Tirzepatide produces the largest average weight loss, semaglutide has the deepest safety and cardiovascular evidence base, and the "best" choice depends on your specific health profile.
Both are available through Luma Health as compounded medications: semaglutide at $197/month and tirzepatide at $297/month, flat, with a real physician evaluation to help determine the right fit.
"What's the best GLP-1 for weight loss" doesn't have one universal answer, because the medications differ meaningfully in mechanism, average efficacy, side-effect profile, and the depth of evidence behind them. Below, we walk through how the major options actually compare, and which patient profiles tend to do better with each.
How the Major GLP-1 Options Compare
| Semaglutide | Tirzepatide | |
|---|---|---|
| Mechanism | GLP-1 receptor agonist | Dual GIP + GLP-1 receptor agonist |
| Avg. weight loss (trial) | ~14.9% at 68 weeks (STEP 1) | ~20-22.5% at 72 weeks (SURMOUNT-1) Higher |
| Dosing frequency | Weekly | Weekly |
| Cardiovascular outcomes data | Strong — SELECT trial Established | Developing |
| Years on market (class) | Since 2017 (semaglutide) / 2005 (class) | Since 2022 |
| Common side effects | Nausea, GI upset (moderate) | Nausea, GI upset (moderate, sometimes higher at max dose) |
| Luma Health price | $197/month, flat | $297/month, flat |
Weight loss percentages above reflect clinical trial averages, not individual guarantees — actual results vary based on starting weight, dose, adherence, and individual biology.
Where Liraglutide Fits In
Semaglutide and tirzepatide get most of the attention, but liraglutide (brand name Saxenda) was the original GLP-1 medication approved specifically for chronic weight management, and it still has a role for certain patients. Its average weight loss in trials is meaningfully lower — typically in the 5-8% range — but its daily dosing schedule allows for more granular titration, and its shorter half-life means side effects tend to resolve faster if a dose adjustment is needed. Some providers use liraglutide as a gentler starting point for patients who've had difficulty tolerating other GLP-1 medications, before considering a transition to a weekly injectable if greater efficacy is needed.
How to Actually Evaluate "Best"
Weight loss percentage alone is an incomplete way to judge these medications. A drug that produces excellent average weight loss but causes side effects severe enough that many patients discontinue isn't necessarily the better real-world choice. Tolerability, the pace of dose titration, cardiovascular safety data, and practical accessibility (cost, insurance coverage, ease of getting a prescription) all factor into which medication actually works best for a given person, not just which one wins on a single efficacy chart.
It's also worth remembering that clinical trial populations are curated and closely monitored — real-world results, including compliance with dosing schedules and follow-up visits, tend to run somewhat below trial averages. That's not a reason to distrust the data; it's a reason to set realistic expectations and to lean on ongoing provider support rather than treating a headline percentage as a promise.
Why the Mechanism Difference Matters
Semaglutide works by activating GLP-1 receptors, which slows gastric emptying, increases satiety, and improves insulin sensitivity. Tirzepatide activates both GLP-1 and GIP receptors, and that dual mechanism appears to produce somewhat greater average weight loss and larger A1C reductions in head-to-head trial data. That doesn't automatically make tirzepatide the "better" choice for every patient, though — it just means the two work through overlapping but distinct pathways, and individual response can vary regardless of trial averages.
Evidence Depth Is a Real Consideration
Semaglutide has a considerably longer track record. The broader GLP-1 receptor agonist class has been FDA-approved since 2005, and semaglutide specifically since 2017, giving clinicians years of real-world safety data on top of trial data. The SELECT cardiovascular outcomes trial, which followed 17,604 patients with pre-existing cardiovascular disease, specifically demonstrated that semaglutide reduced major adverse cardiovascular events — a meaningful data point for patients with heart disease risk factors. Tirzepatide's cardiovascular outcomes data is still developing, which matters more for some patients than others depending on their individual risk profile.
How Titration Schedules Compare
Both semaglutide and tirzepatide follow a gradual dose-escalation schedule designed to minimize gastrointestinal side effects, typically starting at a low introductory dose and increasing every four weeks until reaching a therapeutic maintenance level. Semaglutide's schedule generally spans about 16-20 weeks to reach the highest studied maintenance dose; tirzepatide's follows a similar four-week-per-step cadence toward its own maintenance range. Neither schedule is meaningfully faster or slower in a way that should drive your choice between the two — the titration pace is more about safety and tolerability than about getting to results quickly, and rushing it rarely produces meaningfully better or faster outcomes for most patients.
What does vary is how a provider handles titration in practice. Some providers follow a rigid, one-size-fits-all schedule regardless of how a patient is tolerating each step; better practice is adjusting the pace based on individual side-effect response — slowing down for a patient experiencing significant nausea, or maintaining a slightly faster pace for a patient tolerating each increase well. This individualized approach is one of the more meaningful differences between providers, even when the underlying medication is identical. When comparing options, it's worth asking directly whether a provider adjusts titration pace based on your reported side effects, or whether everyone follows the same fixed schedule regardless of how treatment is going for them individually.
