GLP-1 Agonists
Everything you need to know about GLP-1 receptor agonist medications — how they work, which ones are available, and how they compare.
GLP-1 receptor agonists are a class of injectable medications that mimic the gut hormone GLP-1. They're used for type 2 diabetes and weight management. The most well-known are semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro).
Good for you if: You want to understand the full landscape of GLP-1 medications before discussing options with your doctor, or you're comparing different drugs in this class.
Dive deeper into the researchCommon side effects
- GI side effects (nausea, vomiting, diarrhoea) are common across all GLP-1 drugs
- Muscle loss is a significant concern — requires active prevention
- Rare but serious: pancreatitis, gallbladder disease, thyroid C-cell risk
What do GLP-1 agonists do?
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after you eat. It tells your brain you're full, signals your pancreas to release insulin, and slows down digestion. GLP-1 agonists are synthetic versions of this hormone that last much longer than the natural version.
The result: better blood sugar control, reduced appetite, gradual weight loss, and cardiovascular protection. These medications have transformed how we treat type 2 diabetes and obesity.
Who are they for?
- Type 2 diabetes — when metformin alone isn't enough
- Obesity — BMI ≥30, or ≥27 with weight-related conditions
- Cardiovascular protection — proven to reduce heart attacks and strokes in at-risk patients
How are they taken?
Most GLP-1 agonists are injected — either daily or weekly, depending on the specific drug. One oral version exists (oral semaglutide, sold as Rybelsus).
Available GLP-1 drugs compared
| Drug | Brand(s) | Frequency | Weight loss | India availability |
|---|---|---|---|---|
| Semaglutide | Ozempic, Wegovy, Rybelsus | Weekly injection or daily oral | 15–17% | Yes |
| Tirzepatide | Mounjaro, Zepbound | Weekly injection | Up to 22.5% | Growing |
| Liraglutide | Victoza, Saxenda | Daily injection | 5–8% | Yes |
| Dulaglutide | Trulicity | Weekly injection | 3–5 kg | Yes |
| Retatrutide | Not yet branded | Weekly injection | Up to 24% | Not yet (Phase 3) |
Availability in India
The most widely available GLP-1 drugs in India are Ozempic (semaglutide), Victoza (liraglutide), Trulicity (dulaglutide), and Mounjaro (tirzepatide). Rybelsus (oral semaglutide) is also available. All require a prescription.
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HbA1c, fasting insulin, body composition, and more — monitored over time so you can see if your protocol is working.
Get early accessFrequently Asked Questions
Which GLP-1 drug produces the most weight loss?
Currently, tirzepatide (Mounjaro) produces the most weight loss at ~22.5%. Semaglutide (Wegovy) follows at 15–17%. Retatrutide, if approved, may exceed both at ~24%. Dulaglutide and liraglutide produce less weight loss.
Are GLP-1 drugs safe long-term?
The oldest GLP-1 drugs have 15+ years of safety data. Long-term risks are well-characterised: rare pancreatitis, increased gallstone risk with weight loss, and a theoretical thyroid concern based on rodent studies. For most patients, benefits significantly outweigh risks.
Can I take a GLP-1 drug without diabetes?
Yes, if prescribed by a doctor for weight management. Semaglutide (Wegovy/Saxenda) and tirzepatide (Zepbound) are specifically approved for obesity treatment in people without diabetes.
Do all GLP-1 drugs cause nausea?
Yes, nausea is the most common side effect across the entire class. It's caused by delayed gastric emptying. Slow titration significantly reduces severity. Dulaglutide tends to cause less nausea than semaglutide.
How GLP-1 agonists work
Natural GLP-1 is released by your gut after eating and has a half-life of only 2 minutes. GLP-1 agonists are modified to resist enzymatic breakdown (DPP-4), extending their action from minutes to days or weeks. They act on receptors in the brain (appetite), pancreas (insulin), gut (motility), and cardiovascular system (protection).
Evolution of the class
- 2005: Exenatide (Byetta) — first GLP-1 drug, twice-daily injection
- 2010: Liraglutide (Victoza) — daily injection, cardiovascular benefit proven
- 2014: Dulaglutide (Trulicity) — weekly injection, easy-to-use pen
- 2017: Semaglutide (Ozempic) — weekly injection, stronger weight loss
- 2022: Tirzepatide (Mounjaro) — dual GIP/GLP-1, even more weight loss
- 2026+: Retatrutide, orforglipron, survodutide — next-generation candidates
Key biomarkers to monitor
Regardless of which GLP-1 drug you're on: HbA1c, fasting glucose/insulin, HOMA-IR, lipid panel (ApoB, triglycerides), liver enzymes, kidney function, vitamin B12, thyroid panel, and body composition (DEXA scan if possible).
Side effects & safety
All GLP-1 agonists share a similar side-effect profile, though severity varies by drug and individual.
| Side Effect | Semaglutide | Tirzepatide | Liraglutide | Dulaglutide |
|---|---|---|---|---|
| Nausea | 40–50% | 25–35% | 30–40% | 20–30% |
| Vomiting | 15–25% | 10–15% | 10–15% | 8–12% |
| Diarrhoea | 15–30% | 15–25% | 10–20% | 10–15% |
| Weight loss | 15–17% | Up to 22.5% | 5–8% | 3–5 kg |
- Pancreatitis — rare but serious across all GLP-1 drugs
- Gallbladder disease — increased risk with any rapid weight loss
- Thyroid C-cell tumours — boxed warning on all GLP-1 drugs (rodent data)
- Muscle loss — 25–40% of weight lost is lean mass without countermeasures
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