The active ingredient in Ozempic and Wegovy. It mimics a natural gut hormone (GLP-1) that tells your brain you're full and slows down how fast food leaves your stomach. Extremely effective for weight loss and improving metabolic health overall.
What to Expect
Week 1–2
Reduced appetite noticeable within days. Possible nausea as body adjusts. Early satiety at meals. Start at low dose to minimize GI side effects.
Week 3–6
Significant appetite suppression. Weight loss of 3-5% body weight. Reduced food noise and cravings. GI side effects typically improving as dose stabilizes.
Week 8+
Substantial weight loss (10-15%+ of body weight). Improved metabolic markers — HbA1c, triglycerides, blood pressure. Reduced cardiovascular risk markers.
Common Side Effects
Scientific Overview
Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist with 94% homology to native GLP-1. Structural modifications include an Aib substitution at position 8 (DPP-4 resistance) and a C-18 fatty diacid chain enabling albumin binding, yielding a half-life of ~7 days. It acts on pancreatic β-cells to enhance glucose-dependent insulin secretion, suppresses glucagon, delays gastric emptying, and acts on hypothalamic GLP-1 receptors to reduce appetite. The STEP trials demonstrated 14.9% mean body weight reduction at 68 weeks with 2.4mg weekly dosing.
Dosing
Start at 0.25 mg per week and gradually increase to 1-2.4 mg per week over several months. Meant for long-term use.
Practical Guide
Reconstitution
Pre-filled pens (Ozempic/Wegovy) require no reconstitution. Compounded vials: follow pharmacy instructions for dilution.
Storage
Unopened pens: refrigerate. In-use pens: room temperature up to 56 days (Ozempic) or 28 days (Wegovy). Protect from heat.
Injection Sites
Subcutaneous injection. Rotate injection sites weekly. Use pen needle as directed. Compounded versions use insulin syringe.
Timing
Inject once weekly on the same day each week. Any time of day. Choose a day when mild nausea won't disrupt plans.
Food
No food timing requirement for injection. Eat slowly and stop when full — overeating causes severe nausea.
Benefit Profile
Medical Considerations
Contraindications
- ✕Personal or family history of medullary thyroid carcinoma
- ✕Multiple Endocrine Neoplasia syndrome type 2 (MEN2)
- ✕Pregnancy/nursing
- ✕History of pancreatitis
- ✕Severe gastroparesis
Drug Interactions
Recommended Monitoring
- →HbA1c every 3 months
- →Renal function (BUN, creatinine)
- →Lipase/amylase if pancreatitis symptoms
- →Heart rate monitoring
- →Gallbladder symptoms
This information is for educational purposes only. Always consult a qualified healthcare provider before starting any peptide protocol.
Published Research
Subcutaneously administered tirzepatide vs semaglutide for adults with type 2 diabetes: a systematic review and network meta-analysis of randomised controlled trials.
Efficacy and Safety of Semaglutide for Weight Loss in Obesity Without Diabetes: A Systematic Review and Meta-Analysis.
Semaglutide for type 2 diabetes mellitus: A systematic review and meta-analysis.
Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial.
Semaglutide 2·4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2): a randomised, double-blind, double-dummy, placebo-controlled, phase 3 trial.
The effect of semaglutide 2.4 mg once weekly on energy intake, appetite, control of eating, and gastric emptying in adults with obesity.
Efficacy and safety of once-weekly semaglutide 2·0 mg versus 1·0 mg in patients with type 2 diabetes (SUSTAIN FORTE): a double-blind, randomised, phase 3B trial.
Efficacy and safety of once-weekly semaglutide 1.0mg vs once-daily liraglutide 1.2mg as add-on to 1-3 oral antidiabetic drugs in subjects with type 2 diabetes (SUSTAIN 10).
Semaglutide versus dulaglutide once weekly in patients with type 2 diabetes (SUSTAIN 7): a randomised, open-label, phase 3b trial.
Efficacy and safety of once-weekly semaglutide monotherapy versus placebo in patients with type 2 diabetes (SUSTAIN 1): a double-blind, randomised, placebo-controlled, parallel-group, multinational, multicentre phase 3a trial.