Public conversation about this drug class has collapsed into two brand names, both of which are semaglutide or tirzepatide wearing different labels. The actual field is wider, older and more varied than that.
Some of what follows you will never be offered. It is worth knowing anyway, because formularies have long memories and step therapy frequently routes people through drugs the internet stopped discussing in 2021.
The directory
| Molecule | Brands | Schedule | Licensed for | Approx. weight loss |
|---|---|---|---|---|
| Tirzepatide | Mounjaro, Zepbound | Weekly injection | T2D; obesity; sleep apnoea | ~21% |
| Semaglutide | Ozempic, Wegovy | Weekly injection | T2D; obesity; CV risk; CKD; MASH | ~15% |
| Semaglutide (oral) | Rybelsus | Daily tablet | T2D | Lower |
| Liraglutide | Victoza, Saxenda | Daily injection | T2D; obesity | ~8% |
| Dulaglutide | Trulicity | Weekly injection | T2D; CV risk in T2D | Modest |
| Exenatide | Byetta, Bydureon | Twice daily / weekly | T2D | Modest |
2005
Year exenatide became the first GLP-1 agonist approved — the class is older than the hype
5
Distinct molecules in current clinical use across the class
~13×
Ratio between the priciest list prices and the cheapest older agents in this table
The two that dominate
Tirzepatide is the most effective, and the only one that activates the GIP receptor as well as GLP-1. Full treatment in tirzepatide explained.
Semaglutide has the broadest licence — diabetes, obesity, cardiovascular risk, kidney disease and liver disease — and the deepest outcome evidence. Full treatment in semaglutide explained.
Choosing between them is covered in semaglutide versus tirzepatide; moving between them in switching between GLP-1s.
The older agents, and why they persist
Liraglutide (Victoza, Saxenda). A daily injection, and the drug that established this class for weight management in the SCALE trial at around eight percent. It is still the only GLP-1 besides Wegovy licensed for adolescents from age 12 — see GLP-1s for teenagers. Generic liraglutide has begun to appear, which makes it the cheapest genuine GLP-1 available to many people.
Dulaglutide (Trulicity). A weekly injection from Eli Lilly, developed for glycaemic control with a cardiovascular indication in type 2 diabetes. Its weight effect is modest. Widely prescribed, rarely discussed outside diabetes clinics.
Exenatide (Byetta, Bydureon). The original, approved in 2005 and derived from a peptide found in Gila monster venom. Largely superseded, and useful mainly as a reminder that this class did not appear in 2021.
What is nearly here
Orforglipron. A non-peptide, small-molecule oral GLP-1. The significance is manufacturing: peptides are expensive and complex to produce, and a small molecule is neither. If it delivers, it changes the supply and price picture rather than just the efficacy one. See orforglipron.
Retatrutide. Adds glucagon receptor agonism to GLP-1 and GIP — a triple agonist, targeting effect sizes beyond tirzepatide.
CagriSema. Semaglutide combined with cagrilintide, an amylin analogue, which is a different hormonal axis again.
Higher-dose oral semaglutide for obesity — see the obesity pill.
The state of that pipeline is in the next wave, and the drugs being developed specifically to protect muscle alongside them are in muscle preservation trials.
What is not in this class
Worth stating, because these get grouped together carelessly.
Phentermine, Qsymia, Contrave, orlistat. Effective to varying degrees, entirely different mechanisms, and compared in Ozempic alternatives.
Metformin. Not an incretin. Cheap, useful, modest for weight.
SGLT2 inhibitors — dapagliflozin, empagliflozin. Different class, frequently co-prescribed, and relevant here mainly because they compound dehydration risk — see dehydration and your kidneys.
Anything sold as a GLP-1 supplement. See the “natural Ozempic” question.
The first drug in this class was approved in 2005, from a compound found in lizard venom. Nothing about the last three years was sudden except the marketing.
What the whole class shares
Whichever molecule you end up on, these hold:
- The same absolute contraindications — medullary thyroid carcinoma and MEN2
- The same broad side effect profile, dominated by gastrointestinal effects
- The same escalation logic — start below the effective range, climb slowly, see the dose charts
- The same muscle loss risk if protein and resistance training are neglected
- The same behaviour on stopping: weight returns
The practical use of this page
If you have been offered something that is not one of the two famous ones, it is probably on this list, probably older, and probably being offered because of your formulary rather than your physiology.
That is worth knowing before you accept it, and worth knowing before you refuse it — liraglutide at eight percent is a real drug, and for a great many people it is the one that is actually available.