What a GLP-1 is, and what each one costs
GLP-1 is a hormone your gut releases when you eat. The drugs named after it are copies that last longer, and the reason they work for weight is the same reason they were built for diabetes.
Last updated 2026-08-24 — the prices and figures quoted below
What is a GLP-1?
Glucagon-like peptide-1 is released by the small intestine after a meal. It prompts insulin, suppresses glucagon, slows how fast the stomach empties, and signals fullness to the brain. Your own GLP-1 is broken down within minutes. The drugs are engineered to resist that breakdown, so a weekly injection holds a signal your body sends for a few minutes at a time. That is the whole mechanism, and it explains the side effects as directly as it explains the weight loss: a drug that slows the stomach causes nausea, and one that signals fullness reduces how much someone eats. Of the 12 medications halfrx tracks, 9 act on the GLP-1 receptor: Zepbound (tirzepatide); Wegovy pill (semaglutide); Mounjaro (tirzepatide); Wegovy (semaglutide); Foundayo (orforglipron); Ozempic (semaglutide); Saxenda (liraglutide); Compounded semaglutide (semaglutide); Compounded tirzepatide (tirzepatide). Tirzepatide is the one worth separating out — it acts on GIP as well as GLP-1, which is why it is described as a dual agonist rather than a GLP-1 alone, and why its trial figure sits above the others.
The hormone, in one paragraph
Glucagon-like peptide-1 is released by the small intestine after a meal. It prompts insulin, suppresses glucagon, slows how fast the stomach empties, and signals fullness to the brain. Your own GLP-1 is broken down within minutes. The drugs are engineered to resist that breakdown, so a weekly injection holds a signal your body sends for a few minutes at a time.
That is the whole mechanism, and it explains the side effects as directly as it explains the weight loss: a drug that slows the stomach causes nausea, and one that signals fullness reduces how much someone eats.
Which drugs are GLP-1s, and which are something else
Of the 12 medications halfrx tracks, 9 act on the GLP-1 receptor: Zepbound (tirzepatide); Wegovy pill (semaglutide); Mounjaro (tirzepatide); Wegovy (semaglutide); Foundayo (orforglipron); Ozempic (semaglutide); Saxenda (liraglutide); Compounded semaglutide (semaglutide); Compounded tirzepatide (tirzepatide).
Tirzepatide is the one worth separating out — it acts on GIP as well as GLP-1, which is why it is described as a dual agonist rather than a GLP-1 alone, and why its trial figure sits above the others.
The rest are not GLP-1s at all and are often confused for them: Qsymia (phentermine, topiramate); Contrave (naltrexone, bupropion); Phentermine (phentermine). They work by different mechanisms, cost far less, and lose less weight in their own trials.
What each one did in its own trial
Mean weight loss in the trial each label cites: Zepbound 20.9%, Wegovy pill 16.6%, Mounjaro 15%, Wegovy 14.9%, Foundayo 14.7%, Ozempic 12%.
These are not comparable head to head. Each figure comes from a separate trial with a different population, a different duration and a different endpoint — none of these drugs was run against another. A higher number is a different study, not a better result, and any page that ranks them as though they raced is inventing a race.
What they cost, which is the part nobody explains
Verified cash prices on this site run from $98 a month for Qsymia to $499 for Mounjaro — a spread of $401 a month for treatment in the same category.
The figure that matters is the maintenance price, not the advertised one: the starting dose is not the dose anyone stays on, and an introductory rate covers a month or two of a course measured in years. 4 of the priced options are compounded rather than FDA approved, which is a legal status rather than a quality claim, and they sit at the cheap end for that reason.
Questions
- Is Ozempic a GLP-1?
- Yes. Ozempic is semaglutide, a GLP-1 receptor agonist, approved for type 2 diabetes rather than for weight. Wegovy is the same molecule approved at higher doses for weight management. halfrx records Ozempic at $199 a month cash. Prescribing Ozempic for weight alone is off-label, which is legal and common and is not the same thing as approved.
- Is tirzepatide a GLP-1?
- Partly. Tirzepatide activates GIP as well as GLP-1, so it is a dual agonist. It is sold as Zepbound for weight and Mounjaro for diabetes — the same molecule under two labels, at prices that differ.
- Do you have to stay on a GLP-1 forever?
- That is a question for a prescriber, not for a comparison site. What the pricing shows is that the manufacturers treat it as ongoing: prices are structured around continuing refills, and the conditional self-pay rates are conditional on refilling on schedule.
Every figure above is read from the drug's own card, which records where it came from and the date it was verified. Clinical statements are quoted from the FDA label or the named trial, never interpreted. Information only, not medical advice.