Peptide Fox
Download on the App StorePeptideFox for iPhoneFree on the App Store
AboutiOS AppArticlesPeptide LibraryCalculatorSupportPrivacy

© 2026 PeptideFox. For research and educational purposes only.

    Semaglutide vs Tirzepatide vs Retatrutide

    Semaglutide, tirzepatide, and retatrutide work through different receptor combinations which affect fat loss, muscle preservation, and metabolic breadth. This tool compares the compounds through clinical trial data — select a compound below.

    Download PeptideFox on the App StoreDownload PeptideFox on the App Store

    Semaglutide

    Ozempic, Wegovy

    beginner

    The gentle starter

    Pure GLP-1 agonist — reduces appetite and slows digestion. Strongest cardiovascular outcome data (SELECT trial), extensive trial and safety data, and only incretin with an oral option.

    Intensity
    2/5
    Tolerability
    4/5
    Support
    2/4
    Metabolic Scope

    GLP-1 only: satiety and insulin sensitivity

    Weight Loss Ratio
    60% fat40% lean

    STEP-1 DXA substudy, non-diabetic obesity, 68 wk

    Tirzepatide

    Mounjaro, Zepbound

    intermediate

    The fast track

    GIP-dominant dual agonist — directly engages fat cells via GIP receptors. 47% more weight loss than semaglutide head-to-head. Body-comp advantage narrows in T2D where GIP is impaired.

    Intensity
    4/5
    Tolerability
    3/5
    Support
    3/4
    Metabolic Scope

    GLP-1 + GIP: deeper metabolic rebalancing with improved nutrient partitioning

    Weight Loss Ratio
    75% fat25% lean

    SURMOUNT-1 DXA substudy, non-diabetic obesity, 72 wk

    Retatrutide

    Investigational (Phase 2)

    advanced

    The heavy hitter

    Triple-agonist with redesigned receptor profile — stronger GIP (2×), plus glucagon for direct liver fat mobilization. Currently in Phase II trials. Requires meticulous muscle protection.

    Intensity
    5/5
    Tolerability
    2/5
    Support
    4/4
    Metabolic Scope

    GLP-1 + GIP + Glucagon: whole-system metabolic rewiring with enhanced fat oxidation

    Weight Loss Ratio*
    63% fat37% lean

    *T2D population only, 48 wk (not directly comparable)

    GLP-1
    Satiety
    +
    GIP
    Insulin
    +
    Glucagon
    Energy
    Intensity
    2/5
    Tolerability
    4/5
    Support Needed
    2/4
    Metabolic
    1/5
    Data source:STEP-1●Non-diabetic obesity●68 weeks

    How It Works

    GLP-1
    1×

    Full-strength activation of the gut–brain satiety pathway — suppresses appetite, slows gastric emptying, and improves insulin signaling.

    Weight Loss Ratio
    60% fat loss40% lean loss
    −14.9%
    Avg. Weight Loss
    −27%
    Visceral Fat Reduction
    −30%+
    Liver Fat Reduction
    −13.5 cm
    Waist Circumference

    Smaller hunger signals, earlier fullness, flatter post-meal glucose spikes. Semaglutide's advantage is elsewhere: strongest cardiovascular outcome data (SELECT trial — 20% MACE reduction vs placebo) and the only incretin with an oral option. If you just 'let it run,' you'll lose lean mass at a rapid rate.

    What % of People Hit Each Milestone?

    Lost ≥5%
    86%
    Lost ≥10%
    69%
    Lost ≥15%
    50%
    Lost ≥20%
    33%

    Based on STEP-1 trial data (68 weeks, non-diabetic obesity)

    Expected Weight Loss by Dose

    DoseWeeksExpected LossNotes
    0.25 mg0–4~1%Early titration
    0.5 mg4–82–3%Appetite suppression begins
    1.0 mg8–124–6%Noticeable trajectory
    1.7 mg12–167–9%Most reach ≥5%
    2.4 mg16–6812–15%Full effect

