GLP-1 Drug Class Guide: Semaglutide, Tirzepatide, Liraglutide, and More

You have heard of Ozempic, Mounjaro, and Wegovy. They belong to the same drug class, but they are not the same drug, and the differences matter when a doctor decides which one suits you.

This guide organises the full GLP-1 drug class clearly: the original daily injections, the newer once-weekly options, and the oral tablets now available for certain uses. If you are considering starting one of these medicines in Bangkok, check your BMI and baseline metabolic numbers before your consultation. It gives your doctor a useful starting point.

How the GLP-1 Medicine Class Is Organised

GLP-1 receptor agonists mimic glucagon-like peptide-1, a hormone your intestine releases in response to food. They slow gastric emptying, reduce appetite, and prompt insulin release when blood sugar rises. They do not force insulin release when blood sugar is normal, which lowers the risk of dangerous hypoglycaemia compared with some older diabetes drugs.

The class is organised by dosing frequency. Daily agents include liraglutide and oral semaglutide. Weekly agents include subcutaneous semaglutide, tirzepatide, dulaglutide, and exenatide extended-release. For most people with busy schedules in Bangkok, once-weekly dosing is far more practical.

Every approved GLP-1 receptor agonist carries an FDA black-box warning about thyroid C-cell tumours based on rodent studies. This does not mean tumours are common in humans, but these medicines are contraindicated if you have a personal or family history of medullary thyroid carcinoma or MEN2 syndrome. Class-wide cautions also cover acute pancreatitis and gallbladder disease. Those warnings apply regardless of which agent you choose.

Liraglutide was added to the WHO Essential Medicines List in 2025, reflecting its established safety profile and global access priority for adults with type 2 diabetes who also have cardiovascular disease, kidney disease, or obesity.

Semaglutide Brands You Will Hear About

Semaglutide is currently the most widely recognised name in the class, and it appears under several brand names depending on dose and route. Ozempic is the injectable weekly formulation approved for type 2 diabetes. Wegovy is a higher-dose weekly injection approved for chronic weight management. Rybelsus is the oral tablet, taken daily, approved for type 2 diabetes.

An oral Wegovy tablet for weight management received US approval in December 2025. Availability in Thailand should be confirmed at consultation, as Thai FDA registration timelines differ from US approval dates.

Semaglutide’s SELECT trial demonstrated a reduction in cardiovascular events in adults with established cardiovascular disease and overweight or obesity, even without a diabetes diagnosis. That cardiovascular indication matters when a doctor is weighing options for a patient with multiple risk factors. You can review your own cardiovascular risk profile before your visit.

Tirzepatide as a Dual GLP-1 and GIP Agonist

Tirzepatide, sold as Mounjaro for diabetes and Zepbound for weight management, is not a pure GLP-1 agonist. It activates both the GLP-1 and GIP receptors at the same time. GIP, glucose-dependent insulinotropic polypeptide, is a second incretin hormone involved in fat storage and energy balance. Targeting both receptors is why it is called a dual agonist.

The SURMOUNT-5 trial compared tirzepatide directly against semaglutide for weight management, using the maximum tolerated dose of each drug (tirzepatide 10 or 15 mg; semaglutide 1.7 or 2.4 mg), and found greater mean weight reduction with tirzepatide. That does not mean tirzepatide is automatically the right choice for every patient. Individual tolerability, cardiovascular history, cost, and local availability all factor into the decision.

Both Mounjaro and Zepbound are injected once weekly. The same class-wide thyroid and pancreatitis warnings apply to tirzepatide. A physician assessment is required before starting either formulation.

Liraglutide Daily Options

Liraglutide was the first GLP-1 agent approved for weight management, well before semaglutide. Victoza is the diabetes formulation, injected daily. Saxenda is the higher-dose version approved for chronic weight management, also injected daily.

Daily dosing is a real commitment. Most patients find once-weekly agents easier to sustain, but some prefer a daily injection they can time precisely. Liraglutide also has a longer real-world evidence record than the newer agents, which matters in shared decision-making.

Generic liraglutide exists in some markets. As of this review, Thai FDA registration for generic versions should be verified at consultation. Supply of branded liraglutide has been more consistent in Bangkok than that of unbranded alternatives.

Dulaglutide and Other Weekly Diabetes Agents

Dulaglutide, sold as Trulicity, is a once-weekly injectable approved for type 2 diabetes. The REWIND trial demonstrated cardiovascular risk reduction in patients with type 2 diabetes and either established cardiovascular disease or multiple cardiovascular risk factors. That makes dulaglutide one of the few agents with a dedicated cardiovascular outcomes trial supporting its use in a broader diabetes population.

Dulaglutide is delivered via a single-use autoinjector that many patients find easier to handle than a standard pen. HbA1c reduction, your three-month average blood sugar marker, is clinically meaningful with dulaglutide, though available trials suggest the magnitude is generally somewhat lower than with semaglutide.

Earlier Agents Such as Exenatide in Historical Context

Exenatide was the first GLP-1 receptor agonist approved for clinical use. Byetta, the twice-daily formulation, launched in 2005. Bydureon BCise, the once-weekly extended-release version, followed later and remains available in some markets.

Two agents from the class are no longer available. Albiglutide, sold as Tanzeum, was withdrawn by its manufacturer in 2017 for commercial reasons, not safety. Lixisenatide, sold as Adlyxin, was also discontinued. If you see either of these names on a list of GLP-1 drugs, they are not options you can currently access.

For most new patients starting therapy in Bangkok now, weekly semaglutide, tirzepatide, or dulaglutide are the agents most commonly discussed, based on current availability and evidence base.

Pipeline Dual and Triple Agonists in Brief

Two pipeline agents appear frequently in news coverage. Retatrutide is a triple agonist targeting GLP-1, GIP, and glucagon receptors. Phase 2 data showed substantial weight reduction, and phase 3 trials were ongoing as of this review. Orforglipron (brand name Foundayo) is an oral non-peptide GLP-1 agonist approved by the FDA in April 2026 for weight management, notable because it does not require refrigeration. Whether it is registered in Thailand should be confirmed at consultation.

Cagrilintide combined with semaglutide, studied as CagriSema, adds an amylin receptor target on top of GLP-1 action. Phase 3 data for this combination is under review.

Why Pipeline Drugs Are Not Clinic Shortcuts

Orforglipron (Foundayo) received FDA approval in April 2026. Retatrutide has not been approved in any jurisdiction as of this review. CagriSema has an FDA application pending. None of these are approved for clinical use in Thailand as of this review, and Thai FDA registration should be confirmed before assuming availability. Seeking them through unregulated sources carries serious risks: unknown dosing, contamination, and no physician oversight. Off-label prescribing of unapproved investigational drugs is not something a responsible licensed clinic will do. If a source in Bangkok is offering you retatrutide or orforglipron outside a registered clinical trial, that is a red flag.

Getting a GLP-1 Prescription in Bangkok

Under Thai FDA rules, GLP-1 receptor agonists are classified as dangerous drugs requiring a licensed doctor’s prescription. A January 2026 regulatory proposal would move them to special controlled-drug status, tightening that requirement further. This matters if you have been considering buying a slimming pen from a pharmacy without a consultation, which is both legally uncertain and medically unsafe.

The practical path for expats and medical tourists is a same-day consultation at a registered private clinic. Doctor Bangkok can assess your eligibility, review your medical history, check relevant contraindications, and issue a prescription in a single visit. If you cannot get to the clinic, the doctor-on-call service brings a physician to your hotel or condo anywhere in Bangkok within one hour. Full treatment options are detailed on Doctor Bangkok’s dedicated GLP-1 service page.