Semaglutide vs Tirzepatide vs Retatrutide (2026): Head-to-Head Clinical Data, Dosing & Access

I have spent the last two years building research infrastructure for this exact question. Here is what went into this page specifically:

• I pulled the full text of the SURMOUNT-5 head-to-head trial published in the New England Journal of Medicine on May 11, 2025 (DOI: 10.1056/NEJMoa2416394) and cross-referenced it with the Phase 3 TRIUMPH-4 topline readout from Eli Lilly on December 11, 2025.
• I compared the Phase 3 retatrutide data to the earlier Jastreboff Phase 2 publication to verify the new 28.7% figure is consistent with the 24.2% Phase 2 result, not an outlier.
• I verified every reconstitution table on this page with the free reconstitution calculator I built, using the same BAC water volumes and vial sizes most research-market suppliers ship.
• I reviewed the current PepPal supplier profiles for Peptide Partners and Orbitrex Peptides to pull live research-market pricing ranges for all three compounds. Both are Finnrick Analytics-tested. I am not guessing at prices — these come from my own supplier review process.
• I cross-checked the retatrutide dysesthesia signal (20.9% incidence at 12 mg in TRIUMPH-4) against the earlier Phase 2 adverse-event table, where it was not reported. That safety signal is new, and I flag it explicitly in the side-effect section.
• Every claim on this page is anchored to a Tier 1 (peer-reviewed clinical trial), Tier 2 (systematic review), or Tier 3 (manufacturer regulatory filing) source. I do not use supplier marketing copy as a source. See my full source hierarchy.

The protocols for each compound live on my companion site, PeptideDosingProtocols.com. If you want the full 14-section dosing, titration, and reconstitution breakdown for any single compound, use the individual protocol links throughout this page.

The easiest way to understand this comparison is as three generations of the same scientific idea: harnessing gut-hormone signaling to control appetite, blood sugar, and metabolism. Each generation adds one more receptor target.

Generation 1 — Semaglutide (2017 / 2021). A single-receptor GLP-1 agonist. It proved that a long-acting GLP-1 could produce clinically meaningful weight loss. The STEP 1 trial published in the New England Journal of Medicine in 2021 showed 14.9% mean weight loss at 68 weeks. FDA-approved for type 2 diabetes as Ozempic (2017) and for chronic weight management as Wegovy (2021). Manufactured by Novo Nordisk.

Generation 2 — Tirzepatide (2022 / 2023). A dual GIP/GLP-1 agonist. Adding GIP receptor activation on top of GLP-1 pushed weight loss into a new tier. SURMOUNT-1 (NEJM 2022) showed 22.5% mean weight loss at 72 weeks on the 15 mg dose. FDA-approved for type 2 diabetes as Mounjaro (2022) and for chronic weight management as Zepbound (2023). Manufactured by Eli Lilly.

Generation 3 — Retatrutide (investigational). A triple agonist targeting GLP-1, GIP, and glucagon receptors. The glucagon component is what makes it different — glucagon receptor activation increases hepatic energy expenditure and fatty-acid oxidation in the liver. Phase 2 data in 2023 showed 24.2% weight loss at 48 weeks. The first Phase 3 readout (TRIUMPH-4, December 2025) reported 28.7% mean weight loss at 68 weeks. Not yet FDA-approved. Seven additional Phase 3 readouts are expected during 2026. Manufactured by Eli Lilly.

Reading across that sequence — one receptor, two, three — the efficacy ladder is real and measurable. But so is the cost: each generation adds more gastrointestinal side effects, and retatrutide introduced a new signal (dysesthesia) that did not appear in Phase 2. More on that in the side-effect section.

All three compounds are once-weekly subcutaneous injections. All three use fatty-acid conjugation to bind albumin and extend half-life. The structural differences matter biochemically but the administration experience is nearly identical: a small-volume shot in the abdomen, thigh, or upper arm, once a week.