    Complete Protocol Guide

    1

    Start

    Week 1-4
    Assess Tolerance
    0.25 mg weekly for 4 weeks
    What Happens
    Appetite suppression begins
    Early GI side effects
    1-2% weight loss
    Hunger stabilizes
    2

    Build

    Week 5-12+
    Progressive Escalation
    Increase every 4 weeks: 0.5 → 1.0 → 1.7 → 2.4 mg
    What Happens
    Fat loss begins
    3-5% total weight loss
    Improved glycemic markers
    Strength preserved with support
    3

    Maintain

    Month 3-6+
    Optimization Phase
    Lowest dose that controls appetite without hurting training
    What Happens
    Visceral fat ↓ 20-25%
    10-12% total weight loss
    REE down 10-15%
    Steady metabolism with training
    Maximum Dose
    2.4 mg weekly

    Do not exceed this dosage. Always follow your healthcare provider's guidance.

    Key Guidance
    Dose Considerations

    Only increase if appetite returns or fat loss stalls. Slow and steady wins.

    Advantages

    • Most forgiving - easiest to start and adjust.
    • Well-studied with good safety profile.

    Watch Out For

    • Effects of a 'blunt-instrument' that catabolizes muscle as the driving force is slowed gastric emptying.
    • Fatigue, lethargy, and reduced libido are common side effects.

    Semaglutide: Deep Dives

    Semaglutide Guide

    Dosing, side effects, and clinical trial data for Ozempic and Wegovy

    Support Stacks for GLP-1s

    How to preserve lean mass during GLP-1 therapy

    Clinical Monitoring Framework

    Lean Mass (DXA/BIA)
    >10% relative lean mass loss
    Frequency:Baseline + every 3-6 months
    Action:Reassess diet, slow titration, intensify resistance training
    Strength Metrics
    >10% strength drop without recovery
    Frequency:Monthly to quarterly
    Action:Hold dose, reduce training volume, review nutrition
    Protein Intake
    <1.2 g/kg trending
    Frequency:Weekly logs
    Action:Nutrition consult, meal plan revision, protein supplementation
    Resting Heart Rate
    +10 bpm above baseline
    Frequency:Weekly
    Action:Evaluate hydration, training stress, consider dose adjustment
    REE/Metabolic Rate
    >15% drop beyond adaptation
    Frequency:Every 3-6 months
    Action:Examine lean mass loss, adjust caloric intake

    Clinical Evidence

    Medical Disclaimer

    The content in this GLP-1 comparison guide is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before beginning any new protocol, supplement, or medication.

    GLP-1
    Satiety
    +
    GIP
    Insulin
    +
    Glucagon
    Energy
    Intensity
    4/5
    Tolerability
    3/5
    Support Needed
    3/4
    Metabolic
    3/5
    Data source:SURMOUNT-1●Non-diabetic obesity●72 weeks

    How It Works

    GLP-1
    0.2×

    Lower dose than semaglutide because GIP carries most of the weight — still provides appetite suppression and gastric slowing

    GIP
    1×

    Burns fat directly — GIP receptors sit on fat cells themselves, triggering heat generation through a pathway GLP-1 cannot access

    Weight Loss Ratio
    75% fat loss25% lean loss
    −21%
    Avg. Weight Loss
    −25%
    Visceral Fat Reduction
    −47%
    Liver Fat Reduction
    −19.9 cm
    Waist Circumference

    In non-diabetic populations, tirzepatide produces 47% more weight loss than semaglutide (SURMOUNT-5) and substantially better body composition (75:25 vs 60:40). In T2D, the ratio advantage disappears — head-to-head shows ~87:13 for both drugs. Still catabolizes muscle if you don't guard it.

    What % of People Hit Each Milestone?

