Pillar Guide

Peptides for Weight Loss

Understanding GLP-1 peptides like Semaglutide and Tirzepatide - how they work, their effectiveness, and what the research shows for weight management.

Semaglutide Tirzepatide

How GLP-1 Peptides Cause Weight Loss

GLP-1 (Glucagon-Like Peptide-1) receptor agonists are a class of peptides that mimic a natural hormone your body produces after eating.

Key Mechanisms:

1
Appetite Suppression

Signals the brain to feel full, reducing hunger and food cravings

2
Slowed Gastric Emptying

Food stays in stomach longer, prolonging satiety

3
Insulin Regulation

Improves blood sugar control, reducing fat storage

4
Reduced Food Reward

Lessens the pleasure response to high-calorie foods

Clinical Results: GLP-1 medications are among the most effective pharmaceutical weight loss treatments ever developed, with average weight loss of 15-22% of body weight in clinical trials.

Semaglutide (Ozempic / Wegovy)

FDA Approved Most Popular

Semaglutide is a GLP-1 receptor agonist approved for type 2 diabetes (Ozempic) and chronic weight management (Wegovy). It has become one of the most prescribed weight loss medications.

Clinical Trial Results
  • Average 15-17% body weight loss
  • 33% of patients lost 20%+ weight
  • Significant reduction in waist circumference
  • Improved cardiovascular markers
  • Reduced HbA1c in diabetics
Common Side Effects
  • Nausea (especially early use)
  • Diarrhea or constipation
  • Vomiting
  • Abdominal pain
  • Fatigue
Dosing Protocol:
Weeks Dose Purpose
1-40.25mg weeklyInitiation
5-80.5mg weeklyTitration
9-121.0mg weeklyTitration
13-161.7mg weeklyTitration
17+2.4mg weeklyMaintenance

Tirzepatide (Mounjaro / Zepbound)

FDA Approved Dual Agonist

Tirzepatide is a dual GIP/GLP-1 receptor agonist, meaning it activates two incretin pathways simultaneously. This dual mechanism appears to produce superior weight loss results.

Clinical Trial Results
  • Average 20-22% body weight loss
  • 36% of patients lost 25%+ weight
  • Superior to semaglutide in head-to-head
  • Significant HbA1c reduction
  • Improved lipid profiles
Common Side Effects
  • Nausea (dose-dependent)
  • Diarrhea
  • Decreased appetite
  • Vomiting
  • Constipation
Dosing Protocol:
Weeks Dose
1-42.5mg weekly
5-85mg weekly
9-127.5mg weekly
13-1610mg weekly
17+12.5-15mg weekly (max)

Semaglutide vs Tirzepatide Comparison

Factor Semaglutide Tirzepatide
Mechanism GLP-1 only GLP-1 + GIP (dual)
Average Weight Loss 15-17% 20-22%
Max Dose 2.4mg weekly 15mg weekly
Brand Names Ozempic, Wegovy, Rybelsus Mounjaro, Zepbound
FDA Weight Loss Approval Yes (Wegovy) Yes (Zepbound)
Oral Option Yes (Rybelsus) In development

Other Weight Loss Peptides

Liraglutide (Saxenda)

FDA Approved

Earlier GLP-1 agonist, daily injection. Average 8% weight loss. More side effects than newer options but well-established safety profile.

AOD-9604

Research

Fragment of human growth hormone (HGH). Researched for fat metabolism without GH's muscle-building effects. Limited human data.

MOTS-c

Research

Mitochondrial-derived peptide that regulates metabolism. Early research shows effects on insulin sensitivity and fat oxidation.

Tesamorelin

FDA Approved

GHRH analog approved for HIV-associated lipodystrophy. Reduces visceral fat. Not approved for general weight loss.

Frequently Asked Questions

Studies show that most patients regain weight after stopping GLP-1 medications if lifestyle changes aren't maintained. The STEP 4 trial showed 2/3 of lost weight was regained within a year of stopping semaglutide. These medications work best as part of a long-term weight management strategy including diet and exercise.

Head-to-head trials (SURMOUNT-5) showed tirzepatide produced greater weight loss than semaglutide (20.2% vs 13.7%). However, individual responses vary. Tirzepatide may be better for those needing maximum weight loss, while semaglutide has longer real-world safety data. Both require prescription and medical supervision.

Studies show approximately 25-40% of weight lost on GLP-1 medications is lean mass (muscle). This is similar to other rapid weight loss methods. To minimize muscle loss: maintain adequate protein intake (1.2-1.6g/kg), engage in resistance training, and ensure gradual weight loss through proper dose titration.

Compounded semaglutide and tirzepatide from licensed 503B pharmacies can be legal alternatives during brand shortages. However, quality varies significantly. The FDA has warned about products containing semaglutide salt forms (not bioequivalent) and contaminated products. Only use compounded versions from verified, licensed pharmacies with proper testing documentation.
Dosing Calculator

Calculate your semaglutide or tirzepatide dosing

Semaglutide Calculator Tirzepatide Calculator
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Important Note

GLP-1 medications require a prescription and medical supervision. They are not appropriate for everyone. Consult with a healthcare provider to determine if these medications are right for you.

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Disclaimer: This content is for educational purposes only and is not medical advice. GLP-1 medications are prescription drugs with potential serious side effects. Always consult a qualified healthcare provider before starting any weight loss medication.