24.2% Fat Loss in 48 Weeks: Vietnam's GLP-1 Reality in 2026

Want maximum weight loss → Retatrutide. The triple-agonist mechanism (GLP-1 + GIP + glucagon) makes retatrutide the most powerful weight loss peptide ever studied in clinical trials. The Phase 2 results showed 24.2% average body weight reduction over 48 weeks, which is substantially more than any dual-agonist or single-agonist compound.¹ The glucagon agonism directly increases metabolic rate and fat oxidation, particularly visceral fat. The tradeoff: retatrutide has no FDA approval yet, so you're limited to the research-grade path. That means verifying supplier COAs, reconstituting powder yourself, and accepting you're using a compound still in Phase 3 trials. If you're comfortable with that and want the highest possible efficacy, read the retatrutide Vietnam 2026 guide for pricing, sourcing, and legal status.

Want proven safety and the lowest cost → Semaglutide.² Semaglutide (Ozempic, Wegovy) has the longest track record of any GLP-1 peptide. The STEP clinical trials demonstrated 14.9% average weight loss over 68 weeks, and millions of people worldwide have used it since FDA approval in 2017 for diabetes and 2021 for obesity.² The safety profile is well understood, the side effect management is documented, and the research-grade cost is the lowest of the four options, typically ₫1.5 to 2.5M per month compared to ₫4 to 6M for retatrutide. In Vietnam, you have both the pharmacy route (Ozempic pens appear intermittently at pharmacies in HCMC and Hanoi) and the research-grade route. If you want to minimize cost and stick with the most proven compound, start with the semaglutide Vietnam 2026 guide.²

Want balance of efficacy and cost → Tirzepatide. Tirzepatide (Mounjaro, Zepbound) is the sweet spot for many people. It's a dual-agonist (GLP-1 + GIP) that demonstrated 22.5% average weight loss in the SURMOUNT trials, significantly more than semaglutide but not quite as high as retatrutide. [3] The GIP agonism appears to reduce nausea compared to pure GLP-1 drugs, which makes tirzepatide easier to tolerate for some users. In Vietnam, Mounjaro holds no marketing registration, so there is no registered hospital or pharmacy route for it and no hospital price to quote. [4] Research-grade tirzepatide is ₫1.5 to 3M per month and widely available from peptide suppliers. If you want FDA-approved efficacy through the route that actually exists in Vietnam, read the tirzepatide Vietnam 2026 guide.

Retatrutide

Retatrutide is a triple-agonist peptide that activates GLP-1, GIP, and glucagon receptors simultaneously, creating the most powerful metabolic shift of any weight loss compound ever studied. Phase 2 clinical trials showed 24.2% average body weight reduction over 48 weeks at the 12mg dose, and 83% of that group lost at least 15%.⁵ In Vietnam, retatrutide isn't available at any pharmacy or hospital, it remains an investigational Phase 3 compound globally. Your only path is research-grade sourcing from peptide suppliers who ship to Vietnam with cold-chain logistics. Pricing typically runs ₫4 to 6M per month at maintenance doses. The retatrutide Vietnam 2026 guide covers supplier verification, COA red flags, reconstitution protocols, and what expats need to know about legal status. Retatrutide is for people who want maximum efficacy, are comfortable with investigational compounds, and can handle the research-grade sourcing process.

Tirzepatide

Tirzepatide is a dual-agonist peptide that activates both GLP-1 and GIP receptors, delivering substantially more weight loss than single-agonist compounds while maintaining FDA approval and a strong safety profile. The SURMOUNT clinical trials demonstrated 22.5% average weight loss over 72 weeks at the 15mg dose, positioning tirzepatide between semaglutide and retatrutide in terms of efficacy.⁶ The GIP agonism appears to reduce GLP-1-driven nausea, making tirzepatide better tolerated than pure GLP-1 drugs for many users. In Vietnam, branded Mounjaro holds no marketing registration from the Drug Administration of Vietnam, so no hospital or licensed pharmacy has a registered supply of it to dispense and there is no hospital price to quote.⁴ Research-grade tirzepatide is widely available from peptide suppliers at ₫1.5 to 3M per month. The tirzepatide Vietnam 2026 guide breaks down the registration position, research-grade pricing, and the Mounjaro vs generic decision. Tirzepatide is the choice for people who want a compound with FDA-approved efficacy behind it, obtained through the research-grade route.⁷