What the SURMOUNT-5 head-to-head actually proved. Until May 2025, every "tirzepatide vs semaglutide" comparison was cross-trial, meaning the two compounds had never been tested in the same study population. SURMOUNT-5 changed that. Same protocol, same duration, same titration rules, 751 adults randomized 1:1. Tirzepatide at max tolerated dose produced 20.2% mean weight loss vs. 13.7% for semaglutide at max tolerated dose over 72 weeks. That is a 6.5 percentage-point absolute gap, or roughly 47% more relative weight reduction on tirzepatide. Waist circumference also dropped more on tirzepatide (-18.4 cm vs -13.0 cm). This is the first time the GIP/GLP-1 advantage over GLP-1 alone has been proven in a direct comparison, and it is why I treat "tirzepatide beats semaglutide" as a settled question rather than an open debate.

What TRIUMPH-4 added. On December 11, 2025, Eli Lilly published topline Phase 3 TRIUMPH-4 results. In adults with obesity and knee osteoarthritis (mean baseline weight 248.5 lbs / 112.7 kg), retatrutide at 12 mg produced 28.7% mean weight loss at 68 weeks — an average of 71.2 lbs lost. At the 9 mg dose, participants lost 26.4% (64.2 lbs). Placebo was 2.1%. Notably, 58.6% of retatrutide-treated participants on the 12 mg dose achieved at least 25% weight loss at 68 weeks, a threshold that was vanishingly rare before this drug class existed. No head-to-head Phase 3 trial has been run between retatrutide and tirzepatide yet, so I'm careful not to claim retatrutide's Phase 3 numbers directly outperform tirzepatide's — they are cross-trial comparisons. But the efficacy signal is unambiguously larger.

The mechanism is the cleanest way to understand why the efficacy ladder looks the way it does. Think of each receptor as a separate metabolic lever.

The GLP-1 receptor (all three compounds activate this). GLP-1 is a gut hormone released when you eat. Activating its receptor does four useful things: it slows gastric emptying, so food stays in your stomach longer and you feel full; it suppresses appetite in the hypothalamus; it triggers glucose-dependent insulin release from the pancreas (meaning insulin goes up when blood sugar is high, not when it is already normal); and it reduces glucagon release when blood sugar is high. Semaglutide only pulls this lever.

The GIP receptor (tirzepatide and retatrutide activate this). GIP is a second incretin hormone. It amplifies insulin release and appears to modulate fat-tissue metabolism in ways researchers are still characterizing. Adding GIP activation on top of GLP-1 is the mechanism behind tirzepatide's efficacy advantage over semaglutide. The SURMOUNT-5 authors hypothesize that GIP receptor expression in subcortical brain regions that regulate food intake doesn't fully overlap with GLP-1 receptor expression, which may explain the additive effect.

The glucagon receptor (only retatrutide activates this). Here is where retatrutide separates from the other two. Glucagon is traditionally thought of as a blood-sugar-raising hormone — the opposite of insulin — which would seem to make it a bad target for obesity treatment. But when you combine glucagon receptor agonism with strong GLP-1 and GIP activity, something interesting happens: GLP-1 and GIP's insulin-stimulating effects offset glucagon's glucose-raising tendency, and what's left is glucagon's other effects — increased hepatic energy expenditure, upregulated fatty-acid oxidation, and thermogenesis. The liver starts burning lipids harder. Preclinical data suggested this would unlock liver-fat reduction that dual agonists could not match, and the Phase 2 retatrutide data confirmed large hepatic fat reductions.

The shorthand I use when explaining this: semaglutide reduces calories in. Tirzepatide reduces calories in and changes how those calories are metabolized. Retatrutide does both of those and increases calories out. Each added receptor opens a new lane of metabolic effect.

I pulled the primary publications for each pivotal trial and summarized the design and findings below. If you want to dig deeper, every trial links to its ClinicalTrials.gov record in the Sources section.

Semaglutide — STEP 1 (NEJM 2021). The trial that kicked off the modern obesity-medication era. 1,961 adults with obesity or overweight and at least one weight-related comorbidity but without diabetes. Randomized 2:1 to semaglutide 2.4 mg weekly vs. placebo, both with behavioral lifestyle intervention, for 68 weeks. Primary result: 14.9% mean body-weight reduction with semaglutide vs. 2.4% with placebo. Roughly 86% of semaglutide participants lost at least 5% of body weight, and about 32% lost at least 20%. Discontinuation due to adverse events was 7.0% in the semaglutide arm.

