How It Works
Semaglutide is a synthetic version of glucagon-like peptide-1 (GLP-1), a hormone naturally produced in the gut after eating.
When you eat, natural GLP-1 is released to stimulate insulin production and tell your brain you are full. However, natural GLP-1 breaks down in the body within minutes. Semaglutide is structurally modified to resist this breakdown, giving it a half-life of roughly seven days for once-weekly dosing.
Semaglutide operates through three primary mechanisms:
- Neurological: It crosses the blood-brain barrier and binds to receptors in the hypothalamus, directly reducing appetite and cravings (often referred to as "food noise").
- Gastrointestinal: It delays gastric emptying. Food stays in your stomach longer, physically keeping you full.
- Metabolic: It stimulates insulin secretion and suppresses glucagon release in a glucose-dependent manner, stabilizing blood sugar levels.
Benefits
- Average 14.9-15.3% body weight loss in STEP trials (2.4mg dose, 68 weeks)
- 20% reduction in major cardiovascular events (SELECT trial) — proven heart protection
- Significant improvements in insulin sensitivity and HbA1c
- Reduction in systemic inflammation (CRP)
- Available in both injectable and oral (Rybelsus) formulations
- The most long-term safety data of any GLP-1 agonist
Side Effects
- Nausea (most common, affecting up to 44% of users, peaks 24-48 hours after injection)
- Fatigue (often a byproduct of reduced caloric intake)
- Constipation or diarrhea (altered gastric emptying)
- Acid reflux (if eating large or high-fat meals)
- Injection site reactions (mild)
Dosing Protocol
| Phase | Duration | Weekly Dose | Purpose |
|---|---|---|---|
| Initiation | Weeks 1-4 | 0.25mg | Acclimate the body, minimize nausea |
| Step 1 | Weeks 5-8 | 0.5mg | Begin therapeutic escalation |
| Step 2 | Weeks 9-12 | 1.0mg | First significant clinical dose |
| Step 3 | Weeks 13-16 | 1.7mg | Transition to maintenance |
| Maintenance | Week 17+ | 2.4mg | Maximum therapeutic dose |
Many patients achieve their target weight loss at 1.0mg or 1.7mg and do not need to escalate to 2.4mg. Dosing should always be guided by clinical response and side effect tolerance.
What You Will Need
- Semaglutide prescription (via telehealth clinic, endocrinologist, or PCP)
- Pre-filled injection pens (brand Wegovy/Ozempic) or compounded vials with insulin syringes
- Alcohol swabs
- Sharps container
Mitigating Side Effects
- Stay hydrated: Drink significantly more water than usual
- Prioritize protein: Focus on high-protein, nutrient-dense foods to preserve lean muscle
- Eat smaller meals: Because the stomach empties slower, large meals cause severe discomfort
- Do not rush titration: If you experience severe nausea at 0.5mg, do not move up to 1.0mg until it subsides
- Resistance training: Essential to prevent muscle loss during rapid weight loss