GLP-1 medications explained
Semaglutide and tirzepatide mimic a gut hormone to reduce appetite. Here's the mechanism, the trial data, how titration affects your bill, and why oral formats aren't equivalent.
GLP-1 receptor agonists mimic a hormone your gut already releases after you eat. They slow gastric emptying, increase satiety, and reduce the food-noise that drives overeating. That's the whole mechanism — the rest is dose, format, and price.
The two molecules that matter
| Semaglutide | Tirzepatide | |
|---|---|---|
| Brand names | Ozempic, Wegovy | Mounjaro, Zepbound |
| Mechanism | GLP-1 agonist | GLP-1 + GIP dual agonist |
| Trial weight loss | ~14.9% over 68 weeks (STEP-1) | up to ~20.9% over 72 weeks (SURMOUNT-1) |
| Compounded cost | $149–$299/mo | $259–$549/mo |
| Typical choice | First-line, cheaper | More potent, costs more |
How titration works
You start low (typically 0.25mg semaglutide weekly) and step up every 4 weeks to manage GI side effects. This matters financially: providers that charge more at higher doses mean your bill climbs as you titrate. Flat-rate providers don't. See the pricing matrix →
Oral vs injectable
Several providers now offer oral tablets or sublingual drops. They're genuinely useful if you're needle-averse — but be clear-eyed: oral and sublingual GLP-1 absorption is pharmacologically weaker and less consistent than subcutaneous injection, and the compounded oral formats have far less evidence behind them. Eli Lilly's lawsuit against Henry Meds specifically targets oral tirzepatide on the grounds that no study establishes it as safe or effective in that format.