Tirzepatide — SURMOUNT-1 (NEJM 2022). 2,539 adults with obesity or overweight with comorbidity, without T2D. Randomized 1:1:1:1 to tirzepatide 5 mg, 10 mg, 15 mg, or placebo for 72 weeks. Primary result at 15 mg: 22.5% mean body-weight reduction vs. 2.4% placebo. Greater than 78% of participants on 15 mg achieved ≥15% weight loss, and 36% achieved ≥25%. This is still the single most impressive single-compound result in obesity-trial history up to the launch of TRIUMPH-4.

Head-to-head — SURMOUNT-5 (NEJM May 2025). This is the trial that settled the tirzepatide-vs-semaglutide debate. Phase 3b open-label design, 751 adults with obesity but without T2D, randomized 1:1 to max tolerated dose of tirzepatide (10 or 15 mg) or max tolerated dose of semaglutide (1.7 or 2.4 mg) for 72 weeks, both on top of behavioral support. Result: tirzepatide 20.2% mean weight loss vs. semaglutide 13.7%. 82% of tirzepatide participants hit ≥10% weight loss vs. 60.5% on semaglutide. 19.7% on tirzepatide hit ≥30% weight loss vs. 6.9% on semaglutide. Safety profiles were similar across both arms and consistent with prior trials for each compound. Serious adverse events were 4.8% on tirzepatide vs. 3.5% on semaglutide.

Retatrutide — Jastreboff Phase 2 (NEJM 2023). 338 adults with obesity without T2D. Randomized to retatrutide at 1 mg, 4 mg, 8 mg, or 12 mg weekly, or placebo, for 48 weeks. Primary result at 12 mg: 24.2% mean weight loss. About 83% of the 12 mg cohort achieved ≥15% weight loss. This is the data that justified proceeding to Phase 3.

Retatrutide — TRIUMPH-4 Phase 3 (Eli Lilly topline Dec 2025). 445 adults with obesity or overweight plus knee osteoarthritis, without T2D. Randomized 1:1:1 to retatrutide 9 mg, retatrutide 12 mg, or placebo for 68 weeks. Primary weight-loss endpoint: 28.7% mean reduction at 12 mg (avg 71.2 lbs lost) and 26.4% at 9 mg, vs. 2.1% placebo. Co-primary pain endpoint: WOMAC pain score reduced ~75.8% on 12 mg. Cardiovascular risk markers (non-HDL cholesterol, triglycerides, hsCRP, systolic blood pressure -14.0 mmHg at the highest dose) all improved significantly. Seven additional TRIUMPH Phase 3 readouts in obesity, type 2 diabetes, OSA, NASH, cardiovascular outcomes, and chronic low back pain are expected during 2026. Lilly has not yet submitted an NDA; based on readout pacing, I would project an NDA filing in late 2026 and a possible approval window in 2027 if results hold.

What's missing from this picture. There is no head-to-head Phase 3 trial of retatrutide vs. tirzepatide yet. All retatrutide-to-tirzepatide comparisons are cross-trial, meaning they are suggestive but not definitive. That caveat matters when people ask me "is retatrutide actually better than tirzepatide?" The honest answer is: the single-arm Phase 3 efficacy numbers are larger, but we do not have the direct comparison yet. Expect that trial to happen once retatrutide is approved.

All three compounds produce the same underlying GI side-effect pattern — nausea, diarrhea, vomiting, constipation — because they all slow gastric emptying and activate brainstem pathways that regulate nausea. What varies is the incidence, the severity curve, and (in retatrutide's case) the appearance of a new signal.

I want to flag the bottom two rows because they matter for the decision.

