The New Era of Weight Loss: Why the World Is Obsessed with Mounjaro
Imagine losing 22% of your body weight in less than two years — without invasive surgeries, without extreme diets impossible to maintain. For a 220-pound person, that means eliminating nearly 50 pounds consistently and sustainably. Sounds like science fiction? It's not. It's the reality millions of people worldwide are experiencing with tirzepatide, marketed as Mounjaro (for diabetes) and Zepbound (for obesity).
But why has this medication become a global phenomenon? Why are Hollywood celebrities publicly admitting to using it? And more importantly: why are some governments making access difficult to a treatment that can save lives?
In this investigative article, we go beyond sensationalist headlines. We'll understand the science, the numbers, the controversies, and reveal truths the pharmaceutical industry prefers to keep in the background.
What Is Tirzepatide and How Does It Work?
The Science Behind the "Miracle"
Tirzepatide is not magic — it's cutting-edge science. Developed by American pharmaceutical giant Eli Lilly, it represents a significant evolution over previous medications like Ozempic (semaglutide).
While Ozempic acts on only one hormonal receptor (GLP-1), tirzepatide is the first medication in history to simultaneously act on two receptors:
GLP-1 (Glucagon-Like Peptide-1): A hormone that increases insulin production, reduces appetite, and slows gastric emptying.
GIP (Glucose-dependent Insulinotropic Polypeptide): A hormone that enhances GLP-1 effects and has direct action on fat metabolism.
What Happens in Your Body?
When you apply the weekly tirzepatide injection, a cascade of metabolic events is triggered:
- In the brain: Satiety centers are activated, making you feel satisfied with smaller portions
- In the stomach: Gastric emptying is slowed, prolonging the feeling of fullness
- In the pancreas: Insulin production is stimulated intelligently (only when glucose is elevated)
- In the liver: Glucagon production is suppressed, reducing sugar release into the bloodstream
Clinical Results: The Impressive Numbers
SURMOUNT and SURPASS Studies
The clinical trials for tirzepatide are, without exaggeration, the most impressive ever recorded for a weight loss medication. Data from SURMOUNT studies published in the New England Journal of Medicine:
| Metric | Tirzepatide 15mg | Placebo |
|---|---|---|
| Average weight loss | 22.5% | 2.4% |
| Patients who lost ≥5% | 89% | 28% |
| Patients who lost ≥10% | 78% | 10% |
| Patients who lost ≥20% | 63% | 1.3% |
63% of patients lost more than 20% of their body weight. This means a 265-pound person could reach 212 pounds — a transformation previously only possible with bariatric surgery.
Direct Comparison: Mounjaro vs Ozempic
A randomized study with 1,897 patients directly compared tirzepatide and semaglutide (Ozempic). Results after 40 weeks:
- Tirzepatide: 21.4% weight loss
- Semaglutide: 11.2% weight loss
Tirzepatide proved to be nearly twice as effective as its main competitor.
Timeline: The History of Tirzepatide
- 2016: Eli Lilly begins first clinical studies
- 2019: Phase 3 trials begin (SURPASS and SURMOUNT)
- May 2022: FDA approves Mounjaro for type 2 diabetes
- September 2022: European Union approves tirzepatide
- November 2022: Canada approves the medication
- December 2022: Australia grants approval
- November 2023: FDA approves Zepbound specifically for obesity
- September 2023: ANVISA approves Mounjaro in Brazil for diabetes
- May 2025: Mounjaro arrives at Brazilian pharmacies
- December 2024: FDA approves Zepbound for obstructive sleep apnea
Countries That Approved and Their Prices
The Brutal Price Difference
| Country | Monthly Price (USD) | Note |
|---|---|---|
| 🇺🇸 USA | $1,000 - $1,300 | Without insurance |
| 🇺🇸 USA | $25 | With savings card |
| 🇬🇧 UK | $150 - $400 | NHS doesn't cover for obesity |
| 🇧🇷 Brazil | $500 - $700 | Initial estimate |
| 🇲🇽 Mexico | $400 - $600 | More accessible |
The price difference between countries is abysmal. In the USA, without insurance, you pay over $1,000 per month.
The Controversy: Why Do Governments Block Access?
The Case of Brazil
ANVISA approved Mounjaro in September 2023, but only for type 2 diabetes — not for obesity. This means doctors can prescribe "off-label," but:
- Health plans are not required to cover it
- The pharmacy price is prohibitive
- Importing cheaper versions is restricted
Following the Money
Eli Lilly reported revenues of $13.8 billion in Q4 2025 alone, driven mainly by Mounjaro and Zepbound. The company has direct interest in:
- Maintaining high prices in developed markets
- Fighting generic and compounded versions
- Pressuring governments for patent protection
Patents for tirzepatide are protected until 2036 in the USA, with some extensions until 2039.
