Most people starting semaglutide or tirzepatide experience some side effects. Most are gastrointestinal, most settle, and most are manageable. A few are not, and knowing which is which is the point of this page.
None of this replaces talking to your provider. If something worries you, call us — that is included in what you are paying for.
Medically reviewed by Kent Cohen, MD, FACEP — Medical Director, Balanced Bodies: Longevity + Wellness Clinic. Last reviewed October 2026.
Common, and usually temporary
Nausea. The most frequent complaint, typically worst in the days after starting or after a dose increase, and usually easing as you adjust.
Constipation. Very common and often underestimated. These medications slow gastric emptying, and eating much less means less fibre and often less fluid.
Diarrhoea, reflux, burping, early fullness. All reported and all usually manageable.
Fatigue. Often a consequence of eating considerably less rather than a direct drug effect, and frequently a sign that intake has dropped too far too fast.
Injection site reactions. Mild redness or itching that settles.
What usually helps
Slow the titration. Most side effects track dose increases. There is rarely a good reason to climb quickly, and we would generally rather hold you at a tolerable dose that is working than push to a higher one that makes you miserable.
Smaller meals, eaten slowly. Your stomach is emptying more slowly. Large meals sit.
Reduce fat and fried food temporarily. These are the hardest to tolerate when gastric emptying is slowed.
Fluids and fibre, deliberately. For constipation this is usually the fix, and it needs to be deliberate because thirst cues drop along with appetite.
Stop eating when you are full. Simple, and routinely ignored. Pushing past fullness on a GLP-1 is the most reliable way to feel sick.
On a genuinely rough week, a hydration or B-vitamin IV or injection can help you through it. Patients who live close by sometimes walk in for exactly that.
Call us promptly
Contact your provider, or seek urgent care, if you experience:
- Severe or persistent abdominal pain, particularly pain radiating to your back, which can indicate pancreatitis
- Pain in the upper right abdomen, fever, or yellowing of the skin or eyes, which can indicate gallbladder problems
- Persistent vomiting, or an inability to keep fluids down
- Signs of dehydration — dizziness on standing, markedly reduced urination, confusion
- A lump or swelling in your neck, hoarseness, or difficulty swallowing
- Symptoms of low blood sugar, particularly if you also take insulin or a sulfonylurea
- Changes in vision, particularly if you have diabetic retinopathy
- Any significant mood change, including new or worsening low mood
This list is not exhaustive. Anything that concerns you is worth a call.
Side effects you should not simply tolerate
There is a culture around these medications of treating misery as the price of progress. We do not agree with it.
If you are consistently unable to eat, losing weight very rapidly, or feeling unwell most of the time, the dose is wrong for you. Rapid loss driven by inability to eat costs disproportionate lean mass, which undermines the result you are working toward. That is a reason to adjust, not to endure.
How this is monitored here
Side effects and tolerance are part of every visit, alongside your protein intake and your InBody scan. Dose decisions are made by a provider who has seen your numbers, not by a fixed titration schedule applied to everyone.
Book a free consultation or call (678) 919-4845.
Further reading
FDA: Human Drug Compounding · NIDDK: Weight Management
The semaglutide and tirzepatide we dispense are compounded by licensed 503A pharmacies and are not FDA-approved finished products. This article is general information and not medical advice. Individual responses vary.