Matching the Medication to the Patient
- Have established cardiovascular disease or significant risk factors
- Want the medication with the longest real-world safety track record
- Have more moderate weight loss goals
- Prioritize cost (starts lower per month)
- Have significant weight to lose and want the highest average efficacy
- Have type 2 diabetes and want maximum A1C improvement
- Haven't responded as well as expected to semaglutide
- Are comfortable with a slightly higher monthly cost
The right choice depends on your BMI, health history, cardiovascular risk factors, and personal response — which is exactly why Luma Health starts every patient with a real medical evaluation from a licensed provider, rather than defaulting everyone to the same medication.
Comparing Tolerability Across Options
Efficacy numbers get most of the attention, but tolerability is often the practical factor that determines whether someone stays on treatment long enough to see results. Across trial data, gastrointestinal side effects (nausea, constipation, diarrhea) are the most commonly reported issue for both semaglutide and tirzepatide, typically most pronounced during the first several weeks of dose titration. Discontinuation rates due to side effects in the major trials were modest — in the single digits as a percentage of participants — but real-world discontinuation, outside the closely monitored trial setting, tends to run somewhat higher, often tied to patients increasing their dose faster than recommended or not having easy access to a provider when side effects arise.
Liraglutide, the older daily-injection option, is sometimes better tolerated by patients who've struggled with weekly medications specifically because the daily dosing allows smaller, more gradual titration steps. This isn't a universal rule — individual response varies considerably — but it's a reasonable option to discuss if you've had a difficult time with the GI side effects of a weekly medication.
What Trial Averages Don't Capture
It's worth being direct about a limitation of headline trial statistics: they describe the average patient in a closely monitored research setting, following a specific dosing protocol, often with more frequent check-ins than a typical patient receives in routine care. Real-world results tend to track somewhat below trial averages for this reason — not because the medication is less effective outside a trial, but because adherence, dose consistency, and lifestyle factors vary more in everyday life than in a structured research protocol.
This isn't a reason to discount the trial data; it's a reason to treat the published percentages as a reasonable expectation range rather than a guaranteed outcome, and to lean on consistent provider check-ins to keep your own results tracking closer to what the research suggests is achievable.
Cost and Access Considerations
Brand-name list prices for both medications typically run well over $1,000 per month without insurance, though manufacturer savings programs and expanding insurance coverage have brought costs down for many patients — roughly 49% of large employers now cover GLP-1s for weight management, up from 44% the year before. For patients without coverage, compounded versions prepared by licensed 503A pharmacies remain considerably more affordable, while containing the same active pharmaceutical ingredient as the brand-name product.
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Tirzepatide produces the highest average weight loss in clinical trials, at roughly 20-22.5% of body weight at 72 weeks in SURMOUNT-1, compared to roughly 14.9% for semaglutide at 68 weeks in STEP 1. These are trial averages, not individual guarantees.
Not necessarily. Tirzepatide shows greater average weight loss, but semaglutide has a longer real-world safety track record and stronger established cardiovascular outcomes data via the SELECT trial. The better choice depends on individual health history and goals.
Semaglutide activates GLP-1 receptors alone. Tirzepatide activates both GLP-1 and GIP receptors, a dual mechanism that appears to produce somewhat greater average weight loss and A1C improvement in head-to-head data.
Coverage varies by plan but has been expanding — roughly 49% of large employers now cover GLP-1s for weight management. For patients without coverage, compounded options through a licensed provider are typically far less expensive than brand-name list price.
This is a common and reasonable conversation to have with your prescribing provider if you haven't seen the response you expected after an adequate trial period at an appropriate dose. Switching should always be guided by your provider rather than done independently.
Neither by default. Every Luma Health patient starts with a real medical evaluation from a licensed provider who considers your BMI, health history, and goals before recommending compounded semaglutide ($197/month) or tirzepatide ($297/month).
Trial averages come from a closely monitored research setting with structured dosing protocols, so real-world results often track somewhat below the published percentages. Treat trial data as a reasonable expectation range, not a guarantee, and use consistent provider check-ins to help your results track closer to what the research suggests.
For some patients, yes, since its daily dosing allows smaller, more gradual titration steps. This isn't universal, but it's worth discussing with your provider if you've had a difficult time with GI side effects from a weekly medication.
References
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989-1002. PubMed 33567185
- Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022;387(3):205-216. PubMed 35658024
- Lincoff AM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT). N Engl J Med. 2023;389(24):2221-2232. PubMed 37952131
- Garvey WT, et al. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2). Lancet. 2023;402(10402):613-626. PubMed 37385275
- Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564. PubMed 35441470
- Mercer. National Survey of Employer-Sponsored Health Plans, 2025: GLP-1 coverage findings. Mercer.com. 2025. Mercer.com
- U.S. Food and Drug Administration. Prescribing Information for Wegovy (semaglutide). FDA.gov. 2025. FDA.gov
- U.S. Food and Drug Administration. Prescribing Information for Zepbound (tirzepatide). FDA.gov. 2025. FDA.gov