Best GLP-1 for Weight Loss: Comparing All Options

With multiple GLP-1 receptor agonists now available, a common question is: which one works best for weight loss? The answer depends on several factors, but clinical trial data gives us a clear picture.

Head-to-Head: Weight Loss by Medication

Here is a summary of the major clinical trials measuring weight loss in people without diabetes:

Sources: Jastreboff et al., 2022 (NEJM), Wilding et al., 2021 (NEJM), Pi-Sunyer et al., 2015 (NEJM).

Tirzepatide (Mounjaro / Zepbound)

Tirzepatide is technically a dual GIP/GLP-1 receptor agonist, meaning it activates two incretin receptors rather than one. In the SURMOUNT-1 trial, participants on the highest dose (15mg) lost an average of 22.5% of body weight - the most of any medication studied to date.

The FDA approved tirzepatide for weight management under the brand name Zepbound in November 2023.

Pros:

• Highest average weight loss in clinical trials
• Weekly injection
• Also approved for type 2 diabetes (as Mounjaro)

Cons:

• Higher rate of gastrointestinal side effects at top doses
• Supply shortages have been common
• Cost can be significant without insurance

Semaglutide (Wegovy / Ozempic)

Semaglutide was the first GLP-1 to demonstrate truly dramatic weight loss results. The STEP programme (a series of four Phase 3 trials) showed consistent results:

• STEP 1: 14.9% weight loss (non-diabetic adults)
• STEP 2: 9.6% (adults with diabetes)
• STEP 3: 16.0% (with intensive behavioral therapy)
• STEP 4: Regain of two-thirds of lost weight after discontinuation

Wegovy (2.4mg semaglutide) is FDA-approved specifically for chronic weight management. Ozempic (up to 2.0mg) is approved for type 2 diabetes but is widely used off-label for weight loss.

Pros:

• Extensive safety data (largest cardiovascular outcomes trial - SELECT)
• Weekly injection
• Oral version available for diabetes (Rybelsus)

Cons:

• Slightly less weight loss than tirzepatide on average
• Nausea common during dose escalation
• Ongoing supply constraints

Liraglutide (Saxenda)

Liraglutide was the first GLP-1 approved for weight management (2014). While its results are more modest than newer options, it remains a proven treatment.

Pros:

• Longest track record for weight loss
• Daily dosing allows more flexible adjustment
• Well-studied safety profile

Cons:

• Requires daily injection (vs weekly for others)
• Lower average weight loss than semaglutide or tirzepatide
• Twice-daily injections with the older formulation (Victoza)

Which GLP-1 Should You Choose?

The best choice depends on individual factors:

• Maximum weight loss: Tirzepatide (Zepbound) leads on efficacy data
• Cardiovascular benefit: Semaglutide (Wegovy) has the strongest CV evidence from the SELECT trial
• Insurance coverage: Many plans cover Mounjaro or Wegovy but not both - check your formulary
• Needle anxiety: An oral semaglutide option exists for diabetes, with higher-dose weight-loss pills in late-stage trials
• Budget concerns: See our guide on GLP-1 costs and savings

What About Combining GLP-1 With Other Approaches?

GLP-1 medications work best as part of a comprehensive approach:

1. Diet - Focus on protein-rich meals to preserve lean mass during weight loss
2. Exercise - Resistance training is particularly important to maintain muscle
3. Behavioral support - The STEP 3 trial showed that adding behavioral therapy boosted results to 16% weight loss
4. Tracking - Monitoring your medication and progress helps maintain consistency. GLP Pal makes this easy

What Is Coming Next?

The pipeline includes even more powerful options:

• Retatrutide - a triple agonist (GLP-1/GIP/glucagon) showing up to 24% weight loss in Phase 2
• Orforglipron - an oral GLP-1 in Phase 3 trials
• Survodutide - a dual GLP-1/glucagon agonist

For the full list, see our complete guide to GLP-1 medications.

The Bottom Line

Based on current evidence, tirzepatide produces the most weight loss and semaglutide has the broadest evidence base including cardiovascular benefits. Both are excellent options. Work with your doctor to determine which medication, dose, and approach are right for your specific situation.