The End of Compounding Pharmacies
The FDA Decision
In December 2024, the FDA declared that the tirzepatide shortage had ended. This had a devastating consequence for millions of Americans: compounding pharmacies were prohibited from producing tirzepatide.
Result? Patients who paid $200-400/month for compounded versions now need to pay $1,000+ for the brand version.
Eli Lilly Sued
The pharmaceutical giant also sued online pharmacies selling unauthorized versions. Between February 2024 and May 2025, more than 18,300 illegal weight loss products were seized at borders.
Side Effects: What You Need to Know
Common Effects (usually temporary)
- Nausea: 12-18% of patients
- Diarrhea: 12-17%
- Constipation: 6-8%
- Vomiting: ~5%
- Abdominal pain: 5-7%
Serious Effects (rare but important)
- Pancreatitis: Rare cases reported
- Gallbladder problems: Increased risk
- Diabetic retinopathy: In patients with pre-existing diabetes
The Susan McGowan Case
In January 2026, the first death in the UK officially linked to tirzepatide was confirmed. Susan McGowan suffered multiple organ failure, septic shock, and pancreatitis after two low-dose injections.
Good News: Mental Health
A study published in January 2026 in the Obesity Journal brought relief: tirzepatide is not associated with increased depression or suicidal ideation. Patients actually showed improvement in depression scores (PHQ-9) compared to placebo.
Mounjaro vs Zepbound: What's the Difference?
| Feature | Mounjaro | Zepbound |
|---|---|---|
| Active ingredient | Tirzepatide | Tirzepatide |
| Manufacturer | Eli Lilly | Eli Lilly |
| FDA Approval | May 2022 | November 2023 |
| Indication | Type 2 diabetes | Obesity/Overweight |
| Doses | 2.5mg to 15mg | 2.5mg to 15mg |
They are exactly the same medication, just with different indications. Eli Lilly created two brands to maximize insurance coverage and marketing.
How Treatment Works in Practice
Dosing Protocol
Treatment follows a gradual escalation to minimize side effects:
- Weeks 1-4: 2.5mg/week (starting dose)
- Weeks 5-8: 5mg/week
- Weeks 9-12: 7.5mg/week
- Weeks 13-16: 10mg/week
- Weeks 17+: 12.5mg or 15mg/week (maximum dose)
The Maintenance Problem
Here's the inconvenient truth: if you stop using it, the weight tends to return. Studies show that GLP-1 and GIP hormones return to previous levels, and with them, hunger and old eating patterns.
This means that for many, tirzepatide may be a lifelong treatment — with costs that can exceed $100,000 over a decade.
Alternatives and Future
Oral Tirzepatide: In Development
Eli Lilly is developing an oral version of tirzepatide, eliminating the need for injections. Phase 3 studies are underway, with results expected for 2026-2027.
New Competitors
- Retatrutide (Eli Lilly): Triple agonist (GLP-1, GIP, and glucagon) — even more potent
- Orforglipron (Eli Lilly): Oral GLP-1 version
- CagriSema (Novo Nordisk): Combination of semaglutide with cagrilintide
When Will We Have Generics?
Main tirzepatide patents expire in 2036. Accessible generic versions should only reach the market in the 2040s.
Frequently Asked Questions
Is Mounjaro safe for long-term use?
Studies of up to 72 weeks show an acceptable safety profile. Long-term studies (5+ years) are still ongoing. Medical monitoring is essential.
Can I buy Mounjaro without a prescription?
No. It's a prescription-only medication in all countries where it's approved. Buying without a prescription is illegal and dangerous.
Does Mounjaro work for everyone?
About 89% of patients lose at least 5% of their weight. However, 11% don't respond adequately. Genetic, metabolic, and behavioral factors influence results.
What's the difference between Mounjaro and Ozempic?
Mounjaro (tirzepatide) acts on two receptors (GLP-1 and GIP), while Ozempic (semaglutide) acts on only one (GLP-1). Mounjaro demonstrates ~50% greater weight loss in comparative studies.
Conclusion: Revolution or Trap?
Tirzepatide represents, without doubt, an extraordinary scientific advance. For the first time, we have a medication that rivals bariatric surgery in terms of efficacy, without surgical risks.
But the story has dark sides:
- Prohibitive prices exclude most of the world's population
- Patents until 2036+ guarantee monopoly for another decade
- Governments frequently protect corporate interests over public health
- Potential dependence on lifelong treatment
- Access inequality between rich and poor countries
The final question is not whether tirzepatide works — the data is unequivocal. The question is: who will have access to it?
The weight loss revolution has arrived. But, like so many other revolutions in the history of medicine, it came with a price — literally.
Sources and References
- FDA - Mounjaro Approval
- FDA - Zepbound Approval
- NEJM - SURMOUNT-1 Study
- Eli Lilly - Official Information
Last updated: February 6, 2026
This article is for informational purposes and does not replace professional medical advice. Always consult a doctor before starting any treatment.
