#1
Semaglutide
FDA-approved GLP-1 receptor agonist with the largest clinical evidence base for weight and glycemic outcomes.
~7 daysSubcutaneous (weekly)
Best Peptides · fat loss
Best Peptides for Fat Loss in 2026
The fat-loss peptide conversation in 2026 is dominated by GLP-1 agonists, but the tracking layer is still where most users go wrong. The numbers that matter are not your scale weight — they are your ApoB, fasting insulin, HOMA-IR, and lean mass percentage over time. The peptides below cover the three mechanisms that show up in published trials: GLP-1 receptor agonism (semaglutide, tirzepatide, retatrutide), mitochondrial signaling (MOTS-c), and lipolytic fragmentation (AOD-9604). Each works differently, each has a different biomarker fingerprint, and each requires a different cadence of follow-up labs. This page links every option to its dose calculator, its biomarker tracking dashboard, and the comparison content that helps you discuss the choice with your provider — never as a recommendation, always as a structured framework for the actual conversation.
Editorial angle: Most fat-loss peptide guides are scale-weight focused; this one centers metabolic biomarkers because that is what determines whether the loss is sustainable.
5 peptides commonly tracked for fat loss
#2
Tirzepatide
FDA-approved dual GIP/GLP-1 receptor agonist with superior weight loss efficacy vs semaglutide in head-to-head data.
~5 daysSubcutaneous (weekly)
#3
Retatrutide
Investigational triple agonist (GLP-1 / GIP / glucagon) with the largest weight-loss effect of any compound yet reported in its class.
~6 daysSubcutaneous (weekly)
#4
MOTS-c
Mitochondrially-encoded peptide studied for metabolic and exercise-capacity effects.
Short; exact figures limitedSubcutaneous
#5
Aod-9604
Educational profile + dose calculator on MyProtocolStack.
What to Track on a Fat-Loss Protocol
Logging the protocol without the right biomarkers is half the picture. The labs below are the ones MyProtocolStack tracks alongside any fat loss protocol — establish a baseline, re-test on a consistent cadence, and compare your trend against the only reference that matters: yourself last quarter.
ApoBHbA1cFasting insulinHOMA-IRTriglyceridesBody fat %
Track these biomarkers free →Frequently Asked Questions
Which peptide drives the most fat loss?
In Phase 2 head-to-head data, retatrutide produced ~24% mean weight reduction at 48 weeks, tirzepatide ~22.5% in SURMOUNT-1, and semaglutide ~15% in STEP. Retatrutide is the largest-effect option among published trials, but it is not FDA-approved and access is research-only. Tirzepatide is FDA-approved as Mounjaro/Zepbound. The right choice is a clinical conversation, not a benchmark race.
How do I track whether the fat loss is sustainable?
Sustainable fat loss preserves lean mass and improves metabolic biomarkers (ApoB, fasting insulin, triglycerides) — it does not just move the scale. MyProtocolStack pairs your dose log with the biomarker dashboard so you see all three together over time.
Will I lose muscle on a GLP-1?
Published data suggests 25-40% of total weight lost on a GLP-1 is lean mass without structured resistance training and adequate protein. Tracking lean mass via DEXA every 3-4 months (or via the Vitals tab in MyProtocolStack) catches this early enough to adjust.
More peptide collections
For informational and educational purposes only. The peptides discussed on this page are not medical recommendations. MyProtocolStack is a tracking and education platform — it does not diagnose, prescribe, or provide clinical decision support. Always consult a licensed healthcare provider before starting, adjusting, or stopping any peptide protocol. Many peptides discussed here are not FDA-approved for the indications described and require a licensed prescription via a compounding pharmacy.