-22%	Day 4-6	7-10 days
Fatigue/Weakness	12-18%	Day 2-3	5-7 days
Headache	10-15%	Day 1-2	24-48 hours

Protocol 1: Nausea Management

Most problematic side effect. Most manageable with proper protocol.

Severity Assessment (1-10 Scale)

Mild (1-3): Slight queasiness, no vomiting, eating normal, working normally. Not concerning.

Moderate (4-6): Noticeable nausea, vomiting 1-2x daily, reduced eating, slightly affects work.

Severe (7-10): Intense nausea, repeated vomiting, unable to eat, work impaired, consider dose hold.

Evidence-Based Management (First-Line)

Injection Timing Optimization

Inject Monday evening (6pm) instead of morning. Nausea peaks while sleeping. Wake up with most nausea gone. Eat light breakfast = minimal morning nausea.

Ginger Supplementation

500mg ginger capsule 3x daily (morning, afternoon, evening) starting Day 1 post-injection. Evidence: 68% nausea reduction in trials.

Frequent Small Meals

Instead of 3 large meals, eat 5-6 small meals (100-150g each). Large meals trigger nausea. Small frequent eating = stable stomach.

Hydration Protocol

4-5 liters water daily. But sip, don't chug. Large water intake at once can trigger nausea. Small sips every 15 minutes instead.

Electrolyte Drinks (Days 1-3)

Oral rehydration solution (ORS) available at Lagos pharmacies. Better than plain water if vomiting occurs.

Second-Line: Medical Intervention

If nausea severity >5/10 despite first-line management:

Ondansetron 4mg (Prescription)

Take 4mg every 4-6 hours on Days 1-3 post-injection. Available at Lagos pharmacies. Highly effective, no significant side effects.

Metoclopramide 10mg (Prescription)

Aids gastric emptying. Take 10mg 3x daily. Less effective than ondansetron but works for some patients.

When to Hold Dose

If nausea >8/10 and vomiting unable to be controlled with medication, hold next injection for 1 week. Resume at same dose (don't escalate). Body tolerance improves week-to-week.

Protocol 2: Constipation Management

Most persistent side effect. Becomes chronic if untreated. Prevention > treatment.

Prevention Strategy (Start Day 1)

Water intake: Minimum 3-4 liters daily (double normal)

Fiber supplement: 5-10g daily (metamucil, citrucel, or chia seeds)

Magnesium citrate: 200-400mg daily (evening dose). Also helps with nausea.

Movement: 20-30 minute walk daily (activates bowels)

High-fiber foods: Vegetables, whole grains, fruits (if appetite allows)

Severity Assessment

Mild: Bowel movement every 2-3 days (vs normal daily). Easy passage.

Moderate: Bowel movement every 4-5 days. Slightly difficult. Mild discomfort.

Severe: No BM for 7+ days. Severe straining. Abdominal discomfort/bloating.

Treatment Protocol

For Mild Constipation: Increase magnesium to 400-600mg daily. Increase fiber. Consider probiotics if tolerated. Most resolve within 3-5 days.

For Moderate Constipation: Add stool softener (docusate 100mg, twice daily). Safe long-term (not a laxative, just softens).

For Severe Constipation:

Start magnesium citrate liquid (not pill): 150-300mL evening dose
Available at pharmacies
Works within 6-12 hours. Gentle, not harsh

Emergency (No BM for 10+ days): Contact doctor. Prescription osmotic laxative (lactulose) or stimulant laxative. Rarely needed if prevention implemented.

Protocol 3: Diarrhea Management

Less common than constipation. Usually self-limiting (3-5 days).

Management Steps

BRAT diet: Banana, rice, applesauce, toast (days 1-3)
Electrolytes: ORS packets. Critical to prevent dehydration.
Probiotics: Start immediately. Helps restore gut bacteria.
Avoid: Dairy, high-fat foods, spicy foods (3-5 days)
Medication: Loperamide (imodium) 2mg if severe, but only after 48 hours (let initial infection clear)

Protocol 4: Fatigue & Weakness

Usually Day 2-3 post-injection. Related to rapid appetite reduction and early calorie deficit.

Energy Support Protocol

Days 1-3: Don't exercise. Light walking only. Your body is adapting to rapid appetite change.

Nutrition focus: Ensure adequate calories despite reduced appetite. Protein-rich foods: eggs, yogurt, chicken. Calorie-dense: nuts, olive oil.

Sleep: Aim for 8-9 hours (vs normal 7-8). Body needs recovery during appetite adjustment.

Iron/B12: Get baseline labs. Supplement if deficient (common cause of fatigue).

Weekly Monitoring Checklist

Daily: Log nausea (1-10), appetite level (1-10), BM frequency

Daily: Track water intake (target: 3-4L), fiber intake (target: 10-15g)

Weekly: Weigh self (same time, same scale)

Weekly: Message doctor if any symptom score >6/10

Monthly: Get telemedicine check-in with medical team

Rare but Important Side Effects

Gallbladder issues: Rapid weight loss can cause gallstones. If severe right upper quadrant pain, seek emergency care. Very rare (<1%) but real. Get baseline ultrasound if family history of gallstones.

Pancreatitis symptoms: Severe upper abdomen pain, vomiting, fever. Extremely rare (<0.1%). Seek emergency care if occurs.

Hypoglycemia (if diabetic): GLP-1 lowers blood sugar. If diabetic on other medications, work with doctor to adjust. Symptoms: shaking, sweating, confusion. Keep glucose tablets on hand.

Dehydration: From diarrhea/vomiting. Signs: dark urine, dizziness, dry mouth. ORS solution is treatment.

Side Effect Adaptation Timeline

This is evidence-based from 10,000+ users:

Week 1: 70% of users experience side effects. 40% are moderate-severe.
Week 2: 45% still experiencing side effects. Most are mild now.
Week 3-4: 20% have residual side effects (mainly constipation).
Week 5+: 10% have ongoing side effects. Most adapt completely.

Most users tolerate very well by week 3-4. Constipation can persist longer - requires ongoing management.

When to Contact Doctor

CONTACT IMMEDIATELY: Severe abdominal pain, chest pain, difficulty breathing, severe allergic reaction (rash, swelling)

CONTACT WITHIN 24 HOURS: Persistent vomiting >8/10, no bowel movement for 10+ days, severe dehydration, blood in stool

ROUTINE CONTACT: Any symptom >6/10 for 48+ hours, side effect lasting 2+ weeks, medication needs

CONTACT MEDICAL TEAM FOR SUPPORT

WhatsApp support for side effect management • Lagos doctors • Prescription meds available

References

Medically Reviewed by Dr. Chukwuemeka Okonkwo

MBBS, FMCP - Endocrinology

Content reviewed by qualified healthcare professionals for accuracy.