The dysesthesia signal. Dysesthesia — an unpleasant sensation on the skin, often described as crawling, tingling, or burning without obvious cause — showed up in about 1 in 5 participants on the retatrutide 12 mg arm in TRIUMPH-4. It was not reported in the Phase 2 trial. Lilly described it as generally mild and not typically a cause for discontinuation, but it is a new signal in this class. If you're tracking this drug's progression to approval, dysesthesia incidence in the remaining TRIUMPH readouts is one of the things I'll be watching for.

The retatrutide discontinuation rate. 18.2% of TRIUMPH-4 participants on the 12 mg retatrutide dose discontinued due to adverse events, compared to 4% on placebo. Lilly noted a portion of those were for "perceived excessive weight loss" rather than tolerability — patients with lower baseline BMIs were losing weight faster than they wanted. Restricting the analysis to participants with baseline BMI ≥35 cut the 12 mg discontinuation rate to 12.1%. The absolute 18.2% figure is higher than anything seen on tirzepatide, and prescribers (and researchers) should plan for more aggressive titration pausing.

Class-wide warnings that apply to all three. Acute pancreatitis, gallbladder events, thyroid C-cell concerns (a rat-derived signal that has never been confirmed in humans), and diabetic retinopathy progression in patients with existing retinopathy. These are boxed warnings or precautions across the approved GLP-1 class and should be assumed for retatrutide pending full FDA labeling. Contraindication for anyone with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.

For the full class-by-class side-effect review with monitoring guidance, see Peptide Side Effects: What Clinical Trials Actually Show. That guide covers the longitudinal data and what to actually do about GI symptoms during titration.

A note on why titration is slow. The GI side effects are dose-dependent. If you skip titration steps, you will likely push yourself through the threshold for significant nausea and vomiting, which is both miserable and a common cause of protocol discontinuation. In the trials, the titration schedule is not a suggestion — it's the protocol. Community protocols in the research market sometimes advocate for slower titration when tolerability is poor, and that is reasonable in my read of the data, but faster titration is a bad idea in every direction.

Missed doses. For semaglutide and tirzepatide, the FDA labels allow catch-up dosing within a specific window (check the prescribing info for specifics since this has changed across label updates). If you miss a dose by more than the allowed window, the next dose is simply the next scheduled dose. Do not "double up" to compensate. For retatrutide, there is no FDA label yet, but the Phase 3 trial protocols follow similar missed-dose logic.

Stopping and rebound. All three compounds produce weight rebound after discontinuation. STEP 4 showed semaglutide cessation led to most of the weight being regained over the following 52 weeks. SURMOUNT-4 showed similar patterns with tirzepatide cessation. Retatrutide data on this point is still being collected through the TRIUMPH maintenance arms. Sustained weight management on these compounds appears to be chronic therapy, not a discrete course.

For the full titration schedule, missed-dose logic, and clinical-trial-derived protocol for each compound, use the individual protocol pages:

• Semaglutide Dosing Protocol
• Tirzepatide Dosing Protocol
• Retatrutide Dosing Protocol

Standard reconstitution steps — all three compounds

1. Gather a sterile U-100 insulin syringe, bacteriostatic water, alcohol swab, and peptide vial.
2. Wipe the vial septum with alcohol and let it air-dry fully.
3. Draw the exact BAC water volume from the table above for your vial size.
4. Inject the BAC water slowly down the inside wall of the vial — not directly onto the lyophilized powder.
5. Let the vial rest undisturbed for 1–2 minutes.
6. Gently swirl or roll the vial between your palms until the solution is clear. Do not shake.
7. Label the vial with the compound, reconstitution date, concentration, and expiration window.

Syringe unit shorthand: 1 mL = 100 U on a U-100 insulin syringe. That conversion applies to every number in the tables above.

Storage after reconstitution: All three are stable in the refrigerator at 2–8 °C for approximately 28 days after reconstitution. Keep them in the original vial, protected from light. Do not freeze.

Use the free peptide reconstitution calculator · Shop injection supplies · Read the full reconstitution guide

The three compounds live in different parts of the regulatory landscape, which means the realistic paths to getting them are different. Here is how I break it down.

