Three medicines, three different signals, and the differences are worth knowing. This page describes what separates them. It does not compare them for you, and it does not say which one anybody should be on.
Loopa does not prescribe, dispense or recommend any medication. Which medicine suits you is a conversation with your prescriber.
The short version
| Medicine | What it acts on | How often |
|---|---|---|
| Liraglutide | GLP-1 | Daily |
| Semaglutide | GLP-1 | Weekly, or daily as a tablet |
| Tirzepatide | GLP-1 and GIP | Weekly |
Each is sold under more than one brand name, and the approved uses differ between brands of the same molecule. The prescribing information for each is the authority on what it is approved for and what it warns about (FDA labeling, via openFDA).
What "acts on GIP as well" means
GIP is a second gut hormone released when you eat. Tirzepatide activates both receptors; the others activate GLP-1 alone. Whether that produces a different result for a particular person is a clinical question, and the answer is not the same for everybody.
Where the two have been compared directly in a population, the numbers have differed. In people treated for weight recurrence after a sleeve, mean weight loss at six months was 10.3% with semaglutide and 15.5% with tirzepatide (Jamal M et al., Obesity Surgery, 2024 · doi:10.1007/s11695-024-07137-0). A 2025 meta-analysis of eight studies and 964 patients found total weight loss of −10.97% and −13.63% respectively (Osorio Manyari AA et al., Obesity Surgery, 2025 · doi:10.1007/s11695-025-08414-2).
Those are averages in a specific population after a specific operation. They are not a prediction about you, and a bigger average is not automatically the better choice for any individual: tolerability, cost, availability, other conditions and what your prescriber is treating all bear on it.
Daily against weekly
A daily medicine and a weekly one feel different to live with. A weekly one has a rhythm: many people find the days just after a dose differ from the days before the next. A daily one is steadier and asks to be remembered every day.
Neither is better. They are different shapes of the same commitment, and Loopa records either.
What is the same
The common adverse effects are gastrointestinal across the class, and appear in the adverse-reaction sections of the labels: nausea, vomiting, diarrhea and constipation (WEGOVY prescribing information, section 6.1).
The pattern after stopping is also shared. In a randomized withdrawal trial, people who stopped regained a substantial part of what they had lost (Wilding JPH et al., Diabetes, Obesity and Metabolism, 2022 · doi:10.1111/dom.14725).
And the body-composition question is shared. In the SURMOUNT-1 substudy, about 75% of the weight lost was fat mass and about 25% lean mass, for tirzepatide and placebo alike (Look M et al., Diabetes, Obesity and Metabolism, 2025 · doi:10.1111/dom.16275). That is the reason protecting muscle gets its own page.
How Loopa helps
Loopa does not have a favorite. It records what you are on and what happens.
- Name your compound yourself. Loopa has no medicine catalog to pick from and validates nothing against a dosing reference. You type what you are taking.
- One protocol per medicine, and more than one at once is normal. Health › Protocols.
- The level chart is a shape, not an amount. Where a published half-life exists for what you named, Loopa can draw the rise and fall in relative units, labeled estimated. It is there to make a weekly rhythm visible.
Related
- GLP-1 medicines explained
- Titration, and why doses change over time
- Protecting muscle while losing weight
- Coming off a GLP-1
Where this comes from
Everything on this page is drawn from published clinical guidelines, regulatory labeling and peer-reviewed research, cited above. The full list, with a link to every original, is at loopahealth.app/sources. Loopa does not give medical advice. It does not decide whether a medicine is right for you, does not recommend one over another, and never sets a dose. Your prescriber does all three.
