Tirzepatide
The Mounjaro molecule
Dual GLP-1/GIP Receptor Agonist
Evidence Level: Strong Evidence
Multiple large human trials, FDA approval, established safety profile
Regulatory Status: FDA-approved for diabetes (Mounjaro) and weight loss (Zepbound)
Tirzepatide is the 'second generation' of GLP-1 medications. While semaglutide targets one hormone receptor (GLP-1), tirzepatide hits two: GLP-1 and GIP. This dual action appears to produce even better results for weight loss and blood sugar control. It's the strongest medical weight loss option currently available.
How It Works
GLP-1 effects (same as semaglutide):
• Reduces appetite and cravings
• Slows stomach emptying
• Improves insulin response
GIP effects (the new part):
• Enhances the GLP-1 effects on appetite
• Improves fat tissue metabolism
• May help preserve muscle during weight loss
The combination appears to be synergistic—the whole is greater than the sum of its parts.
Potential Benefits
- Superior weight loss: 20-25% average in trials (vs 15% for semaglutide)
- Some users report fewer GI side effects than semaglutide
- Better blood sugar control than single-receptor drugs
- Weekly injection like semaglutide
- May preserve more muscle mass during weight loss
- Strong clinical trial data supporting safety and efficacy
Risks & Considerations
- GI side effects still common (nausea, diarrhea, constipation)
- Newer to market = less long-term safety data
- Same thyroid cancer warning as semaglutide
- Very expensive ($1,000+/month without insurance)
- Frequent shortages and supply issues
- May cause injection site reactions
- Risk of pancreatitis (rare but serious)
Dosing Information
Like semaglutide, tirzepatide requires slow titration. Starting dose is 2.5mg weekly.
- •Starting dose: 2.5mg/week for 4 weeks
- •Escalation: 2.5 → 5 → 7.5 → 10 → 12.5 → 15mg
- •Each increase = 4 weeks minimum
- •Maximum dose: 15mg/week
- •Many people see good results at 10mg without needing max dose
Practical Tips
- 1Same injection routine as semaglutide (weekly, rotate sites)
- 2If switching from semaglutide: start at 2.5mg regardless of previous dose
- 3The pen delivers fixed doses—no mixing or measuring
- 4Keep refrigerated; room temp OK for up to 21 days after first use
- 5Protein and resistance training are even more important here
Key Research
SURMOUNT-1 Trial
New England Journal of Medicine, 2022
Average weight loss of 20.9% with 15mg dose vs 3.1% with placebo. About 1 in 3 participants lost more than 25% of body weight.
SURMOUNT-4 Trial
JAMA, 2023
Continuing tirzepatide for 1 year maintained 18.4% weight loss vs regaining weight with placebo.
Related Goals
Related Treatments
Disclaimer: This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider before starting any treatment. Evidence levels and regulatory status can change—this content was last updated November 2024.