Semaglutide

• Pharmacy (primary path). FDA-approved as Wegovy (chronic weight management) and Ozempic (T2D). Telehealth prescribing is widely available. Insurance coverage for weight loss remains inconsistent — most commercial plans cover Ozempic for diabetes but not Wegovy for weight management. Cash prices without insurance typically run $900–$1,300 per month. Manufacturer savings programs from Novo Nordisk can reduce out-of-pocket costs for eligible patients.
• Compounding pharmacies. As of April 2026, FDA regulations around compounded GLP-1s have tightened significantly. Access through compounded semaglutide has narrowed compared to 2023–2024. See my PepPal news coverage of the FDA February 2026 ruling for context on what changed.
• Research market. Semaglutide is widely available from Finnrick-tested suppliers. Pricing is dramatically lower than pharmacy, but you take on the burden of sourcing verification, COA review, and self-administration logistics.

Tirzepatide

• Pharmacy (primary path). FDA-approved as Zepbound (chronic weight management) and Mounjaro (T2D). Same telehealth prescribing landscape as semaglutide. Cash prices similar to or slightly above semaglutide. Eli Lilly Direct launched a cash-pay vial program in 2024 that reduced out-of-pocket cost for self-pay patients.
• Compounding pharmacies. Same FDA crackdown applies. Access is narrowing.
• Research market. Widely available. Pricing in the Orbitrex supplier review I pulled runs $49.99–$59.99 for a 10 mg vial, $79.99–$89.99 for 15 mg, and $119.99–$129.99 for 30 mg at time of writing. Peptide Partners carries tirzepatide across similar size tiers but at different margin points.

Retatrutide

• Pharmacy. Not available. Retatrutide is investigational. There is no prescribed pharmacy access as of April 2026. This is the first thing to understand about it.
• Clinical trial enrollment. The TRIUMPH program is ongoing. Search "retatrutide" or trial ID NCT05931367 (TRIUMPH-4) and related NCT numbers on ClinicalTrials.gov to find active sites. Inclusion/exclusion criteria, geography, and recruitment status vary.
• Research market. Retatrutide is available from the PepPal-vetted suppliers. Orbitrex has an A Finnrick rating on retatrutide. Peptide Partners has an A Finnrick rating on retatrutide specifically in the current supplier review I maintain. For the full access-path breakdown including clinical trial options and supplier quality signals, see How Do You Get Retatrutide.

Research-market quality imperative

If you are sourcing any of these three through the research market, the quality-verification step is not optional. The GLP-1 category is the most counterfeited peptide class on the internet because demand is high and legitimate manufacturing is expensive. Do not buy from suppliers without visible third-party testing. I maintain the PepPal Supplier Directory with Finnrick Analytics quality ratings, and the How to Read a Peptide COA guide walks through what to look for in a Certificate of Analysis.

Cost caveats I would not skip.

• Pharmacy prices are moving targets. Both Novo and Lilly have adjusted direct-cash-pay programs multiple times in the last 18 months. The numbers above reflect April 2026 snapshots.
• Research-market prices look dramatically cheaper than pharmacy. They are. That price gap is not free — it reflects that you are absorbing quality-verification and administration risk that the pharmacy otherwise handles.
• Peptide Partners and Orbitrex both honor the PEPPAL discount code at checkout when eligible. Availability rules vary by supplier.
• If you are eligible for insurance coverage of Wegovy or Zepbound, that will almost always be the cheapest and lowest-risk access path. The research market is not meant to compete with covered insurance access.

Risk-adjusted take. For approved compounds (semaglutide and tirzepatide) with insurance coverage, pharmacy access is the dominant strategy — you get regulated supply, clinical oversight, and lower cost after insurance. Without coverage, the decision tilts toward manufacturer cash programs or the research market based on individual risk tolerance and ability to verify quality. For retatrutide, there is no pharmacy path today, so the realistic choice is clinical trial enrollment (highest-quality access but geographically limited) or research-market sourcing through Finnrick-verified suppliers.

After reviewing the data I laid out in the sections above, here is how I think about the decision. This is not a recommendation to use any of these compounds — it is a framework for understanding the tradeoffs.

