Semaglutide
Reviewed by Fat Man in the Arena · Updated March 2026
Key Takeaway
Semaglutide is a GLP-1 receptor agonist originally developed for type 2 diabetes that has demonstrated significant weight loss effects in clinical trials. It is sold under the brand names Ozempic (diabetes) and Wegovy (weight management).
How it works
Semaglutide mimics the GLP-1 hormone, which is released after eating. It slows gastric emptying, reduces appetite by acting on brain regions that control hunger, and improves insulin sensitivity. The result is reduced caloric intake and improved metabolic markers.
Benefits
- Average 14.9% body weight loss over 68 weeks (STEP 1 trial)
- Reduced appetite and food cravings
- Improved cardiovascular risk factors
- Better blood sugar control
- Reduced waist circumference
- Oral formulation now available (Rybelsus / oral Wegovy)
Side effects
- Nausea (most common, typically improves over time)
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain
- Headache
- Rare: pancreatitis, gallbladder issues
- Potential muscle mass loss alongside fat loss
Dosing protocol
Typical Dose
0.25 mg to 2.4 mg weekly (injection)
Frequency
Once weekly subcutaneous injection
Cycle Length
Ongoing — weight regain common after discontinuation
Dose is titrated up gradually over 16-20 weeks to minimize GI side effects. Start at 0.25 mg/week for 4 weeks, then increase. The FDA-approved weight loss dose is 2.4 mg/week (Wegovy).
Key research
Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1)
New England Journal of Medicine (2021) — PubMed
Participants lost an average of 14.9% of body weight over 68 weeks compared to 2.4% with placebo. One-third of participants lost more than 20% of their body weight.
Two-Year Effects of Semaglutide in Adults with Overweight or Obesity (STEP 5)
Nature Medicine (2022) — PubMed
Sustained weight loss of 15.2% at 104 weeks, demonstrating long-term efficacy when treatment is continued.
FDA status
FDA Approved for: Type 2 diabetes (Ozempic), chronic weight management (Wegovy)
Frequently asked questions
In the STEP 1 clinical trial published in the New England Journal of Medicine in 2021, participants taking 2.4 mg semaglutide weekly lost an average of 14.9% of their body weight over 68 weeks. About one-third of participants achieved 20% or greater weight loss compared to placebo.
Compare Semaglutide
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Semaglutide vs Survodutide: GLP-1 vs GLP-1/Glucagon Dual Agonist
Ozempic vs Wegovy: Same Drug, Different Doses — What You Need to Know
Semaglutide vs Tirzepatide vs Retatrutide: Complete GLP-1 Comparison
Compounded vs Brand-Name Semaglutide: Price, Safety, and Legality
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Medical Disclaimer: This content is for informational and educational purposes only. It is not intended as medical advice or a substitute for professional medical consultation, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide protocol.