    Lost ≥5%
    >95%
    Lost ≥10%
    91%
    Lost ≥15%
    83%
    Lost ≥20%
    57%
    Lost ≥25%
    36%

    Based on SURMOUNT-1 trial data (72 weeks, non-diabetic obesity)

    Expected Weight Loss by Dose

    DoseWeeksExpected LossNotes
    2.5 mg0–4~2%Starting dose
    5 mg4–84–6%Entry therapeutic
    7.5 mg8–128–10%Building
    10 mg12–1612–15%Strong effect
    15 mg16–7218–21%Maximum dose

    Complete Protocol Guide

    1

    Start

    Week 1-4
    Assess Tolerance
    2.5-5 mg weekly for 4 weeks
    What Happens
    Appetite ↓ sharply
    Glucose stabilizes
    2-4% weight loss
    GI symptoms if escalated too fast
    2

    Build

    Week 5-12+
    Progressive Escalation
    Increase every 4 weeks: 7.5 → 10 → 12.5 → 15 mg
    What Happens
    Fat loss 6-8%
    Energy steady via GIP
    Lean retention high
    Sleep/breathing improves
    3

    Maintain

    Month 3-6+
    Optimization Phase
    Lowest dose keeping hunger controlled and training normal
    What Happens
    10-15% total weight loss
    Visceral fat ↓ 25-35%
    Metabolic adaptation mild
    Performance sustained with support
    Maximum Dose
    15 mg weekly

    Do not exceed this dosage. Always follow your healthcare provider's guidance.

    Key Guidance
    Dose Considerations

    More powerful than sema - watch muscle loss if support isn't dialed in

    Advantages

    • Faster fat loss than semaglutide in head-to-head studies.
    • Strong glucose control for diabetics.

    Watch Out For

    • Higher chance of GI side effects.
    • Will catabolize muscle if anabolic support isn't dialed.

    Tirzepatide: Deep Dives

    Tirzepatide Guide

    Dosing, side effects, and clinical trial data for Mounjaro and Zepbound

    Support Stacks for GLP-1s

    How to preserve lean mass during GLP-1 therapy

    Clinical Monitoring Framework

    Lean Mass (DXA/BIA)
    >10% relative lean mass loss
    Frequency:Baseline + every 3-6 months
    Action:Hold dose escalation, boost protein to ≥1.8 g/kg, increase resistance training frequency
    Strength Metrics
    >10% strength drop
    Frequency:Monthly to quarterly
    Action:Freeze at current dose, deload training, review anabolic support
    Protein Intake
    <1.6 g/kg
    Frequency:Weekly logs
    Action:Immediate nutrition intervention, protein shakes between meals
    Resting Heart Rate
    +8 bpm above baseline
    Frequency:Weekly
    Action:Monitor for GIP-related effects, adjust training volume

    Clinical Evidence

    Medical Disclaimer

    The content in this GLP-1 comparison guide is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before beginning any new protocol, supplement, or medication.

    GLP-1
    Satiety
    +
    GIP
    Insulin
    +
    Glucagon
    Energy
    Intensity
    5/5
    Tolerability
    2/5
    Support Needed
    4/4
    Metabolic
    5/5
    Data source:Phase 2 (NEJM 2023)●Non-diabetic obesity (weight loss); T2D substudy (body comp, 36-wk DXA)●48 weeks

    How It Works

    GLP-1
    0.5×

    Mid-range dose — appetite suppression and gastric slowing, balanced against two stronger receptor channels

    GIP
    2×

    Double-strength fat cell activation — Lilly engineered this to overcome the blunted GIP response seen in type 2 diabetes

    Glucagon
    0.2×

    Unique to retatrutide — tells the liver to mobilize stored fat directly, increasing energy expenditure

    Weight Loss Ratio*
    63% fat loss37% lean loss
    −24.2%
    Avg. Weight Loss
    −45 to −50%
    Visceral Fat Reduction
    −86%
    Liver Fat Reduction
    −18 to −20 cm
    Waist Circumference

    Stronger GIP + glucagon means retatrutide hit ~17% weight loss in T2D at 36 weeks — vs tirzepatide's ~13% at 40 weeks. The glucagon channel works regardless of diabetic status. But glucagon is inherently catabolic and raises heart rate (+2–7 bpm). Non-negotiable anabolic support required.