Choose semaglutide if:

• You have insurance coverage of Wegovy and want the lowest-risk, lowest-cost approved access path.
• You want the compound with the longest real-world safety record in this class (approved since 2017 as Ozempic, 2021 for weight management as Wegovy).
• You have a history of poor GI tolerability and want to start with the least-aggressive compound in the class.
• You are new to GLP-1 class medications and want the most-documented titration and monitoring playbook.

Choose tirzepatide if:

• You want the best efficacy among FDA-approved options. SURMOUNT-5 settled this.
• You have previously tried semaglutide and plateaued without hitting your weight-loss target.
• You have insurance coverage of Zepbound or qualify for the Lilly Direct cash program.
• You are comfortable with a somewhat longer titration (20 weeks to 15 mg) in exchange for better efficacy.

Consider retatrutide if:

• You have already tried tirzepatide at max tolerated dose and plateaued.
• You have high baseline BMI where 28.7% weight loss represents a clinically meaningful target.
• You are willing to accept (a) investigational status, (b) a 12–18% discontinuation rate at the highest doses, and (c) the new dysesthesia signal at ~20% incidence.
• You have access either to a clinical trial site or to Finnrick-verified research-market sourcing.

When I would wait. If you are currently tolerating tirzepatide well and hitting your weight-loss goals, I would not jump to retatrutide solely because the Phase 3 efficacy numbers are bigger. The drug has one Phase 3 readout. Seven more are expected in 2026. The dysesthesia signal has not been fully characterized yet. The discontinuation rate is notably higher. For a researcher tracking this drug, waiting for the remaining TRIUMPH readouts and the FDA review cycle is a defensible position. For someone who has maxed out on tirzepatide and has an ongoing unmet need, the calculus looks different.

What I cannot tell you. Whether any of these compounds is right for you specifically. That requires a clinician who can review your medical history, current medications, lab work, and personal goals. Nothing on this page is medical advice, and the comparison framework above is not a substitute for a prescriber's judgment.

For the full compound-specific protocols — titration schedules, reconstitution math, and clinical evidence — use the protocol pages on PeptideDosingProtocols.com:

• Semaglutide Dosing Protocol
• Tirzepatide Dosing Protocol
• Retatrutide Dosing Protocol

Every number on this page is anchored to one of the sources below. Source tiers follow the hierarchy I use across PepPal and PeptideDosingProtocols.com — see my full methodology for how I grade evidence.

Tier 1 — Peer-reviewed clinical trial publications

1. Aronne LJ, Horn DB, le Roux CW, et al. "Tirzepatide as Compared with Semaglutide for the Treatment of Obesity." New England Journal of Medicine. 2025;393(1):26-36. DOI: 10.1056/NEJMoa2416394. https://www.nejm.org/doi/abs/10.1056/NEJMoa2416394 (SURMOUNT-5 head-to-head)
2. Wilding JPH, Batterham RL, Calanna S, et al. "Once-Weekly Semaglutide in Adults with Overweight or Obesity." New England Journal of Medicine. 2021;384(11):989-1002. DOI: 10.1056/NEJMoa2032183. (STEP 1)
3. Jastreboff AM, Aronne LJ, Ahmad NN, et al. "Tirzepatide Once Weekly for the Treatment of Obesity." New England Journal of Medicine. 2022;387(3):205-216. DOI: 10.1056/NEJMoa2206038. (SURMOUNT-1)
4. Jastreboff AM, Kaplan LM, Frías JP, et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial." New England Journal of Medicine. 2023;389(6):514-526. DOI: 10.1056/NEJMoa2301972. (Retatrutide Phase 2)
5. Kaplan LM, Aronne LJ, le Roux CW, et al. "Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials." 2025. PubMed PMID: 41090431. https://pubmed.ncbi.nlm.nih.gov/41090431/

Tier 2 — Systematic reviews and meta-analyses

6. Moiz A, et al. Systematic review of GLP-1 receptor agonists, dual, and triple co-agonists for weight loss in overweight or obese adults without diabetes. 26 RCTs, 15,491 participants. Indexed via TheNNT.com review, 2025.

