Fat Loss & Metabolism

Semaglutide

Ozempic · Wegovy · Rybelsus · GLP-1 agonist

FDA-approved mainstream subQ injection / oral tablet

What it is

Semaglutide is a long-acting analog of GLP-1, a hormone your gut releases after eating. The synthetic version is engineered to resist breakdown so a single weekly injection produces sustained appetite suppression and improved insulin function. FDA-approved for type 2 diabetes (Ozempic, 2017), chronic weight management (Wegovy, 2021), and cardiovascular risk reduction (2024).

How it works

Semaglutide does several things simultaneously:

Slows stomach emptying — food sits longer, so you feel full faster and longer.
Acts on hunger centers in the brain — reduces food-seeking behavior and "food noise."
Improves insulin sensitivity — helps cells respond properly to insulin.
Stimulates insulin release — but only when blood sugar is high, so hypoglycemia risk is low.

The result is reduced calorie intake driven by reduced appetite, not willpower. People typically lose 14–15% of body weight in clinical trials, and far more if combined with proper diet and exercise.

Benefits

Significant weight loss (~15% body weight in 68 weeks at 2.4 mg dose)
Improved blood glucose control and HbA1c
Cardiovascular event reduction (heart attack, stroke risk)
Reduced inflammation markers
Lower blood pressure and improved lipids
Reduced "food noise" and addictive eating patterns
Possible benefits for kidney disease and chronic inflammation

Timeline

Week 1–4: Appetite suppression begins. Common nausea during titration.
Week 4–8: 3–5% weight loss; "food noise" clearly reduced.
Week 12–20: 8–12% weight loss; need active resistance training to preserve muscle.
Week 60+: Peak weight loss (~15% body weight in trials). Plateau hits around month 14.

Dosing & titration

Starting dose0.25 mg subQ once weekly

Standard titration0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg, increasing every 4 weeks

Max weight-loss dose2.4 mg/week (Wegovy label)

Diabetes doseOften 0.5–1.0 mg/week (Ozempic label)

Oral formRybelsus, 7–14 mg daily on empty stomach

When to titrate upOnly after 4 weeks at current dose with tolerable side effects. If nausea is rough, stay at the same dose another month.

Side effects & risks

Nausea (most common, especially during titration)
Vomiting, diarrhea, constipation
Acid reflux and burping ("sulfur burps")
Fatigue, decreased exercise tolerance
Hair shedding (usually temporary)
Significant muscle loss without protein and resistance training
Gallstones from rapid weight loss
Rare: pancreatitis, gastroparesis

Critical: Eat 1g of protein per pound of body weight and lift 3+ days/week, or you'll lose ~30–40% of weight loss as muscle. Black-box warning for medullary thyroid carcinoma in animals; contraindicated in MEN-2 history. Don't combine with insulin or sulfonylureas without close glucose monitoring.

Typical price

$200–$1,400/mo Compounded semaglutide: $200–$400/mo. Branded (Ozempic/Wegovy) without insurance: $1,000–$1,400/mo. Compounded availability has narrowed sharply since 2024 FDA enforcement.

Studies

Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1) — The pivotal trial. 14.9% weight loss at 68 weeks vs. 2.4% placebo. NEJM New England Journal of Medicine, 2021
Two-year effects of semaglutide in adults with overweight or obesity (STEP 5) — Showed weight-loss durability over 104 weeks. Nature Medicine Nature Medicine, 2022
STEP 4: Effect of continued weekly semaglutide vs placebo on weight maintenance — Demonstrated rebound weight gain when discontinued. JAMA JAMA, 2021
Once-Weekly Semaglutide in Adolescents with Obesity — Pediatric efficacy data. NEJM New England Journal of Medicine, 2022

Educational reference only. Not medical advice. Semaglutide is FDA-approved but requires a prescription and ongoing medical monitoring.