Semaglutide

Semaglutide is a GLP-1 receptor agonist that sparked the global weight loss peptide revolution and remains the most widely used option worldwide. The STEP clinical trials demonstrated 14.9% average weight loss over 68 weeks at the 2.4mg dose, and the safety profile is the best understood of any GLP-1 drug thanks to years of real-world use.² Semaglutide is FDA-approved under two brand names: Ozempic (diabetes indication, 0.5 to 2mg doses) and Wegovy (obesity indication, up to 2.4mg).⁸ In Vietnam, Ozempic appears intermittently at pharmacies in District 1 and District 7 in HCMC, and occasionally in Hanoi expat areas, though availability is unpredictable. Research-grade semaglutide is the most affordable GLP-1 option at ₫1.5 to 2.5M per month and is widely available from peptide suppliers. The semaglutide Vietnam 2026 guide covers Ozempic vs research-grade sourcing, pharmacy hunting strategies, and pricing breakdowns. Semaglutide is the best choice for people new to GLP-1 peptides, those prioritizing cost, or anyone who wants the longest safety track record.

Cagrilintide

Cagrilintide is an amylin analogue that works through a completely different mechanism than GLP-1 agonists, making it a strong candidate for stacking rather than standalone use. Amylin is a hormone co-secreted with insulin that slows gastric emptying and suppresses appetite via different brain pathways than GLP-1. Phase 2 trials of cagrilintide alone showed approximately 10% weight loss, but the real promise is in combination therapy, Novo Nordisk is currently testing cagrilintide + semaglutide combinations in Phase 3 trials with early data suggesting additive effects beyond either drug alone.⁹ In Vietnam, cagrilintide is not available at any pharmacy or hospital and remains investigational globally. Research-grade cagrilintide is available from select peptide suppliers at ₫3 to 5M per month, though fewer suppliers stock it compared to the GLP-1 options. Most Vietnam-based users who experiment with cagrilintide do so by stacking it with semaglutide or tirzepatide to break through weight loss plateaus or enhance satiety. Cagrilintide is for advanced users who have already run a GLP-1 cycle and want to experiment with combination therapy.

What is the best peptide for weight loss or fat loss? Ranked by the mean body-weight reduction reported in their published obesity trials, retatrutide sits at the top: its Phase 2 trial in adults with obesity recorded 24.2% average reduction over 48 weeks at the 12mg dose (New England Journal of Medicine, 2023).⁵ Tirzepatide reached over 20% at the top 15mg dose over 72 weeks in the SURMOUNT-1 trial (NEJM, 2022), and semaglutide 14.9% over 68 weeks in STEP 1 (NEJM, 2021).³ So by trial effect size retatrutide is the strongest of the four, but it is still an investigational Phase 3 compound with no FDA approval, whereas tirzepatide and semaglutide are approved.¹³ This is education about what the trials measured, not a recommendation to take anything; the dose that fits a given person belongs with a licensed prescriber.

What is the best peptide for fat burning? Retatrutide is the only one of these four that adds glucagon-receptor agonism on top of GLP-1 and GIP, and glucagon agonism is associated with raised energy expenditure and fat oxidation; in its Phase 2 trial (NEJM, 2023) this contributed to a 24.2% average body-weight reduction over 48 weeks at the¹ 12mg dose. It is worth being precise about what "fat burning" means in this data: the weight and fat-mass loss in these trials in adults with obesity is driven mainly by reduced appetite and calorie intake, not by a targeted fat-burner effect, so results reflect an overall energy deficit rather than spot fat loss.

Best peptides for fat loss and weight loss in 2025 and 2026? The compounds with the strongest published fat-loss data heading into 2026 are the three incretin agonists on this page, retatrutide, tirzepatide, and semaglutide, plus the amylin analogue cagrilintide, which is studied mostly in combination with semaglutide rather than alone. Their standing has not changed between 2025 and 2026: retatrutide remains Phase 3 and unapproved, tirzepatide and semaglutide stay FDA-approved, and cagrilintide stays investigational.¹⁴ Retatrutide's 24.2% (NEJM, 2023) is still the largest average reduction reported in a published obesity trial among these compounds as of early 2026.⁵