Tier 3 — Manufacturer regulatory and trial communications

7. Eli Lilly and Company. "Lilly's triple agonist, retatrutide, delivered weight loss of up to an average of 71.2 lbs along with substantial relief from osteoarthritis pain in first successful Phase 3 trial." December 11, 2025. https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-delivered-weight-loss-average
8. ClinicalTrials.gov. "A Study of Retatrutide (LY3437943) Once Weekly in Participants Who Have Obesity or Overweight (TRIUMPH-4)." NCT05931367. https://clinicaltrials.gov/study/NCT05931367
9. ClinicalTrials.gov. "Tirzepatide Versus Semaglutide Once Weekly as Adjunct to a Reduced-Calorie Diet and Increased Physical Activity in Adult Participants With Obesity (SURMOUNT-5)." NCT05822830. https://clinicaltrials.gov/study/NCT05822830

Tier 3 — Peer secondary coverage (used for context, not primary data)

10. American College of Cardiology. "SURMOUNT-5: Greater Loss of Weight, Waist Circumference With Tirzepatide Than Semaglutide." July 2025. https://www.acc.org/Latest-in-Cardiology/Journal-Scans/2025/07/10/09/09/SURMOUNT-5
11. Pharmaceutical Executive. "Lilly's Retatrutide Displays Positive Topline Results in Successful Phase III Trial." December 2025. https://www.pharmexec.com/view/lilly-retatrutide-positive-topline-results-successful-phase-iii-trial

Related PepPal and PDP references (used for cross-linking, not primary data)

12. Best Peptides for Fat Loss (2026)
13. Peptide Side Effects: What Clinical Trials Actually Show (2026)
14. How Do You Get Retatrutide (2026)
15. Semaglutide Dosing Protocol
16. Tirzepatide Dosing Protocol
17. Retatrutide Dosing Protocol

Found an error? Email me at garret@peppal.app. Accuracy is the foundation of everything on this site and I take corrections seriously.

If you want the full compound-level dosing protocol

• Semaglutide Dosing Protocol — Full titration schedule, reconstitution math, and clinical-trial references.
• Tirzepatide Dosing Protocol — Full titration schedule, reconstitution math, and clinical-trial references.
• Retatrutide Dosing Protocol — Phase 3 titration, reconstitution math, and TRIUMPH program references.

If you are still comparing across the broader fat-loss peptide landscape

• Best Peptides for Fat Loss (2026) — The broader selection guide including CagriSema, AOD-9604, and MOTS-c.
• Peptide Stacking 101 — Why CagriSema-style amylin + GLP-1 stacks work and why GLP-1 + GLP-1 stacks do not.

If you are evaluating access paths

• How Do You Get Retatrutide (2026) — Full retatrutide access breakdown including ClinicalTrials.gov enrollment guidance.
• Best Grey-Market Peptide Suppliers (2026) — Finnrick-ranked supplier comparison.
• How to Read a Peptide COA — How to verify supplier quality claims before purchasing.

If you are ready to do the reconstitution math

• Free Peptide Reconstitution Calculator — I built this to handle vial-to-syringe math for any peptide, any vial size, any BAC water volume.
• How to Reconstitute Peptides — Step-by-step walkthrough with storage guidance.
• Injection Supplies Checklist — Syringes, BAC water, alcohol wipes, sharps disposal.

Safety context

• Peptide Side Effects: What Clinical Trials Actually Show (2026) — Class-by-class safety review.

Disclaimer: This article is for educational and informational purposes only. It is not medical advice. Semaglutide and tirzepatide are FDA-approved for specific indications. Retatrutide is investigational and not FDA-approved. Regulatory status and product availability vary by jurisdiction. Consult a qualified healthcare provider before considering any compound.

Affiliate disclosure: PepPal may earn a referral commission from suppliers linked on this page. Affiliate status does not affect quality ratings or rankings — suppliers are ranked by Finnrick Analytics data, not by commission rates. See the full affiliate policy on the About page.

Corrections: Email garret@peppal.app if you spot an error in any dosing table, reconstitution calculation, or clinical citation.