    *Body composition data comes from a Phase 2 DXA substudy in a T2D population (48 weeks). Semaglutide and tirzepatide ratios are from non-diabetic populations over longer durations (68–72 weeks). Metabolic differences between T2D and non-diabetic subjects affect how fat and lean mass respond to treatment, so these ratios are not directly comparable across compounds. Non-diabetic retatrutide body composition data does not yet exist.

    What % of People Hit Each Milestone?

    Lost ≥5%
    100%
    Lost ≥10%
    93%
    Lost ≥15%
    83%
    Lost ≥20%
    63%
    Lost ≥25%
    ~40%
    Lost ≥30%
    ~25%

    Based on Phase 2 (NEJM 2023) trial data (48 weeks, non-diabetic obesity (weight loss); t2d substudy (body comp, 36-wk dxa))

    Expected Weight Loss by Dose

    DoseWeeksExpected LossNotes
    0.5–1 mg0–4~3%Activation phase
    2 mg4–85–7%Early response
    4 mg8–1210–12%Similar to full sema
    8 mg12–2418–20%Large effect
    12 mg24–4822–24%Maximum; no plateau

    Complete Protocol Guide

    1

    Start

    Week 1-4
    Assess Tolerance
    0.5-2 mg weekly, hold each step ≥4 weeks
    What Happens
    Appetite & thermogenesis begin
    3-5% weight loss
    HR ↑ 2-4 bpm
    Watch for early strength dip
    2

    Build

    Week 5-12+
    Progressive Escalation
    Advance only after plateau: 1 → 2 → 3 → 4 up to 12 mg
    What Happens
    Fat oxidation ↑, liver fat ↓
    8-10% weight loss
    Visceral fat drops rapidly
    Lean preserved ONLY with tight support
    3

    Maintain

    Month 3-6+
    Optimization Phase
    Lowest dose keeping appetite/weight trending
    What Happens
    Full thermogenic drive
    Visceral fat ↓ 40%
    18-24% total weight loss
    Lean risk highest - monitor closely
    Maximum Dose
    12 mg weekly

    Do not exceed this dosage. Always follow your healthcare provider's guidance.

    Key Guidance
    Dose Considerations

    Glucagon boosts energy expenditure but can catabolize muscle and increase need for carbohydrate intake if training too hard - slow titration essential.

    Advantages

    • Highest fat loss potential of any available option.
    • Impacts metabolism and drives fat oxidation with glucagon.

    Watch Out For

    • Side effects highly sensitive to dose escalation.
    • Elevated heart-rate during initial titration phases.

    Retatrutide: Deep Dives

    Retatrutide Guide

    Triple-agonist dosing and Phase 2 trial data

    Support Stacks for GLP-1s

    How to preserve lean mass during GLP-1 therapy

    Retatrutide + NAD+ Protocol

    Improved fat loss without the energy crash

    Retatrutide: Dual-Axis Protocol

    Protect lean mass while maximizing fat loss

    Clinical Monitoring Framework

    Lean Mass (DXA/BIA)
    >10% relative lean mass loss
    Frequency:Baseline + every 3 months
    Action:STOP escalation immediately, reduce to previous dose, verify anabolic support
    Strength Metrics
    >8% strength drop
    Frequency:Every 2 weeks
    Action:Freeze dose for 4+ weeks, review protein/training, consider dose reduction
    Protein Intake
    <1.6 g/kg
    Frequency:Daily tracking
    Action:Emergency intervention - protein shakes mandatory, pause escalation
    Resting Heart Rate
    +12 bpm above baseline
    Frequency:Daily (morning)
    Action:Glucagon effect assessment, reduce training stress, hydration check
    RMR/Metabolic Rate
    >10% drop (glucagon should offset)
    Frequency:Every 2-3 months
    Action:Investigate lean mass loss, caloric adequacy, thyroid panel
    Visual Assessment
    'Stringy' appearance emerging
    Frequency:Weekly photos
    Action:Immediate dose hold, anabolic support review, nutrition consult

    Clinical Evidence

    Medical Disclaimer

    The content in this GLP-1 comparison guide is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before beginning any new protocol, supplement, or medication.