Independent · source-cited · no sponsored rankings
Which peptide actually works for weight loss?
We ranked every compound with published human data — one estimand, one time point, so the numbers sit next to each other honestly. Where human data does not exist, the page says so.
- 47
- guides and references
- 151
- linked primary sources
- 4
- checks before a recommendation
Weight-loss ranking 2026
mean weight change- 1RetatrutidePhase 3 · not approved−25.0%
- 2TirzepatideApproved · SURMOUNT-1−20.9%
- 3Semaglutide 2.4 mgApproved · STEP-1−14.9%
Dose calculator
drag the sliders2,500 mcg/ml · 0.10 ml 10 units
Start here
The two pages most readers open first.
Peptide Dosage Calculator
Enter the vial size, the water you added and your target dose. Get the concentration, the volume to draw, and the exact mark on a U-100 syringe — with a diagram that fills to match.
Open the calculator →Most requestedRetatrutide
The triple agonist with the largest weight reductions yet reported — and still no prescription pathway. Phase 3 data, titration, cost per month, and how to vet a source.
Read the guide →NewPeptide Research Database
Every source cited on this site in one filterable database — human trials, animal studies, in-vitro work and regulatory documents, each labeled by evidence class.
Browse the research →Weight and metabolic
Ranked by published trial results, using one estimand throughout so the comparisons hold.
GLP-1 Comparison Chart
Every agonist on one consistent analysis, with both estimand conventions shown.
Best Peptides for Weight Loss
Retatrutide, tirzepatide, CagriSema, semaglutide and survodutide, like-for-like.
Retatrutide Results
Every reported figure by dose and source tier, with the subgroup caveats attached.
Tirzepatide
The strongest results of any weight-loss drug a doctor can actually prescribe.
Semaglutide
Smaller numbers, and the only compound here proven to cut cardiovascular events.
Semaglutide vs Tirzepatide
The one pairing with a real head-to-head trial — no cross-trial guesswork needed.
CagriSema
Amylin instead of a second incretin — and the head-to-head trial it lost.
Survodutide
A dual agonist that lost to semaglutide on weight, and wins on the liver.
Best Peptides for Fat Loss
The same class judged on body composition — DEXA and imaging data, not the scale.
Retatrutide Dosage
Trial titration schedules, and what the 6 mg step is actually for.
Retatrutide Side Effects
Phase 3 rates by dose, the dysesthesia signal, and the titration fix.
Retatrutide Cost & Access
Trial enrollment, approval timeline, real monthly cost by dose.
5-Amino-1MQ
Not a peptide, and never tested in a human. Where the mouse data stops.
Repair and recovery
Deep animal literature, thin human evidence. Both stated plainly on every page.
BPC-157
Side effects, the gut and tendon evidence, and its 2026 compounding status.
TB-500
Why evidence about thymosin beta-4 is not evidence about the fragment sold.
BPC-157 + TB-500 Blend
The blend-vial math that halves the dose when people get it wrong.
KPV
The α-MSH tripeptide studied for gut and skin inflammation.
GHK-Cu
Strong lab story, one small negative human trial, nothing for injection.
GLOW Stack
Three peptides in one vial — and no study of the combination anywhere.
Growth hormone and mitochondrial
Where the marketing and the trial results diverge most sharply.
Tesamorelin
The only approved GHRH analog — Phase 3 data, liver fat, and the fine print.
Sermorelin
A former FDA drug sold for anti-aging. Where the evidence actually stops.
MK-677 (Ibutamoren)
A real trial record: two years of body-composition data, and a trial stopped early.
CJC-1295
Two forms sold under one name — one lasts days, the other half an hour.
CJC-1295 & Ipamorelin
DAC versus no-DAC, blend math, dose timing and side effects.
Best Peptides for Muscle Growth
What growth hormone research actually found about strength.
SS-31 (Elamipretide)
FDA approved for one rare disease — and it failed Phase 3 elsewhere.
MOTS-c
The mitochondrially encoded peptide, and the limits of its evidence.
Melanocortin and other
Including the two compounds on this site with the most documented harm.
Buying and safety
The part that decides whether what you have is what the label says.
Where to Buy Peptides
Four checks that separate a real supplier from a repackager.
Where to Buy Retatrutide
Four suppliers compared on price per mg and published COAs, with dated prices.
Are Peptides Safe?
Evidence tiers, side effects by class, and contamination risk.
Are Peptides Legal?
Four different legal positions, and why "research use only" is not a quality claim.
How to Reconstitute Peptides
The step where vials get ruined invisibly — technique, volumes and storage.
Bacteriostatic Water
What the approved label actually says about the 0.9% benzyl alcohol preservative.
How Much Do Peptides Cost?
Why price per mg is the only comparable number, and why cheap is a red flag.
How we review
Four checks before a compound gets a recommendation.
Published evidence
We read the primary literature on PubMed and ClinicalTrials.gov. If human data does not exist, we say so plainly instead of implying it does.
Published purity documentation
We check what a supplier actually publishes: a certificate tied to a specific lot, with named test methods. We read those documents — we do not run our own lab tests.
Dosing that matches trials
Reference ranges come from published protocols where they exist, converted into practical per-vial math with our calculator.
Supplier track record
Shipping reliability, batch consistency, responsiveness, and whether the company stands behind an order when something goes wrong.