Semaglutide is a GLP-1 receptor agonist—a medication that mimics a hormone your body naturally produces. It was originally developed for Type 2 diabetes but became a breakthrough weight loss treatment when clinical trials showed dramatic results.
Semaglutide works through four main pathways:
1. Brain signals: It acts on your hypothalamus to reduce hunger signals and increase satiety signals. You feel genuinely satisfied with less food.
2. Slower digestion: Food stays in your stomach longer, creating a prolonged feeling of fullness after meals.
3. "Food noise" reduction: Many users report that the constant mental chatter about food—planning meals, fighting cravings—goes quiet. This is often described as the most life-changing effect.
4. Blood sugar regulation: It helps your body release insulin more effectively, keeping blood sugar stable and reducing energy crashes.
The STEP trials established semaglutide's effectiveness:
| Trial | Population | Result |
|---|---|---|
| STEP 1 | Adults without diabetes | 14.9% weight loss vs 2.4% placebo |
| STEP 2 | Adults with Type 2 diabetes | 9.6% weight loss vs 3.4% placebo |
| STEP 5 | 2-year follow-up | 15.2% maintained at 2 years |
| STEP TEENS | Adolescents 12-17 | 16.1% BMI reduction |
Semaglutide follows a titration schedule—you start low and increase gradually:
Important: The first 8 weeks are for adjustment, not results. Don't panic if you don't see dramatic changes at 0.25 or 0.5 mg—that's expected.
Most common (and usually temporary):
Serious risks (rare): Pancreatitis, gallbladder issues, and a black-box warning about thyroid C-cell tumors (observed in rodent studies). Anyone with personal or family history of medullary thyroid cancer should not take semaglutide.
Good candidates:
Not appropriate for:
Tirzepatide (Zepbound/Mounjaro) is the newer option, targeting two receptors instead of one. In head-to-head trials, tirzepatide produced about 47% more weight loss. However, semaglutide is more affordable (especially compounded), has more long-term safety data, and works extremely well for most people.
Many people start with semaglutide and only consider switching if they plateau.
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