If you're trying to figure out which GLP-1 medication will help you lose the most weight, you're not alone — and the answer isn't as simple as picking the one with the biggest number on a label. The clinical trial data is genuinely impressive across the board, but there are meaningful differences between medications that are worth understanding before you talk to your doctor.
Below, we've ranked the major GLP-1 and GLP-1-adjacent medications by average body weight loss, using the best available head-to-head and phase 3 trial data as of mid-2026. Think of this as a knowledgeable friend walking you through the research — not a prescription, but real information you can actually use.
How We Ranked These Medications
All rankings are based on percentage of total body weight lost from baseline in pivotal phase 3 trials at the highest approved or studied dose, in participants without type 2 diabetes (where separate data exists). We're using the most relevant trial for each drug: STEP for semaglutide, SURMOUNT for tirzepatide, and published phase 3 data for others. Where head-to-head trials exist, we note them explicitly.
Important: Average trial results reflect outcomes for a large, diverse population under controlled conditions. Your individual results will depend on your starting weight, metabolic health, diet, activity level, dose tolerance, and how long you stay on the medication. Use these numbers as a reference point, not a guarantee.
The Rankings: GLP-1 Medications by Average Weight Loss
#1 — Tirzepatide (Zepbound / Mounjaro): ~20.2% Body Weight Loss
Tirzepatide sits firmly at the top of the rankings. In the SURMOUNT-1 trial, adults with obesity (without diabetes) lost an average of 20.2% of their body weight over 72 weeks at the highest dose (15 mg weekly). That translates to roughly 48 pounds for someone starting at 240 lbs.
What makes tirzepatide unique is its dual mechanism: it activates both GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) receptors. This combination appears to produce stronger appetite suppression and metabolic effects than GLP-1 alone.
In the landmark SURMOUNT-5 trial published in early 2025, tirzepatide was directly compared to semaglutide 2.4 mg in a head-to-head study. Tirzepatide produced 47% greater relative weight loss than semaglutide — a statistically significant and clinically meaningful difference. This head-to-head data is the strongest evidence we have for ranking tirzepatide above semaglutide.
#2 — Semaglutide 2.4 mg (Wegovy): ~13.7% Body Weight Loss
Semaglutide remains one of the most studied and widely used weight-loss medications in history. In the STEP 1 trial, adults with obesity lost an average of 13.7% of their body weight over 68 weeks using the 2.4 mg weekly injectable dose. For a 240-pound person, that's about 33 pounds.
Semaglutide works by mimicking the GLP-1 hormone, slowing gastric emptying and significantly reducing appetite. It's been approved for chronic weight management since 2021 and has one of the most robust long-term safety profiles of any GLP-1 medication.
It's worth noting that a meaningful percentage of STEP trial participants lost 15%, 20%, or even more — the 13.7% is an average. Some people respond exceptionally well to semaglutide, so if you're already on it and seeing good results, the tirzepatide comparison isn't a reason to switch without a conversation with your provider.
#3 — Oral Semaglutide 50 mg (Rybelsus / Higher-Dose Formulations): ~15% Body Weight Loss
Oral semaglutide has historically been less effective than the injectable version due to absorption limitations, but higher-dose oral formulations (25 mg and 50 mg) studied in the OASIS and PIONEER PLUS trials have shown weight loss approaching or slightly exceeding injectable semaglutide 1 mg doses. The 50 mg oral dose in OASIS 1 showed approximately 15.1% weight loss at 68 weeks — genuinely competitive, though slightly less than injectable semaglutide 2.4 mg in direct-comparison context.
For people who prefer not to self-inject, oral semaglutide at higher doses is becoming a more viable option, though availability and insurance coverage vary.
#4 — Liraglutide 3.0 mg (Saxenda): ~5–8% Body Weight Loss
Liraglutide was the first GLP-1 receptor agonist approved specifically for weight management (2014). It requires daily injections and produces more modest results — typically 5 to 8% body weight loss in clinical trials. It remains a legitimate option, particularly when cost or insurance access is a barrier to newer medications, but it is generally less effective than semaglutide or tirzepatide at comparable durations.
#5 — Dulaglutide (Trulicity) and Exenatide (Byetta/Bydureon): ~2–4% Body Weight Loss
These older GLP-1 medications were primarily developed for blood sugar control in type 2 diabetes, and their weight loss effects are modest — typically in the 2 to 4% range. They are not approved for weight management as a primary indication and are rarely prescribed with weight loss as the primary goal in 2026.
Side-by-Side Summary
- Tirzepatide (Zepbound): ~20.2% avg loss | Dual GLP-1/GIP agonist | Weekly injection
- Semaglutide 2.4 mg (Wegovy): ~13.7% avg loss | GLP-1 agonist | Weekly injection
- Oral Semaglutide 50 mg: ~15.1% avg loss | GLP-1 agonist | Daily pill
- Liraglutide 3.0 mg (Saxenda): ~5–8% avg loss | GLP-1 agonist | Daily injection
- Dulaglutide / Exenatide: ~2–4% avg loss | GLP-1 agonist | Weekly/daily injection
Does "Best for Weight Loss" Mean "Best for You"?
Not necessarily. The highest average weight loss doesn't automatically make a medication the right choice for every person. Here are a few things to weigh alongside efficacy data:
- Tolerability: Tirzepatide and semaglutide have similar side effect profiles (nausea, vomiting, constipation are most common), but individuals respond differently. Some people tolerate one much better than the other.
- Insurance and cost: Coverage for Zepbound vs. Wegovy varies dramatically by insurer and employer plan. Out-of-pocket costs without insurance can exceed $1,000/month for either.
- Comorbidities: If you have type 2 diabetes, your doctor may factor in glycemic control benefits, which differ between medications. Semaglutide also has established cardiovascular outcome data (SELECT trial, 2023) showing a 20% reduction in major cardiovascular events.
- Availability: Compounded semaglutide and tirzepatide have been widely available during shortage periods, though FDA policy around compounding continues to evolve.
Remember: These medications work best as part of a broader lifestyle approach. Trial participants also followed reduced-calorie diets and increased physical activity. The drug amplifies your efforts — it doesn't replace them.
How to Estimate Your Personal Weight Loss
Averages are useful context, but what you probably really want to know is: how much could I lose? That depends on your current weight, your target, your medication and dose, and your timeline. Rather than doing rough math in your head, you can use our free calculator to model projected weight loss based on your specific inputs.
Try the GLP-1 Weight Loss Calculator at GLP1Calc →
It takes about 60 seconds and gives you a personalized estimate based on the same clinical trial data discussed in this article — without requiring any sign-up or personal health information.
The Bottom Line
When GLP-1 medications are ranked purely by average weight loss in clinical trials, tirzepatide leads the field at roughly 20% body weight loss, followed by semaglutide at approximately 13.7%. The 2025 SURMOUNT-5 head-to-head trial confirmed tirzepatide's advantage with a 47% greater relative weight loss compared to semaglutide. Older GLP-1 medications like liraglutide are effective but produce more modest results.
The best medication for you, though, is the one you can access, tolerate, afford, and stay on long enough to see meaningful results. Use this data to have a more informed conversation with your doctor — and use our calculator to translate population averages into a personalized estimate for your own journey.